-funroll-loops -funsafe-math-optimizations -funswitch-loops
-fipa-ra -fvariable-expansion-in-unroller -fvect-cost-model -fvpt
-fweb -fwhole-program -fwpa -fuse-linker-plugin -fzero-call-used-regs
---param @var{name}=@var{value}
-O -O0 -O1 -O2 -O3 -Os -Ofast -Og -Oz --optimize}
@item Program Instrumentation Options
--print-multiarch --print-prog-name=@var{program}
--print-search-dirs --print-sysroot --print-sysroot-headers-suffix
--save-temps
+--param @var{name}=@var{value}
}
@item Machine-Dependent Options
You can control this behavior for a specific function by using the function
attribute @code{zero_call_used_regs} (@pxref{Function Attributes}).
-
-@opindex param
-@item --param @var{name}=@var{value}
-@itemx --param=@var{name}=@var{value}
-In some places, GCC uses various constants to control the amount of
-optimization that is done. For example, GCC does not inline functions
-that contain more than a certain number of instructions. You can
-control some of these constants on the command line using the
-@option{--param} option.
-
-The names of specific parameters, and the meaning of the values, are
-tied to the internals of the compiler, and are subject to change
-without notice in future releases.
-
-In order to get the minimal, maximal and default values of a parameter,
-use the @option{--help=param -Q} options.
-
-In each case, the @var{value} is an integer. The following choices
-of @var{name} are recognized for all targets:
-
-@table @gcctabopt
-@item auto-profile-bbs
-If non-zero and used together with @option{-fauto-profile}, the auto-profile
-will be used to determine basic block profile. If zero, then only function
-level profile will be read.
-
-@item auto-profile-reorder-only
-Enable only function reordering with auto-profile.
-
-@item phiopt-factor-max-stmts-live
-When factoring statements out of if/then/else, this is the max # of statements
-after the defining statement to be allow to extend the lifetime of a name
-
-@item predictable-branch-outcome
-When branch is predicted to be taken with probability lower than this threshold
-(in percent), then it is considered well predictable.
-
-@item max-rtl-if-conversion-insns
-RTL if-conversion tries to remove conditional branches around a block and
-replace them with conditionally executed instructions. This parameter
-gives the maximum number of instructions in a block which should be
-considered for if-conversion. The compiler will
-also use other heuristics to decide whether if-conversion is likely to be
-profitable.
-
-@item file-cache-files
-Max number of files in the file cache.
-The file cache is used to print source lines in diagnostics and do some
-source checks like @option{-Wmisleading-indentation}.
-
-@item file-cache-lines
-Max number of lines to index into file cache. When 0 this is automatically sized.
-The file cache is used to print source lines in diagnostics and do some
-source checks like @option{-Wmisleading-indentation}.
-
-@item max-rtl-if-conversion-predictable-cost
-RTL if-conversion will try to remove conditional branches around a block
-and replace them with conditionally executed instructions. These parameters
-give the maximum permissible cost for the sequence that would be generated
-by if-conversion depending on whether the branch is statically determined
-to be predictable or not. The units for this parameter are the same as
-those for the GCC internal seq_cost metric. The compiler will try to
-provide a reasonable default for this parameter using the BRANCH_COST
-target macro.
-
-@item max-crossjump-edges
-The maximum number of incoming edges to consider for cross-jumping.
-The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in
-the number of edges incoming to each block. Increasing values mean
-more aggressive optimization, making the compilation time increase with
-probably small improvement in executable size.
-
-@item min-crossjump-insns
-The minimum number of instructions that must be matched at the end
-of two blocks before cross-jumping is performed on them. This
-value is ignored in the case where all instructions in the block being
-cross-jumped from are matched.
-
-@item max-grow-copy-bb-insns
-The maximum code size expansion factor when copying basic blocks
-instead of jumping. The expansion is relative to a jump instruction.
-
-@item max-goto-duplication-insns
-The maximum number of instructions to duplicate to a block that jumps
-to a computed goto. To avoid @math{O(N^2)} behavior in a number of
-passes, GCC factors computed gotos early in the compilation process,
-and unfactors them as late as possible. Only computed jumps at the
-end of a basic blocks with no more than max-goto-duplication-insns are
-unfactored.
-
-@item max-delay-slot-insn-search
-The maximum number of instructions to consider when looking for an
-instruction to fill a delay slot. If more than this arbitrary number of
-instructions are searched, the time savings from filling the delay slot
-are minimal, so stop searching. Increasing values mean more
-aggressive optimization, making the compilation time increase with probably
-small improvement in execution time.
-
-@item max-delay-slot-live-search
-When trying to fill delay slots, the maximum number of instructions to
-consider when searching for a block with valid live register
-information. Increasing this arbitrarily chosen value means more
-aggressive optimization, increasing the compilation time. This parameter
-should be removed when the delay slot code is rewritten to maintain the
-control-flow graph.
-
-@item max-devirt-targets
-This limits number of function a virtual call may be speculatively
-devirtualized to using static analysis (without profile feedback).
-
-@item max-gcse-memory
-The approximate maximum amount of memory in @code{kB} that can be allocated in
-order to perform the global common subexpression elimination
-optimization. If more memory than specified is required, the
-optimization is not done.
-
-@item max-gcse-insertion-ratio
-If the ratio of expression insertions to deletions is larger than this value
-for any expression, then RTL PRE inserts or removes the expression and thus
-leaves partially redundant computations in the instruction stream.
-
-@item max-pending-list-length
-The maximum number of pending dependencies scheduling allows
-before flushing the current state and starting over. Large functions
-with few branches or calls can create excessively large lists which
-needlessly consume memory and resources.
-
-@item max-modulo-backtrack-attempts
-The maximum number of backtrack attempts the scheduler should make
-when modulo scheduling a loop. Larger values can exponentially increase
-compilation time.
-
-@item max-inline-functions-called-once-loop-depth
-Maximal loop depth of a call considered by inline heuristics that tries to
-inline all functions called once.
-
-@item max-inline-functions-called-once-insns
-Maximal estimated size of functions produced while inlining functions called
-once.
-
-@item max-inline-insns-single
-Several parameters control the tree inliner used in GCC@. This number sets the
-maximum number of instructions (counted in GCC's internal representation) in a
-single function that the tree inliner considers for inlining. This only
-affects functions declared inline and methods implemented in a class
-declaration (C++).
-
-
-@item max-inline-insns-auto
-When you use @option{-finline-functions} (included in @option{-O3}),
-a lot of functions that would otherwise not be considered for inlining
-by the compiler are investigated. To those functions, a different
-(more restrictive) limit compared to functions declared inline can
-be applied (@option{--param max-inline-insns-auto}).
-
-@item max-inline-insns-small
-This is the bound applied to calls that are considered relevant with
-@option{-finline-small-functions}.
-
-@item max-inline-insns-size
-This is the bound applied to calls that are optimized for size. Small growth
-may be desirable to anticipate optimization opportunities exposed by inlining.
-
-@item uninlined-function-insns
-Number of instructions accounted by inliner for function overhead such as
-function prologue and epilogue.
-
-@item uninlined-function-time
-Extra time accounted by inliner for function overhead such as time needed to
-execute function prologue and epilogue.
-
-@item inline-heuristics-hint-percent
-The scale (in percents) applied to @option{inline-insns-single},
-@option{inline-insns-single-O2}, @option{inline-insns-auto}
-when inline heuristics hints that inlining is
-very profitable (will enable later optimizations).
-
-@item uninlined-thunk-insns
-@item uninlined-thunk-time
-Same as @option{--param uninlined-function-insns} and
-@option{--param uninlined-function-time} but applied to function thunks.
-
-@item inline-min-speedup
-When estimated performance improvement of caller + callee runtime exceeds this
-threshold (in percent), the function can be inlined regardless of the limit on
-@option{--param max-inline-insns-single} and @option{--param
-max-inline-insns-auto}.
-
-@item large-function-insns
-The limit specifying really large functions. For functions larger than this
-limit after inlining, inlining is constrained by
-@option{--param large-function-growth}. This parameter is useful primarily
-to avoid extreme compilation time caused by non-linear algorithms used by the
-back end.
-
-@item large-function-growth
-Specifies maximal growth of large functions caused by inlining in percents.
-For example, parameter value 100 limits large function growth to 2.0 times
-the original size.
-
-@item large-unit-insns
-The limit specifying large translation unit. Growth caused by inlining of
-units larger than this limit is limited by @option{--param inline-unit-growth}.
-For small units this might be too tight.
-For example, consider a unit consisting of function A
-that is inline and B that just calls A three times. If B is small relative to
-A, the growth of unit is 300\% and yet such inlining is very sane. For very
-large units consisting of small inlineable functions, however, the overall unit
-growth limit is needed to avoid exponential explosion of code size. Thus for
-smaller units, the size is increased to @option{--param large-unit-insns}
-before applying @option{--param inline-unit-growth}.
-
-@item lazy-modules
-Maximum number of concurrently open C++ module files when lazy loading.
-
-@item inline-unit-growth
-Specifies maximal overall growth of the compilation unit caused by inlining.
-For example, parameter value 20 limits unit growth to 1.2 times the original
-size. Cold functions (either marked cold via an attribute or by profile
-feedback) are not accounted into the unit size.
-
-@item ipa-cp-unit-growth
-Specifies maximal overall growth of the compilation unit caused by
-interprocedural constant propagation. For example, parameter value 10 limits
-unit growth to 1.1 times the original size.
-
-@item ipa-cp-large-unit-insns
-The size of translation unit that IPA-CP pass considers large.
-
-@item large-stack-frame
-The limit specifying large stack frames. While inlining the algorithm is trying
-to not grow past this limit too much.
-
-@item large-stack-frame-growth
-Specifies maximal growth of large stack frames caused by inlining in percents.
-For example, parameter value 1000 limits large stack frame growth to 11 times
-the original size.
-
-@item max-inline-insns-recursive
-@itemx max-inline-insns-recursive-auto
-Specifies the maximum number of instructions an out-of-line copy of a
-self-recursive inline
-function can grow into by performing recursive inlining.
-
-@option{--param max-inline-insns-recursive} applies to functions
-declared inline.
-For functions not declared inline, recursive inlining
-happens only when @option{-finline-functions} (included in @option{-O3}) is
-enabled; @option{--param max-inline-insns-recursive-auto} applies instead.
-
-@item max-inline-recursive-depth
-@itemx max-inline-recursive-depth-auto
-Specifies the maximum recursion depth used for recursive inlining.
-
-@option{--param max-inline-recursive-depth} applies to functions
-declared inline. For functions not declared inline, recursive inlining
-happens only when @option{-finline-functions} (included in @option{-O3}) is
-enabled; @option{--param max-inline-recursive-depth-auto} applies instead.
-
-@item min-inline-recursive-probability
-Recursive inlining is profitable only for function having deep recursion
-in average and can hurt for function having little recursion depth by
-increasing the prologue size or complexity of function body to other
-optimizers.
-
-When profile feedback is available (see @option{-fprofile-generate}) the actual
-recursion depth can be guessed from the probability that function recurses
-via a given call expression. This parameter limits inlining only to call
-expressions whose probability exceeds the given threshold (in percents).
-
-@item early-inlining-insns
-Specify growth that the early inliner can make. In effect it increases
-the amount of inlining for code having a large abstraction penalty.
-
-@item max-early-inliner-iterations
-Limit of iterations of the early inliner. This basically bounds
-the number of nested indirect calls the early inliner can resolve.
-Deeper chains are still handled by late inlining.
-
-@item comdat-sharing-probability
-Probability (in percent) that C++ inline function with comdat visibility
-are shared across multiple compilation units.
-
-@item modref-max-bases
-@item modref-max-refs
-@item modref-max-accesses
-Specifies the maximal number of base pointers, references and accesses stored
-for a single function by mod/ref analysis.
-
-@item modref-max-tests
-Specifies the maxmal number of tests alias oracle can perform to disambiguate
-memory locations using the mod/ref information. This parameter ought to be
-bigger than @option{--param modref-max-bases} and @option{--param
-modref-max-refs}.
-
-@item modref-max-depth
-Specifies the maximum depth of DFS walk used by modref escape analysis.
-Setting to 0 disables the analysis completely.
-
-@item modref-max-escape-points
-Specifies the maximum number of escape points tracked by modref per SSA-name.
-
-@item modref-max-adjustments
-Specifies the maximum number the access range is enlarged during modref dataflow
-analysis.
-
-@item profile-func-internal-id
-A parameter to control whether to use function internal id in profile
-database lookup. If the value is 0, the compiler uses an id that
-is based on function assembler name and filename, which makes old profile
-data more tolerant to source changes such as function reordering etc.
-
-@item min-vect-loop-bound
-The minimum number of iterations under which loops are not vectorized
-when @option{-ftree-vectorize} is used. The number of iterations after
-vectorization needs to be greater than the value specified by this option
-to allow vectorization.
-
-@item gcse-cost-distance-ratio
-Scaling factor in calculation of maximum distance an expression
-can be moved by GCSE optimizations. This is currently supported only in the
-code hoisting pass. The bigger the ratio, the more aggressive code hoisting
-is with simple expressions, i.e., the expressions that have cost
-less than @option{gcse-unrestricted-cost}. Specifying 0 disables
-hoisting of simple expressions.
-
-@item gcse-unrestricted-cost
-Cost, roughly measured as the cost of a single typical machine
-instruction, at which GCSE optimizations do not constrain
-the distance an expression can travel. This is currently
-supported only in the code hoisting pass. The lesser the cost,
-the more aggressive code hoisting is. Specifying 0
-allows all expressions to travel unrestricted distances.
-
-@item max-hoist-depth
-The depth of search in the dominator tree for expressions to hoist.
-This is used to avoid quadratic behavior in hoisting algorithm.
-The value of 0 does not limit on the search, but may slow down compilation
-of huge functions.
-
-@item max-tail-merge-comparisons
-The maximum amount of similar bbs to compare a bb with. This is used to
-avoid quadratic behavior in tree tail merging.
-
-@item max-tail-merge-iterations
-The maximum amount of iterations of the pass over the function. This is used to
-limit compilation time in tree tail merging.
-
-@item store-merging-allow-unaligned
-Allow the store merging pass to introduce unaligned stores if it is legal to
-do so.
-
-@item max-stores-to-merge
-The maximum number of stores to attempt to merge into wider stores in the store
-merging pass.
-
-@item max-store-chains-to-track
-The maximum number of store chains to track at the same time in the attempt
-to merge them into wider stores in the store merging pass.
-
-@item max-stores-to-track
-The maximum number of stores to track at the same time in the attemt to
-to merge them into wider stores in the store merging pass.
-
-@item max-unrolled-insns
-The maximum number of instructions that a loop may have to be unrolled.
-If a loop is unrolled, this parameter also determines how many times
-the loop code is unrolled.
-
-@item max-average-unrolled-insns
-The maximum number of instructions biased by probabilities of their execution
-that a loop may have to be unrolled. If a loop is unrolled,
-this parameter also determines how many times the loop code is unrolled.
-
-@item max-unroll-times
-The maximum number of unrollings of a single loop.
-
-@item max-peeled-insns
-The maximum number of instructions that a loop may have to be peeled.
-If a loop is peeled, this parameter also determines how many times
-the loop code is peeled.
-
-@item max-peel-times
-The maximum number of peelings of a single loop.
-
-@item max-peel-branches
-The maximum number of branches on the hot path through the peeled sequence.
-
-@item max-completely-peeled-insns
-The maximum number of insns of a completely peeled loop.
-
-@item max-completely-peel-times
-The maximum number of iterations of a loop to be suitable for complete peeling.
-
-@item max-completely-peel-loop-nest-depth
-The maximum depth of a loop nest suitable for complete peeling.
-
-@item max-unswitch-insns
-The maximum number of insns of an unswitched loop.
-
-@item max-unswitch-depth
-The maximum depth of a loop nest to be unswitched.
-
-@item lim-expensive
-The minimum cost of an expensive expression in the loop invariant motion.
-
-@item min-loop-cond-split-prob
-When FDO profile information is available, @option{min-loop-cond-split-prob}
-specifies minimum threshold for probability of semi-invariant condition
-statement to trigger loop split.
-
-@item iv-consider-all-candidates-bound
-Bound on number of candidates for induction variables, below which
-all candidates are considered for each use in induction variable
-optimizations. If there are more candidates than this,
-only the most relevant ones are considered to avoid quadratic time complexity.
-
-@item iv-max-considered-uses
-The induction variable optimizations give up on loops that contain more
-induction variable uses.
-
-@item iv-always-prune-cand-set-bound
-If the number of candidates in the set is smaller than this value,
-always try to remove unnecessary ivs from the set
-when adding a new one.
-
-@item avg-loop-niter
-Average number of iterations of a loop.
-
-@item dse-max-object-size
-Maximum size (in bytes) of objects tracked bytewise by dead store elimination.
-Larger values may result in larger compilation times.
-
-@item dse-max-alias-queries-per-store
-Maximum number of queries into the alias oracle per store.
-Larger values result in larger compilation times and may result in more
-removed dead stores.
-
-@item scev-max-expr-size
-Bound on size of expressions used in the scalar evolutions analyzer.
-Large expressions slow the analyzer.
-
-@item scev-max-expr-complexity
-Bound on the complexity of the expressions in the scalar evolutions analyzer.
-Complex expressions slow the analyzer.
-
-@item max-tree-if-conversion-phi-args
-Maximum number of arguments in a PHI supported by TREE if conversion
-unless the loop is marked with simd pragma.
-
-@item vect-max-layout-candidates
-The maximum number of possible vector layouts (such as permutations)
-to consider when optimizing to-be-vectorized code.
-
-@item vect-max-version-for-alignment-checks
-The maximum number of run-time checks that can be performed when
-doing loop versioning for alignment in the vectorizer.
-
-@item vect-max-version-for-alias-checks
-The maximum number of run-time checks that can be performed when
-doing loop versioning for alias in the vectorizer.
-
-@item vect-max-peeling-for-alignment
-The maximum number of loop peels to enhance access alignment
-for vectorizer. Value -1 means no limit.
-
-@item max-iterations-to-track
-The maximum number of iterations of a loop the brute-force algorithm
-for analysis of the number of iterations of the loop tries to evaluate.
-
-@item hot-bb-count-fraction
-The denominator n of fraction 1/n of the maximal execution count of a
-basic block in the entire program that a basic block needs to at least
-have in order to be considered hot. The default is 10000, which means
-that a basic block is considered hot if its execution count is greater
-than 1/10000 of the maximal execution count. 0 means that it is never
-considered hot. Used in non-LTO mode.
-
-@item hot-bb-count-ws-permille
-The number of most executed permilles, ranging from 0 to 1000, of the
-profiled execution of the entire program to which the execution count
-of a basic block must be part of in order to be considered hot. The
-default is 990, which means that a basic block is considered hot if
-its execution count contributes to the upper 990 permilles, or 99.0%,
-of the profiled execution of the entire program. 0 means that it is
-never considered hot. Used in LTO mode.
-
-@item hot-bb-frequency-fraction
-The denominator n of fraction 1/n of the execution frequency of the
-entry block of a function that a basic block of this function needs
-to at least have in order to be considered hot. The default is 1000,
-which means that a basic block is considered hot in a function if it
-is executed more frequently than 1/1000 of the frequency of the entry
-block of the function. 0 means that it is never considered hot.
-
-@item unlikely-bb-count-fraction
-The denominator n of fraction 1/n of the number of profiled runs of
-the entire program below which the execution count of a basic block
-must be in order for the basic block to be considered unlikely executed.
-The default is 20, which means that a basic block is considered unlikely
-executed if it is executed in fewer than 1/20, or 5%, of the runs of
-the program. 0 means that it is always considered unlikely executed.
-
-@item max-predicted-iterations
-The maximum number of loop iterations we predict statically. This is useful
-in cases where a function contains a single loop with known bound and
-another loop with unknown bound.
-The known number of iterations is predicted correctly, while
-the unknown number of iterations average to roughly 10. This means that the
-loop without bounds appears artificially cold relative to the other one.
-
-@item builtin-expect-probability
-Control the probability of the expression having the specified value. This
-parameter takes a percentage (i.e.@: 0 ... 100) as input.
-
-@item builtin-string-cmp-inline-length
-The maximum length of a constant string for a builtin string cmp call
-eligible for inlining.
-
-@item align-threshold
-
-Select fraction of the maximal frequency of executions of a basic block in
-a function to align the basic block.
-
-@item align-loop-iterations
-
-A loop expected to iterate at least the selected number of iterations is
-aligned.
-
-@item tracer-dynamic-coverage
-@itemx tracer-dynamic-coverage-feedback
-
-This value is used to limit superblock formation once the given percentage of
-executed instructions is covered. This limits unnecessary code size
-expansion.
-
-The @option{tracer-dynamic-coverage-feedback} parameter
-is used only when profile
-feedback is available. The real profiles (as opposed to statically estimated
-ones) are much less balanced allowing the threshold to be larger value.
-
-@item tracer-max-code-growth
-Stop tail duplication once code growth has reached given percentage. This is
-a rather artificial limit, as most of the duplicates are eliminated later in
-cross jumping, so it may be set to much higher values than is the desired code
-growth.
-
-@item tracer-min-branch-ratio
-
-Stop reverse growth when the reverse probability of best edge is less than this
-threshold (in percent).
-
-@item tracer-min-branch-probability
-@itemx tracer-min-branch-probability-feedback
-
-Stop forward growth if the best edge has probability lower than this
-threshold.
-
-Similarly to @option{tracer-dynamic-coverage} two parameters are
-provided. @option{tracer-min-branch-probability-feedback} is used for
-compilation with profile feedback and @option{tracer-min-branch-probability}
-compilation without. The value for compilation with profile feedback
-needs to be more conservative (higher) in order to make tracer
-effective.
-
-@item stack-clash-protection-guard-size
-Specify the size of the operating system provided stack guard as
-2 raised to @var{num} bytes. Higher values may reduce the
-number of explicit probes, but a value larger than the operating system
-provided guard will leave code vulnerable to stack clash style attacks.
-
-@item stack-clash-protection-probe-interval
-Stack clash protection involves probing stack space as it is allocated. This
-param controls the maximum distance between probes into the stack as 2 raised
-to @var{num} bytes. Higher values may reduce the number of explicit probes, but a value
-larger than the operating system provided guard will leave code vulnerable to
-stack clash style attacks.
-
-@item max-cse-path-length
-
-The maximum number of basic blocks on path that CSE considers.
-
-@item max-cse-insns
-The maximum number of instructions CSE processes before flushing.
-
-@item ggc-min-expand
-
-GCC uses a garbage collector to manage its own memory allocation. This
-parameter specifies the minimum percentage by which the garbage
-collector's heap should be allowed to expand between collections.
-Tuning this may improve compilation speed; it has no effect on code
-generation.
-
-The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when
-RAM >= 1GB@. If @code{getrlimit} is available, the notion of ``RAM'' is
-the smallest of actual RAM and @code{RLIMIT_DATA} or @code{RLIMIT_AS}. If
-GCC is not able to calculate RAM on a particular platform, the lower
-bound of 30% is used. Setting this parameter and
-@option{ggc-min-heapsize} to zero causes a full collection to occur at
-every opportunity. This is extremely slow, but can be useful for
-debugging.
-
-@item ggc-min-heapsize
-
-Minimum size of the garbage collector's heap before it begins bothering
-to collect garbage. The first collection occurs after the heap expands
-by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}. Again,
-tuning this may improve compilation speed, and has no effect on code
-generation.
-
-The default is the smaller of RAM/8, RLIMIT_RSS, or a limit that
-tries to ensure that RLIMIT_DATA or RLIMIT_AS are not exceeded, but
-with a lower bound of 4096 (four megabytes) and an upper bound of
-131072 (128 megabytes). If GCC is not able to calculate RAM on a
-particular platform, the lower bound is used. Setting this parameter
-very large effectively disables garbage collection. Setting this
-parameter and @option{ggc-min-expand} to zero causes a full collection
-to occur at every opportunity.
-
-@item max-reload-search-insns
-The maximum number of instruction reload should look backward for equivalent
-register. Increasing values mean more aggressive optimization, making the
-compilation time increase with probably slightly better performance.
-
-@item max-cselib-memory-locations
-The maximum number of memory locations cselib should take into account.
-Increasing values mean more aggressive optimization, making the compilation time
-increase with probably slightly better performance.
-
-@item max-sched-ready-insns
-The maximum number of instructions ready to be issued the scheduler should
-consider at any given time during the first scheduling pass. Increasing
-values mean more thorough searches, making the compilation time increase
-with probably little benefit.
-
-@item max-sched-region-blocks
-The maximum number of blocks in a region to be considered for
-interblock scheduling.
-
-@item max-pipeline-region-blocks
-The maximum number of blocks in a region to be considered for
-pipelining in the selective scheduler.
-
-@item max-sched-region-insns
-The maximum number of insns in a region to be considered for
-interblock scheduling.
-
-@item max-pipeline-region-insns
-The maximum number of insns in a region to be considered for
-pipelining in the selective scheduler.
-
-@item min-spec-prob
-The minimum probability (in percents) of reaching a source block
-for interblock speculative scheduling.
-
-@item max-sched-extend-regions-iters
-The maximum number of iterations through CFG to extend regions.
-A value of 0 disables region extensions.
-
-@item max-sched-insn-conflict-delay
-The maximum conflict delay for an insn to be considered for speculative motion.
-
-@item sched-spec-prob-cutoff
-The minimal probability of speculation success (in percents), so that
-speculative insns are scheduled.
-
-@item sched-state-edge-prob-cutoff
-The minimum probability an edge must have for the scheduler to save its
-state across it.
-
-@item sched-mem-true-dep-cost
-Minimal distance (in CPU cycles) between store and load targeting same
-memory locations.
-
-@item selsched-max-lookahead
-The maximum size of the lookahead window of selective scheduling. It is a
-depth of search for available instructions.
-
-@item selsched-max-sched-times
-The maximum number of times that an instruction is scheduled during
-selective scheduling. This is the limit on the number of iterations
-through which the instruction may be pipelined.
-
-@item selsched-insns-to-rename
-The maximum number of best instructions in the ready list that are considered
-for renaming in the selective scheduler.
-
-@item sms-min-sc
-The minimum value of stage count that swing modulo scheduler
-generates.
-
-@item max-last-value-rtl
-The maximum size measured as number of RTLs that can be recorded in an expression
-in combiner for a pseudo register as last known value of that register.
-
-@item max-combine-insns
-The maximum number of instructions the RTL combiner tries to combine.
-
-@item max-combine-search-insns
-The maximum number of instructions that the RTL combiner searches in order
-to find the next use of a given register definition. If this limit is reached
-without finding such a use, the combiner will stop trying to optimize the
-definition.
-
-Currently this limit only applies after certain successful combination
-attempts, but it could be extended to other cases in future.
-
-@item integer-share-limit
-Small integer constants can use a shared data structure, reducing the
-compiler's memory usage and increasing its speed. This sets the maximum
-value of a shared integer constant.
-
-@item ssp-buffer-size
-The minimum size of buffers (i.e.@: arrays) that receive stack smashing
-protection when @option{-fstack-protector} is used.
-
-@item min-size-for-stack-sharing
-The minimum size of variables taking part in stack slot sharing when not
-optimizing.
-
-@item max-jump-thread-duplication-stmts
-Maximum number of statements allowed in a block that needs to be
-duplicated when threading jumps.
-
-@item max-jump-thread-paths
-The maximum number of paths to consider when searching for jump threading
-opportunities. When arriving at a block, incoming edges are only considered
-if the number of paths to be searched so far multiplied by the number of
-incoming edges does not exhaust the specified maximum number of paths to
-consider.
-
-@item max-fields-for-field-sensitive
-Maximum number of fields in a structure treated in
-a field sensitive manner during pointer analysis.
-
-@item prefetch-latency
-Estimate on average number of instructions that are executed before
-prefetch finishes. The distance prefetched ahead is proportional
-to this constant. Increasing this number may also lead to less
-streams being prefetched (see @option{simultaneous-prefetches}).
-
-@item simultaneous-prefetches
-Maximum number of prefetches that can run at the same time.
-
-@item l1-cache-line-size
-The size of cache line in L1 data cache, in bytes.
-
-@item l1-cache-size
-The size of L1 data cache, in kilobytes.
-
-@item l2-cache-size
-The size of L2 data cache, in kilobytes.
-
-@item prefetch-dynamic-strides
-Whether the loop array prefetch pass should issue software prefetch hints
-for strides that are non-constant. In some cases this may be
-beneficial, though the fact the stride is non-constant may make it
-hard to predict when there is clear benefit to issuing these hints.
-
-Set to 1 if the prefetch hints should be issued for non-constant
-strides. Set to 0 if prefetch hints should be issued only for strides that
-are known to be constant and below @option{prefetch-minimum-stride}.
-
-@item prefetch-minimum-stride
-Minimum constant stride, in bytes, to start using prefetch hints for. If
-the stride is less than this threshold, prefetch hints will not be issued.
-
-This setting is useful for processors that have hardware prefetchers, in
-which case there may be conflicts between the hardware prefetchers and
-the software prefetchers. If the hardware prefetchers have a maximum
-stride they can handle, it should be used here to improve the use of
-software prefetchers.
-
-A value of -1 means we don't have a threshold and therefore
-prefetch hints can be issued for any constant stride.
-
-This setting is only useful for strides that are known and constant.
-
-@item destructive-interference-size
-@item constructive-interference-size
-The values for the C++17 variables
-@code{std::hardware_destructive_interference_size} and
-@code{std::hardware_constructive_interference_size}. The destructive
-interference size is the minimum recommended offset between two
-independent concurrently-accessed objects; the constructive
-interference size is the maximum recommended size of contiguous memory
-accessed together. Typically both will be the size of an L1 cache
-line for the target, in bytes. For a generic target covering a range of L1
-cache line sizes, typically the constructive interference size will be
-the small end of the range and the destructive size will be the large
-end.
-
-The destructive interference size is intended to be used for layout,
-and thus has ABI impact. The default value is not expected to be
-stable, and on some targets varies with @option{-mtune}, so use of
-this variable in a context where ABI stability is important, such as
-the public interface of a library, is strongly discouraged; if it is
-used in that context, users can stabilize the value using this
-option.
-
-The constructive interference size is less sensitive, as it is
-typically only used in a @samp{static_assert} to make sure that a type
-fits within a cache line.
-
-See also @option{-Winterference-size}.
-
-@item loop-interchange-max-num-stmts
-The maximum number of stmts in a loop to be interchanged.
-
-@item loop-interchange-stride-ratio
-The minimum ratio between stride of two loops for interchange to be profitable.
-
-@item min-insn-to-prefetch-ratio
-The minimum ratio between the number of instructions and the
-number of prefetches to enable prefetching in a loop.
-
-@item prefetch-min-insn-to-mem-ratio
-The minimum ratio between the number of instructions and the
-number of memory references to enable prefetching in a loop.
-
-@item use-canonical-types
-Whether the compiler should use the ``canonical'' type system.
-Should always be 1, which uses a more efficient internal
-mechanism for comparing types in C++ and Objective-C++. However, if
-bugs in the canonical type system are causing compilation failures,
-set this value to 0 to disable canonical types.
-
-@item switch-conversion-max-branch-ratio
-Switch initialization conversion refuses to create arrays that are
-bigger than @option{switch-conversion-max-branch-ratio} times the number of
-branches in the switch.
-
-@item max-partial-antic-length
-Maximum length of the partial antic set computed during the tree
-partial redundancy elimination optimization (@option{-ftree-pre}) when
-optimizing at @option{-O3} and above. For some sorts of source code
-the enhanced partial redundancy elimination optimization can run away,
-consuming all of the memory available on the host machine. This
-parameter sets a limit on the length of the sets that are computed,
-which prevents the runaway behavior. Setting a value of 0 for
-this parameter allows an unlimited set length.
-
-@item rpo-vn-max-loop-depth
-Maximum loop depth that is value-numbered optimistically.
-When the limit hits the innermost
-@var{rpo-vn-max-loop-depth} loops and the outermost loop in the
-loop nest are value-numbered optimistically and the remaining ones not.
-
-@item sccvn-max-alias-queries-per-access
-Maximum number of alias-oracle queries we perform when looking for
-redundancies for loads and stores. If this limit is hit the search
-is aborted and the load or store is not considered redundant. The
-number of queries is algorithmically limited to the number of
-stores on all paths from the load to the function entry.
-
-@item ira-max-loops-num
-IRA uses regional register allocation by default. If a function
-contains more loops than the number given by this parameter, only at most
-the given number of the most frequently-executed loops form regions
-for regional register allocation.
-
-@item ira-max-conflict-table-size
-Although IRA uses a sophisticated algorithm to compress the conflict
-table, the table can still require excessive amounts of memory for
-huge functions. If the conflict table for a function could be more
-than the size in MB given by this parameter, the register allocator
-instead uses a faster, simpler, and lower-quality
-algorithm that does not require building a pseudo-register conflict table.
-
-@item ira-loop-reserved-regs
-IRA can be used to evaluate more accurate register pressure in loops
-for decisions to move loop invariants (see @option{-O3}). The number
-of available registers reserved for some other purposes is given
-by this parameter. Default of the parameter
-is the best found from numerous experiments.
-
-@item ira-consider-dup-in-all-alts
-Make IRA to consider matching constraint (duplicated operand number)
-heavily in all available alternatives for preferred register class.
-If it is set as zero, it means IRA only respects the matching
-constraint when it's in the only available alternative with an
-appropriate register class. Otherwise, it means IRA will check all
-available alternatives for preferred register class even if it has
-found some choice with an appropriate register class and respect the
-found qualified matching constraint.
-
-@item ira-simple-lra-insn-threshold
-Approximate function insn number in 1K units triggering simple local RA.
-
-@item lra-inheritance-ebb-probability-cutoff
-LRA tries to reuse values reloaded in registers in subsequent insns.
-This optimization is called inheritance. EBB is used as a region to
-do this optimization. The parameter defines a minimal fall-through
-edge probability in percentage used to add BB to inheritance EBB in
-LRA. The default value was chosen
-from numerous runs of SPEC2000 on x86-64.
-
-@item loop-invariant-max-bbs-in-loop
-Loop invariant motion can be very expensive, both in compilation time and
-in amount of needed compile-time memory, with very large loops. Loops
-with more basic blocks than this parameter won't have loop invariant
-motion optimization performed on them.
-
-@item loop-max-datarefs-for-datadeps
-Building data dependencies is expensive for very large loops. This
-parameter limits the number of data references in loops that are
-considered for data dependence analysis. These large loops are no
-handled by the optimizations using loop data dependencies.
-
-@item max-vartrack-size
-Sets a maximum number of hash table slots to use during variable
-tracking dataflow analysis of any function. If this limit is exceeded
-with variable tracking at assignments enabled, analysis for that
-function is retried without it, after removing all debug insns from
-the function. If the limit is exceeded even without debug insns, var
-tracking analysis is completely disabled for the function. Setting
-the parameter to zero makes it unlimited.
-
-@item max-vartrack-expr-depth
-Sets a maximum number of recursion levels when attempting to map
-variable names or debug temporaries to value expressions. This trades
-compilation time for more complete debug information. If this is set too
-low, value expressions that are available and could be represented in
-debug information may end up not being used; setting this higher may
-enable the compiler to find more complex debug expressions, but compile
-time and memory use may grow.
-
-@item max-debug-marker-count
-Sets a threshold on the number of debug markers (e.g.@: begin stmt
-markers) to avoid complexity explosion at inlining or expanding to RTL.
-If a function has more such gimple stmts than the set limit, such stmts
-will be dropped from the inlined copy of a function, and from its RTL
-expansion.
-
-@item min-nondebug-insn-uid
-Use uids starting at this parameter for nondebug insns. The range below
-the parameter is reserved exclusively for debug insns created by
-@option{-fvar-tracking-assignments}, but debug insns may get
-(non-overlapping) uids above it if the reserved range is exhausted.
-
-@item ipa-sra-deref-prob-threshold
-IPA-SRA replaces a pointer which is known not be NULL with one or more
-new parameters only when the probability (in percent, relative to
-function entry) of it being dereferenced is higher than this parameter.
-
-@item ipa-sra-ptr-growth-factor
-IPA-SRA replaces a pointer to an aggregate with one or more new
-parameters only when their cumulative size is less or equal to
-@option{ipa-sra-ptr-growth-factor} times the size of the original
-pointer parameter.
-
-@item ipa-sra-ptrwrap-growth-factor
-Additional maximum allowed growth of total size of new parameters
-that ipa-sra replaces a pointer to an aggregate with,
-if it points to a local variable that the caller only writes to and
-passes it as an argument to other functions.
-
-@item ipa-sra-max-replacements
-Maximum pieces of an aggregate that IPA-SRA tracks. As a
-consequence, it is also the maximum number of replacements of a formal
-parameter.
-
-@item sra-max-scalarization-size-Ospeed
-@itemx sra-max-scalarization-size-Osize
-The two Scalar Reduction of Aggregates passes (SRA and IPA-SRA) aim to
-replace scalar parts of aggregates with uses of independent scalar
-variables. These parameters control the maximum size, in storage units,
-of aggregate which is considered for replacement when compiling for
-speed
-(@option{sra-max-scalarization-size-Ospeed}) or size
-(@option{sra-max-scalarization-size-Osize}) respectively.
-
-@item sra-max-propagations
-The maximum number of artificial accesses that Scalar Replacement of
-Aggregates (SRA) will track, per one local variable, in order to
-facilitate copy propagation.
-
-@item tm-max-aggregate-size
-When making copies of thread-local variables in a transaction, this
-parameter specifies the size in bytes after which variables are
-saved with the logging functions as opposed to save/restore code
-sequence pairs. This option only applies when using
-@option{-fgnu-tm}.
-
-@item graphite-max-nb-scop-params
-To avoid exponential effects in the Graphite loop transforms, the
-number of parameters in a Static Control Part (SCoP) is bounded.
-A value of zero can be used to lift
-the bound. A variable whose value is unknown at compilation time and
-defined outside a SCoP is a parameter of the SCoP.
-
-@item hardcfr-max-blocks
-Disable @option{-fharden-control-flow-redundancy} for functions with a
-larger number of blocks than the specified value. Zero removes any
-limit.
-
-@item hardcfr-max-inline-blocks
-Force @option{-fharden-control-flow-redundancy} to use out-of-line
-checking for functions with a larger number of basic blocks than the
-specified value.
-
-@item loop-block-tile-size
-Loop blocking or strip mining transforms, enabled with
-@option{-floop-block} or @option{-floop-strip-mine}, strip mine each
-loop in the loop nest by a given number of iterations. The strip
-length can be changed using the @option{loop-block-tile-size}
-parameter.
-
-@item ipa-jump-function-lookups
-Specifies number of statements visited during jump function offset discovery.
-
-@item ipa-cp-value-list-size
-IPA-CP attempts to track all possible values and types passed to a function's
-parameter in order to propagate them and perform devirtualization.
-@option{ipa-cp-value-list-size} is the maximum number of values and types it
-stores per one formal parameter of a function.
-
-@item ipa-cp-eval-threshold
-IPA-CP calculates its own score of cloning profitability heuristics
-and performs those cloning opportunities with scores that exceed
-@option{ipa-cp-eval-threshold}.
-
-@item ipa-cp-max-recursive-depth
-Maximum depth of recursive cloning for self-recursive function.
-
-@item ipa-cp-min-recursive-probability
-Recursive cloning only when the probability of call being executed exceeds
-the parameter.
-
-@item ipa-cp-recursive-freq-factor
-The number of times interprocedural copy propagation expects recursive
-functions to call themselves.
-
-@item ipa-cp-recursion-penalty
-Percentage penalty the recursive functions will receive when they
-are evaluated for cloning.
-
-@item ipa-cp-single-call-penalty
-Percentage penalty functions containing a single call to another
-function will receive when they are evaluated for cloning.
-
-@item ipa-cp-sweeps
-The number of times the interprocedural constant propagation will traverse
-all functions to make cloning decisions.
-
-@item ipa-max-agg-items
-IPA-CP is also capable to propagate a number of scalar values passed
-in an aggregate. @option{ipa-max-agg-items} controls the maximum
-number of such values per one parameter.
-
-@item ipa-cp-loop-hint-bonus
-When IPA-CP determines that a cloning candidate would make the number
-of iterations of a loop known, it adds a bonus of
-@option{ipa-cp-loop-hint-bonus} to the profitability score of
-the candidate.
-
-@item ipa-max-loop-predicates
-The maximum number of different predicates IPA will use to describe when
-loops in a function have known properties.
-
-@item ipa-max-aa-steps
-During its analysis of function bodies, IPA-CP employs alias analysis
-in order to track values pointed to by function parameters. In order
-not spend too much time analyzing huge functions, it gives up and
-consider all memory clobbered after examining
-@option{ipa-max-aa-steps} statements modifying memory.
-
-@item ipa-max-switch-predicate-bounds
-Maximal number of boundary endpoints of case ranges of switch statement.
-For switch exceeding this limit, IPA-CP will not construct cloning cost
-predicate, which is used to estimate cloning benefit, for default case
-of the switch statement.
-
-@item ipa-max-param-expr-ops
-IPA-CP will analyze conditional statement that references some function
-parameter to estimate benefit for cloning upon certain constant value.
-But if number of operations in a parameter expression exceeds
-@option{ipa-max-param-expr-ops}, the expression is treated as complicated
-one, and is not handled by IPA analysis.
-
-@item lto-partitions
-Specify desired number of partitions produced during WHOPR compilation.
-The number of partitions should exceed the number of CPUs used for compilation.
-
-@item lto-min-partition
-Size of minimal partition for WHOPR (in estimated instructions).
-This prevents expenses of splitting very small programs into too many
-partitions.
-
-@item lto-max-partition
-Size of max partition for WHOPR (in estimated instructions).
-to provide an upper bound for individual size of partition.
-Meant to be used only with balanced partitioning.
-
-@item lto-partition-locality-frequency-cutoff
-The denominator n of fraction 1/n of the execution frequency of callee to be
-cloned for a particular caller. Special value of 0 dictates to always clone
-without a cut-off.
-
-@item lto-partition-locality-size-cutoff
-Size cut-off for callee including inlined calls to be cloned for a particular
-caller.
-
-@item lto-max-locality-partition
-Maximal size of a locality partition for LTO (in estimated instructions).
-Value of 0 results in default value being used.
-
-@item lto-max-streaming-parallelism
-Maximal number of parallel processes used for LTO streaming.
-
-@item cxx-max-namespaces-for-diagnostic-help
-The maximum number of namespaces to consult for suggestions when C++
-name lookup fails for an identifier.
-
-@item sink-frequency-threshold
-The maximum relative execution frequency (in percents) of the target block
-relative to a statement's original block to allow statement sinking of a
-statement. Larger numbers result in more aggressive statement sinking.
-A small positive adjustment is applied for
-statements with memory operands as those are even more profitable so sink.
-
-@item max-stores-to-sink
-The maximum number of conditional store pairs that can be sunk. Set to 0
-if either vectorization (@option{-ftree-vectorize}) or if-conversion
-(@option{-ftree-loop-if-convert}) is disabled.
-
-@item case-values-threshold
-The smallest number of different values for which it is best to use a
-jump-table instead of a tree of conditional branches. If the value is
-0, use the default for the machine.
-
-@item jump-table-max-growth-ratio-for-size
-The maximum code size growth ratio when expanding
-into a jump table (in percent). The parameter is used when
-optimizing for size.
-
-@item jump-table-max-growth-ratio-for-speed
-The maximum code size growth ratio when expanding
-into a jump table (in percent). The parameter is used when
-optimizing for speed.
-
-@item tree-reassoc-width
-Set the maximum number of instructions executed in parallel in
-reassociated tree. This parameter overrides target dependent
-heuristics used by default if has non zero value.
-
-@item sched-pressure-algorithm
-Choose between the two available implementations of
-@option{-fsched-pressure}. Algorithm 1 is the original implementation
-and is the more likely to prevent instructions from being reordered.
-Algorithm 2 was designed to be a compromise between the relatively
-conservative approach taken by algorithm 1 and the rather aggressive
-approach taken by the default scheduler. It relies more heavily on
-having a regular register file and accurate register pressure classes.
-See @file{haifa-sched.cc} in the GCC sources for more details.
-
-The default choice depends on the target.
-
-@item max-slsr-cand-scan
-Set the maximum number of existing candidates that are considered when
-seeking a basis for a new straight-line strength reduction candidate.
-
-@item asan-globals
-Enable buffer overflow detection for global objects. This kind
-of protection is enabled by default if you are using
-@option{-fsanitize=address} option.
-To disable global objects protection use @option{--param asan-globals=0}.
-
-@item asan-stack
-Enable buffer overflow detection for stack objects. This kind of
-protection is enabled by default when using @option{-fsanitize=address}.
-To disable stack protection use @option{--param asan-stack=0} option.
-
-@item asan-instrument-reads
-Enable buffer overflow detection for memory reads. This kind of
-protection is enabled by default when using @option{-fsanitize=address}.
-To disable memory reads protection use
-@option{--param asan-instrument-reads=0}.
-
-@item asan-instrument-writes
-Enable buffer overflow detection for memory writes. This kind of
-protection is enabled by default when using @option{-fsanitize=address}.
-To disable memory writes protection use
-@option{--param asan-instrument-writes=0} option.
-
-@item asan-memintrin
-Enable detection for built-in functions. This kind of protection
-is enabled by default when using @option{-fsanitize=address}.
-To disable built-in functions protection use
-@option{--param asan-memintrin=0}.
-
-@item asan-use-after-return
-Enable detection of use-after-return. This kind of protection
-is enabled by default when using the @option{-fsanitize=address} option.
-To disable it use @option{--param asan-use-after-return=0}.
-
-Note: By default the check is disabled at run time. To enable it,
-add @code{detect_stack_use_after_return=1} to the environment variable
-@env{ASAN_OPTIONS}.
-
-@item asan-instrumentation-with-call-threshold
-If number of memory accesses in function being instrumented
-is greater or equal to this number, use callbacks instead of inline checks.
-E.g. to disable inline code use
-@option{--param asan-instrumentation-with-call-threshold=0}.
-
-@item asan-kernel-mem-intrinsic-prefix
-If nonzero, prefix calls to @code{memcpy}, @code{memset} and @code{memmove}
-with @samp{__asan_} or @samp{__hwasan_}
-for @option{-fsanitize=kernel-address} or @samp{-fsanitize=kernel-hwaddress},
-respectively.
-
-@item hwasan-instrument-stack
-Enable hwasan instrumentation of statically sized stack-allocated variables.
-This kind of instrumentation is enabled by default when using
-@option{-fsanitize=hwaddress} and disabled by default when using
-@option{-fsanitize=kernel-hwaddress}.
-To disable stack instrumentation use
-@option{--param hwasan-instrument-stack=0}, and to enable it use
-@option{--param hwasan-instrument-stack=1}.
-
-@item hwasan-random-frame-tag
-When using stack instrumentation, decide tags for stack variables using a
-deterministic sequence beginning at a random tag for each frame. With this
-parameter unset tags are chosen using the same sequence but beginning from 1.
-This is enabled by default for @option{-fsanitize=hwaddress} and unavailable
-for @option{-fsanitize=kernel-hwaddress} and @option{-fsanitize=memtag-stack}.
-To disable it use @option{--param hwasan-random-frame-tag=0}.
-
-@item hwasan-instrument-allocas
-Enable hwasan instrumentation of dynamically sized stack-allocated variables.
-This kind of instrumentation is enabled by default when using
-@option{-fsanitize=hwaddress} and disabled by default when using
-@option{-fsanitize=kernel-hwaddress}.
-To disable instrumentation of such variables use
-@option{--param hwasan-instrument-allocas=0}, and to enable it use
-@option{--param hwasan-instrument-allocas=1}.
-
-@item hwasan-instrument-reads
-Enable hwasan checks on memory reads. Instrumentation of reads is enabled by
-default for both @option{-fsanitize=hwaddress} and
-@option{-fsanitize=kernel-hwaddress}.
-To disable checking memory reads use
-@option{--param hwasan-instrument-reads=0}.
-
-@item hwasan-instrument-writes
-Enable hwasan checks on memory writes. Instrumentation of writes is enabled by
-default for both @option{-fsanitize=hwaddress} and
-@option{-fsanitize=kernel-hwaddress}.
-To disable checking memory writes use
-@option{--param hwasan-instrument-writes=0}.
-
-@item hwasan-instrument-mem-intrinsics
-Enable hwasan instrumentation of builtin functions. Instrumentation of these
-builtin functions is enabled by default for both @option{-fsanitize=hwaddress}
-and @option{-fsanitize=kernel-hwaddress}.
-To disable instrumentation of builtin functions use
-@option{--param hwasan-instrument-mem-intrinsics=0}.
-
-@item memtag-instrument-allocas
-Enable hardware-assisted memory tagging of dynamically sized stack-allocated
-variables. This kind of code generation is enabled by default when using
-@option{-fsanitize=memtag-stack}.
-
-@item memtag-instrument-mem-intrinsics
-When sanitizing using MTE instructions, include builtin functions.
-
-@item use-after-scope-direct-emission-threshold
-If the size of a local variable in bytes is smaller or equal to this
-number, directly poison (or unpoison) shadow memory instead of using
-run-time callbacks.
-
-@item tsan-distinguish-volatile
-Emit special instrumentation for accesses to volatiles.
-
-@item tsan-instrument-func-entry-exit
-Emit instrumentation calls to __tsan_func_entry() and __tsan_func_exit().
-
-@item max-fsm-thread-path-insns
-Maximum number of instructions to copy when duplicating blocks on a
-finite state automaton jump thread path.
-
-@item threader-debug
-threader-debug=[none|all] Enables verbose dumping of the threader solver.
-
-@item parloops-chunk-size
-Chunk size of omp schedule for loops parallelized by parloops.
-
-@item parloops-schedule
-Schedule type of omp schedule for loops parallelized by parloops (static,
-dynamic, guided, auto, runtime).
-
-@item parloops-min-per-thread
-The minimum number of iterations per thread of an innermost parallelized
-loop for which the parallelized variant is preferred over the single threaded
-one. Note that for a parallelized loop nest the
-minimum number of iterations of the outermost loop per thread is two.
-
-@item max-ssa-name-query-depth
-Maximum depth of recursion when querying properties of SSA names in things
-like fold routines. One level of recursion corresponds to following a
-use-def chain.
-
-@item max-speculative-devirt-maydefs
-The maximum number of may-defs we analyze when looking for a must-def
-specifying the dynamic type of an object that invokes a virtual call
-we may be able to devirtualize speculatively.
-
-@item ranger-debug
-Specifies the type of debug output to be issued for ranges.
-
-@item unroll-jam-min-percent
-The minimum percentage of memory references that must be optimized
-away for the unroll-and-jam transformation to be considered profitable.
-
-@item unroll-jam-max-unroll
-The maximum number of times the outer loop should be unrolled by
-the unroll-and-jam transformation.
-
-@item max-rtl-if-conversion-unpredictable-cost
-Maximum permissible cost for the sequence that would be generated
-by the RTL if-conversion pass for a branch that is considered unpredictable.
-
-@item max-variable-expansions-in-unroller
-If @option{-fvariable-expansion-in-unroller} is used, the maximum number
-of times that an individual variable will be expanded during loop unrolling.
-
-@item partial-inlining-entry-probability
-Maximum probability of the entry BB of split region
-(in percent relative to entry BB of the function)
-to make partial inlining happen.
-
-@item max-tracked-strlens
-Maximum number of strings for which strlen optimization pass will
-track string lengths.
-
-@item gcse-after-reload-partial-fraction
-The threshold ratio for performing partial redundancy
-elimination after reload.
-
-@item gcse-after-reload-critical-fraction
-The threshold ratio of critical edges execution count that
-permit performing redundancy elimination after reload.
-
-@item max-loop-header-insns
-The maximum number of insns in loop header duplicated
-by the copy loop headers pass.
-
-@item vect-epilogues-nomask
-Enable loop epilogue vectorization using smaller vector size.
-
-@item vect-partial-vector-usage
-Controls when the loop vectorizer considers using partial vector loads
-and stores as an alternative to falling back to scalar code. 0 stops
-the vectorizer from ever using partial vector loads and stores. 1 allows
-partial vector loads and stores if vectorization removes the need for the
-code to iterate. 2 allows partial vector loads and stores in all loops.
-The parameter only has an effect on targets that support partial
-vector loads and stores.
-
-@item vect-inner-loop-cost-factor
-The maximum factor which the loop vectorizer applies to the cost of statements
-in an inner loop relative to the loop being vectorized. The factor applied
-is the maximum of the estimated number of iterations of the inner loop and
-this parameter. The default value of this parameter is 50.
-
-@item vect-induction-float
-Enable loop vectorization of floating point inductions.
-
-@item vect-scalar-cost-multiplier
-Apply the given multiplier % to scalar loop costing during vectorization.
-Increasing the cost multiplier will make vector loops more profitable.
-
-@item vrp-block-limit
-Maximum number of basic blocks before VRP switches to a lower memory algorithm.
-
-@item vrp-cstload-limit
-Maximum number of steps when inferring a value range from a load from a constant aggregate.
-
-@item vrp-sparse-threshold
-Maximum number of basic blocks before VRP uses a sparse bitmap cache.
-
-@item vrp-switch-limit
-Maximum number of outgoing edges in a switch before VRP will not process it.
-
-@item vrp-vector-threshold
-Maximum number of basic blocks for VRP to use a basic cache vector.
-
-@item avoid-fma-max-bits
-Maximum number of bits for which we avoid creating FMAs.
-
-@item fully-pipelined-fma
-Whether the target fully pipelines FMA instructions. If non-zero,
-reassociation considers the benefit of parallelizing FMA's multiplication
-part and addition part, assuming FMUL and FMA use the same units that can
-also do FADD.
-
-@item sms-loop-average-count-threshold
-A threshold on the average loop count considered by the swing modulo scheduler.
-
-@item sms-dfa-history
-The number of cycles the swing modulo scheduler considers when checking
-conflicts using DFA.
-
-@item graphite-allow-codegen-errors
-Whether codegen errors should be ICEs when @option{-fchecking}.
-
-@item sms-max-ii-factor
-A factor for tuning the upper bound that swing modulo scheduler
-uses for scheduling a loop.
-
-@item lra-max-considered-reload-pseudos
-The max number of reload pseudos which are considered during
-spilling a non-reload pseudo.
-
-@item lra-max-pseudos-points-log2-considered-for-preferences
-The maximum @code{log2(number of reload pseudos * number of
-program points)} threshold when preferences for other reload pseudos
-are still considered. Taking these preferences into account helps to
-improve register allocation. However, for very large functions, a
-large value can result in significant compilation time and memory
-consumption. The default value is 30.
-
-@item max-pow-sqrt-depth
-Maximum depth of sqrt chains to use when synthesizing exponentiation
-by a real constant.
-
-@item max-dse-active-local-stores
-Maximum number of active local stores in RTL dead store elimination.
-
-@item asan-instrument-allocas
-Enable asan allocas/VLAs protection.
-
-@item max-iterations-computation-cost
-Bound on the cost of an expression to compute the number of iterations.
-
-@item max-isl-operations
-Maximum number of isl operations, 0 means unlimited.
-
-@item graphite-max-arrays-per-scop
-Maximum number of arrays per scop.
-
-@item max-vartrack-reverse-op-size
-Max. size of loc list for which reverse ops should be added.
-
-@item fsm-scale-path-stmts
-Scale factor to apply to the number of statements in a threading path
-crossing a loop backedge when comparing to
-@option{--param=max-jump-thread-duplication-stmts}.
-
-@item uninit-control-dep-attempts
-Maximum number of nested calls to search for control dependencies
-during uninitialized variable analysis.
-
-@item uninit-max-chain-len
-Maximum number of predicates anded for each predicate ored in the normalized
-predicate chain.
-
-@item uninit-max-num-chains
-Maximum number of predicates ored in the normalized predicate chain.
-
-@item uninit-max-prune-work
-Maximum amount of work done to prune paths where the variable is always initialized.
-
-@item sched-autopref-queue-depth
-Hardware autoprefetcher scheduler model control flag.
-Number of lookahead cycles the model looks into; at '
-' only enable instruction sorting heuristic.
-
-@item loop-versioning-max-inner-insns
-The maximum number of instructions that an inner loop can have
-before the loop versioning pass considers it too big to copy.
-
-@item loop-versioning-max-outer-insns
-The maximum number of instructions that an outer loop can have
-before the loop versioning pass considers it too big to copy,
-discounting any instructions in inner loops that directly benefit
-from versioning.
-
-@item ssa-name-def-chain-limit
-The maximum number of SSA_NAME assignments to follow in determining
-a property of a variable such as its value. This limits the number
-of iterations or recursive calls GCC performs when optimizing certain
-statements or when determining their validity prior to issuing
-diagnostics.
-
-@item store-merging-max-size
-Maximum size of a single store merging region in bytes.
-
-@item store-forwarding-max-distance
-Maximum number of instruction distance that a small store forwarded to a larger
-load may stall. Value '0' disables the cost checks for the
-avoid-store-forwarding pass.
-
-@item hash-table-verification-limit
-The number of elements for which hash table verification is done
-for each searched element.
-
-@item max-find-base-term-values
-Maximum number of VALUEs handled during a single find_base_term call.
-
-@item analyzer-max-enodes-per-program-point
-The maximum number of exploded nodes per program point within
-the analyzer, before terminating analysis of that point.
-
-@item analyzer-max-constraints
-The maximum number of constraints per state.
-
-@item analyzer-min-snodes-for-call-summary
-The minimum number of supernodes within a function for the
-analyzer to consider summarizing its effects at call sites.
-
-@item analyzer-max-enodes-for-full-dump
-The maximum depth of exploded nodes that should appear in a dot dump
-before switching to a less verbose format.
-
-@item analyzer-max-recursion-depth
-The maximum number of times a callsite can appear in a call stack
-within the analyzer, before terminating analysis of a call that would
-recurse deeper.
-
-@item analyzer-max-svalue-depth
-The maximum depth of a symbolic value, before approximating
-the value as unknown.
-
-@item analyzer-max-infeasible-edges
-The maximum number of infeasible edges to reject before declaring
-a diagnostic as infeasible.
-
-@item gimple-fe-computed-hot-bb-threshold
-The number of executions of a basic block which is considered hot.
-The parameter is used only in GIMPLE FE.
-
-@item analyzer-bb-explosion-factor
-The maximum number of 'after supernode' exploded nodes within the analyzer
-per supernode, before terminating analysis.
-
-@item analyzer-text-art-string-ellipsis-threshold
-The number of bytes at which to ellipsize string literals in analyzer text art diagrams.
-
-@item analyzer-text-art-ideal-canvas-width
-The ideal width in characters of text art diagrams generated by the analyzer.
-
-@item analyzer-text-art-string-ellipsis-head-len
-The number of literal bytes to show at the head of a string literal in text art when ellipsizing it.
-
-@item analyzer-text-art-string-ellipsis-tail-len
-The number of literal bytes to show at the tail of a string literal in text art when ellipsizing it.
-
-@item ranger-logical-depth
-Maximum depth of logical expression evaluation ranger will look through
-when evaluating outgoing edge ranges.
-
-@item ranger-recompute-depth
-Maximum depth of instruction chains to consider for recomputation
-in the outgoing range calculator.
-
-@item relation-block-limit
-Maximum number of relations the oracle will register in a basic block.
-
-@item transitive-relations-work-bound
-Work bound when discovering transitive relations from existing relations.
-
-@item min-pagesize
-Minimum page size for warning and early break vectorization purposes.
-
-@item openacc-kernels
-Specify mode of OpenACC `kernels' constructs handling.
-With @option{--param=openacc-kernels=decompose}, OpenACC `kernels'
-constructs are decomposed into parts, a sequence of compute
-constructs, each then handled individually.
-This is work in progress.
-With @option{--param=openacc-kernels=parloops}, OpenACC `kernels'
-constructs are handled by the @samp{parloops} pass, en bloc.
-This is the current default.
-
-@item openacc-privatization
-Control whether the @option{-fopt-info-omp-note} and applicable
-@option{-fdump-tree-*-details} options emit OpenACC privatization diagnostics.
-With @option{--param=openacc-privatization=quiet}, don't diagnose.
-This is the current default.
-With @option{--param=openacc-privatization=noisy}, do diagnose.
-
-@item cycle-accurate-model
-Specifies whether GCC should assume that the scheduling description is mostly
-a cycle-accurate model of the target processor the code is intended to
-run on, in the absence of cache misses. Nonzero means that the selected
-scheduling model is accurate and likely describes an in-order processor,
-and that scheduling should aggressively spill to try and fill any pipeline
-bubbles. This is the current default. Zero means the scheduling description
-might not be available/accurate or perhaps not applicable at all, such as for
-modern out-of-order processors.
-
-@end table
-
-The following choices of @var{name} are available on AArch64 targets:
-
-@table @gcctabopt
-@item aarch64-vect-compare-costs
-When vectorizing, consider using multiple different approaches and use
-the cost model to choose the cheapest one. This includes:
-
-@itemize
-@item
-Trying both SVE and Advanced SIMD, when SVE is available.
-
-@item
-Trying to use 64-bit Advanced SIMD vectors for the smallest data elements,
-rather than using 128-bit vectors for everything.
-
-@item
-Trying to use ``unpacked'' SVE vectors for smaller elements. This includes
-storing smaller elements in larger containers and accessing elements with
-extending loads and truncating stores.
-@end itemize
-
-@item aarch64-float-recp-precision
-The number of Newton iterations for calculating the reciprocal for float type.
-The precision of division is proportional to this param when division
-approximation is enabled. The default value is 1.
-
-@item aarch64-double-recp-precision
-The number of Newton iterations for calculating the reciprocal for double type.
-The precision of division is proportional to this param when division
-approximation is enabled. The default value is 2.
-
-@item aarch64-autovec-preference
-An old alias for @option{-mautovec-preference}. If both
-@option{-mautovec-preference} and @option{--param=aarch64-autovec-preference}
-are passed, the @option{--param} value will be used.
-
-@item aarch64-ldp-policy
-Fine-grained policy for load pairs.
-With @option{--param=aarch64-ldp-policy=default}, use the policy of the
-tuning structure. This is the current default.
-With @option{--param=aarch64-ldp-policy=always}, emit ldp regardless
-of alignment.
-With @option{--param=aarch64-ldp-policy=never}, do not emit ldp.
-With @option{--param=aarch64-ldp-policy=aligned}, emit ldp only if the
-source pointer is aligned to at least double the alignment of the type.
-
-@item aarch64-stp-policy
-Fine-grained policy for store pairs.
-With @option{--param=aarch64-stp-policy=default}, use the policy of the
-tuning structure. This is the current default.
-With @option{--param=aarch64-stp-policy=always}, emit stp regardless
-of alignment.
-With @option{--param=aarch64-stp-policy=never}, do not emit stp.
-With @option{--param=aarch64-stp-policy=aligned}, emit stp only if the
-source pointer is aligned to at least double the alignment of the type.
-
-@item aarch64-ldp-alias-check-limit
-Limit on the number of alias checks performed by the AArch64 load/store pair
-fusion pass when attempting to form an ldp/stp. Higher values make the pass
-more aggressive at re-ordering loads over stores, at the expense of increased
-compile time.
-
-@item aarch64-ldp-writeback
-Param to control which writeback opportunities we try to handle in the AArch64
-load/store pair fusion pass. A value of zero disables writeback handling. One
-means we try to form pairs involving one or more existing individual writeback
-accesses where possible. A value of two means we also try to opportunistically
-form writeback opportunities by folding in trailing destructive updates of the
-base register used by a pair.
-
-@item aarch64-loop-vect-issue-rate-niters
-The tuning for some AArch64 CPUs tries to take both latencies and issue
-rates into account when deciding whether a loop should be vectorized
-using SVE, vectorized using Advanced SIMD, or not vectorized at all.
-If this parameter is set to @var{n}, GCC will not use this heuristic
-for loops that are known to execute in fewer than @var{n} Advanced
-SIMD iterations.
-
-@item aarch64-vect-unroll-limit
-The vectorizer will use available tuning information to determine whether it
-would be beneficial to unroll the main vectorized loop and by how much. This
-parameter set's the upper bound of how much the vectorizer will unroll the main
-loop. The default value is four.
-
-@item aarch64-tag-memory-loop-threshold
-Param to control the treshold in number of granules beyond which an
-explicit loop for tagging a memory block is emitted. The memory block
-is tagged using MTE instructions.
-
-@end table
-
-The following choices of @var{name} are available on GCN targets:
-
-@table @gcctabopt
-@item gcn-preferred-vectorization-factor
-Preferred vectorization factor: @samp{default}, @samp{32}, @samp{64}.
-
-@end table
-
-The following choices of @var{name} are available on i386 and x86_64 targets:
-
-@table @gcctabopt
-@item x86-stlf-window-ninsns
-Instructions number above which STFL stall penalty can be compensated.
-
-@item x86-stv-max-visits
-The maximum number of use and def visits when discovering a STV chain before
-the discovery is aborted.
-
-@item ix86-vect-unroll-limit
-Limit how much the autovectorizer may unroll a loop.
-
-@item ix86-vect-compare-costs
-Whether x86 vectorizer cost modeling compares costs of different vector sizes.
-
-@end table
-
@end table
@node Instrumentation Options
@item -dumpspecs
Print the compiler's built-in specs---and don't do anything else. (This
is used when GCC itself is being built.) @xref{Spec Files}.
+
+@opindex param
+@item --param @var{name}=@var{value}
+@itemx --param=@var{name}=@var{value}
+GCC by convention uses parameters that can be specified on the command
+line instead of hard-wired constants to represent arbitrary compiler
+limits or heuristics. Many parameters are related to optimization;
+for example, GCC does not inline functions that contain more than a
+certain number of instructions. The static analyzer similarly uses
+parameters to limit complexity, link-time optimization uses parameters
+to control partitioning, and so on. Other parameters control aspects
+of GCC that are completely internal, such as its memory allocation and
+garbage collection strategy. Still others control target-specific
+behavior.
+
+The @option{--param} option provides a uniform interface for
+specifying values for these compiler parameters. However, the names
+of specific parameters, and the meaning of the values, are tied to the
+internals of the compiler, and are subject to change without notice in
+future releases. You should not depend on parameter settings for
+correct compilation of your program. They are exposed via the command
+line for the convenience of developers in debugging compilation
+problems or, in some cases, to provide workarounds for compiler bugs.
+
+@xref{Parameters,,Parameters,gccint,GNU Compiler Collection (GCC) Internals},
+for documentation of these internal parameters.
@end table
@node Submodel Options
need the annotation to analyze the control flow. The default is
@option{-mno-annotate-tablejump}.
-@item --param loongarch-vect-unroll-limit=@var{n}
-The vectorizer uses available tuning information to determine whether it
-would be beneficial to unroll the main vectorized loop and by how much. This
-parameter sets the upper bound of how much the vectorizer unrolls the main
-loop. The default value is six.
-
@end table
@node LynxOS Options
and instructions for accelerated processing are available.
The default is to inline @code{strcmp} calls.
-The @option{--param riscv-strcmp-inline-limit=@var{n}} parameter controls
-the maximum number of bytes compared by the inlined code.
-The default value is 64.
-
@opindex minline-strncmp
@opindex mno-inline-strncmp
@item -minline-strncmp
and instructions for accelerated processing are available.
The default is to inline @code{strncmp} calls.
-The @option{--param riscv-strcmp-inline-limit=@var{n}} parameter controls
-the maximum number of bytes compared by the inlined code.
-The default value is 64.
-
@opindex mstringop-strategy
@item -mstringop-strategy=@var{strategy}
Specify a particular strategy for inlining string and memory operations.
Enable or disable warnings about deprecated @samp{vector long ...} Altivec
type usage. This option is enabled by default.
-@item --param rs6000-vect-unroll-limit=
-The vectorizer checks with target information to determine whether it
-would be beneficial to unroll the main vectorized loop and by how much. This
-parameter sets the upper bound of how much the vectorizer unrolls the main
-loop. The default value is four.
-
@end table
@node RX Options
--- /dev/null
+@c Copyright (C) 1988-2026 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@node Parameters
+@chapter Parameters
+@cindex parameters
+@cindex command-line parameters
+
+In some places, GCC uses parameters that are settable from the command line
+instead of arbitrary hard-wired constants. Many of these parameters
+control the amount of optimization that is done. For example, GCC does not
+inline functions that contain more than a certain number of instructions.
+You can control these parameters with the @option{--param} command-line option:
+
+@opindex param
+@example
+--param @var{name}=@var{value}
+--param=@var{name}=@var{value}
+@end example
+
+The names of specific parameters, and the meaning of the values, are
+tied to the internals of the compiler, and are subject to change
+without notice in future releases. Not all parameters are documented.
+
+To get a list of parameters supported by GCC, use the
+@option{--help=params} option.
+
+The @var{value} is an integer. In order to get the minimal, maximal
+and default values of a parameter, use the @option{--help=param -Q}
+options.
+
+@menu
+* General Parameters:: Parameters recognized on all targets.
+* Target-Specific Parameters:: Parameters for specific targets.
+@end menu
+
+@node General Parameters
+@section General Parameters
+
+The following choices of @var{name} are recognized for all targets:
+
+@table @gcctabopt
+@paindex auto-profile-bbs
+@item auto-profile-bbs
+If non-zero and used together with @option{-fauto-profile}, the auto-profile
+will be used to determine basic block profile. If zero, then only function
+level profile will be read.
+
+@paindex auto-profile-reorder-only
+@item auto-profile-reorder-only
+Enable only function reordering with auto-profile.
+
+@paindex phiopt-factor-max-stmts-live
+@item phiopt-factor-max-stmts-live
+When factoring statements out of if/then/else, this is the max # of statements
+after the defining statement to be allow to extend the lifetime of a name
+
+@paindex predictable-branch-outcome
+@item predictable-branch-outcome
+When branch is predicted to be taken with probability lower than this threshold
+(in percent), then it is considered well predictable.
+
+@paindex max-rtl-if-conversion-insns
+@item max-rtl-if-conversion-insns
+RTL if-conversion tries to remove conditional branches around a block and
+replace them with conditionally executed instructions. This parameter
+gives the maximum number of instructions in a block which should be
+considered for if-conversion. The compiler will
+also use other heuristics to decide whether if-conversion is likely to be
+profitable.
+
+@paindex file-cache-files
+@item file-cache-files
+Max number of files in the file cache.
+The file cache is used to print source lines in diagnostics and do some
+source checks like @option{-Wmisleading-indentation}.
+
+@paindex file-cache-lines
+@item file-cache-lines
+Max number of lines to index into file cache. When 0 this is automatically sized.
+The file cache is used to print source lines in diagnostics and do some
+source checks like @option{-Wmisleading-indentation}.
+
+@paindex max-rtl-if-conversion-predictable-cost
+@item max-rtl-if-conversion-predictable-cost
+RTL if-conversion will try to remove conditional branches around a block
+and replace them with conditionally executed instructions. These parameters
+give the maximum permissible cost for the sequence that would be generated
+by if-conversion depending on whether the branch is statically determined
+to be predictable or not. The units for this parameter are the same as
+those for the GCC internal seq_cost metric. The compiler will try to
+provide a reasonable default for this parameter using the BRANCH_COST
+target macro.
+
+@paindex max-crossjump-edges
+@item max-crossjump-edges
+The maximum number of incoming edges to consider for cross-jumping.
+The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in
+the number of edges incoming to each block. Increasing values mean
+more aggressive optimization, making the compilation time increase with
+probably small improvement in executable size.
+
+@paindex min-crossjump-insns
+@item min-crossjump-insns
+The minimum number of instructions that must be matched at the end
+of two blocks before cross-jumping is performed on them. This
+value is ignored in the case where all instructions in the block being
+cross-jumped from are matched.
+
+@paindex max-grow-copy-bb-insns
+@item max-grow-copy-bb-insns
+The maximum code size expansion factor when copying basic blocks
+instead of jumping. The expansion is relative to a jump instruction.
+
+@paindex max-goto-duplication-insns
+@item max-goto-duplication-insns
+The maximum number of instructions to duplicate to a block that jumps
+to a computed goto. To avoid @math{O(N^2)} behavior in a number of
+passes, GCC factors computed gotos early in the compilation process,
+and unfactors them as late as possible. Only computed jumps at the
+end of a basic blocks with no more than max-goto-duplication-insns are
+unfactored.
+
+@paindex max-delay-slot-insn-search
+@item max-delay-slot-insn-search
+The maximum number of instructions to consider when looking for an
+instruction to fill a delay slot. If more than this arbitrary number of
+instructions are searched, the time savings from filling the delay slot
+are minimal, so stop searching. Increasing values mean more
+aggressive optimization, making the compilation time increase with probably
+small improvement in execution time.
+
+@paindex max-delay-slot-live-search
+@item max-delay-slot-live-search
+When trying to fill delay slots, the maximum number of instructions to
+consider when searching for a block with valid live register
+information. Increasing this arbitrarily chosen value means more
+aggressive optimization, increasing the compilation time. This parameter
+should be removed when the delay slot code is rewritten to maintain the
+control-flow graph.
+
+@paindex max-devirt-targets
+@item max-devirt-targets
+This limits number of function a virtual call may be speculatively
+devirtualized to using static analysis (without profile feedback).
+
+@paindex max-gcse-memory
+@item max-gcse-memory
+The approximate maximum amount of memory in @code{kB} that can be allocated in
+order to perform the global common subexpression elimination
+optimization. If more memory than specified is required, the
+optimization is not done.
+
+@paindex max-gcse-insertion-ratio
+@item max-gcse-insertion-ratio
+If the ratio of expression insertions to deletions is larger than this value
+for any expression, then RTL PRE inserts or removes the expression and thus
+leaves partially redundant computations in the instruction stream.
+
+@paindex max-pending-list-length
+@item max-pending-list-length
+The maximum number of pending dependencies scheduling allows
+before flushing the current state and starting over. Large functions
+with few branches or calls can create excessively large lists which
+needlessly consume memory and resources.
+
+@paindex max-modulo-backtrack-attempts
+@item max-modulo-backtrack-attempts
+The maximum number of backtrack attempts the scheduler should make
+when modulo scheduling a loop. Larger values can exponentially increase
+compilation time.
+
+@paindex max-inline-functions-called-once-loop-depth
+@item max-inline-functions-called-once-loop-depth
+Maximal loop depth of a call considered by inline heuristics that tries to
+inline all functions called once.
+
+@paindex max-inline-functions-called-once-insns
+@item max-inline-functions-called-once-insns
+Maximal estimated size of functions produced while inlining functions called
+once.
+
+@paindex max-inline-insns-single
+@item max-inline-insns-single
+Several parameters control the tree inliner used in GCC@. This number sets the
+maximum number of instructions (counted in GCC's internal representation) in a
+single function that the tree inliner considers for inlining. This only
+affects functions declared inline and methods implemented in a class
+declaration (C++).
+
+
+@paindex max-inline-insns-auto
+@item max-inline-insns-auto
+When you use @option{-finline-functions} (included in @option{-O3}),
+a lot of functions that would otherwise not be considered for inlining
+by the compiler are investigated. To those functions, a different
+(more restrictive) limit compared to functions declared inline can
+be applied (@option{--param max-inline-insns-auto}).
+
+@paindex max-inline-insns-small
+@item max-inline-insns-small
+This is the bound applied to calls that are considered relevant with
+@option{-finline-small-functions}.
+
+@paindex max-inline-insns-size
+@item max-inline-insns-size
+This is the bound applied to calls that are optimized for size. Small growth
+may be desirable to anticipate optimization opportunities exposed by inlining.
+
+@paindex uninlined-function-insns
+@item uninlined-function-insns
+Number of instructions accounted by inliner for function overhead such as
+function prologue and epilogue.
+
+@paindex uninlined-function-time
+@item uninlined-function-time
+Extra time accounted by inliner for function overhead such as time needed to
+execute function prologue and epilogue.
+
+@paindex inline-heuristics-hint-percent
+@item inline-heuristics-hint-percent
+The scale (in percents) applied to @option{inline-insns-single},
+@option{inline-insns-single-O2}, @option{inline-insns-auto}
+when inline heuristics hints that inlining is
+very profitable (will enable later optimizations).
+
+@paindex uninlined-thunk-insns
+@item uninlined-thunk-insns
+@paindex uninlined-thunk-time
+@item uninlined-thunk-time
+Same as @option{--param uninlined-function-insns} and
+@option{--param uninlined-function-time} but applied to function thunks.
+
+@paindex inline-min-speedup
+@item inline-min-speedup
+When estimated performance improvement of caller + callee runtime exceeds this
+threshold (in percent), the function can be inlined regardless of the limit on
+@option{--param max-inline-insns-single} and @option{--param
+max-inline-insns-auto}.
+
+@paindex large-function-insns
+@item large-function-insns
+The limit specifying really large functions. For functions larger than this
+limit after inlining, inlining is constrained by
+@option{--param large-function-growth}. This parameter is useful primarily
+to avoid extreme compilation time caused by non-linear algorithms used by the
+back end.
+
+@paindex large-function-growth
+@item large-function-growth
+Specifies maximal growth of large functions caused by inlining in percents.
+For example, parameter value 100 limits large function growth to 2.0 times
+the original size.
+
+@paindex large-unit-insns
+@item large-unit-insns
+The limit specifying large translation unit. Growth caused by inlining of
+units larger than this limit is limited by @option{--param inline-unit-growth}.
+For small units this might be too tight.
+For example, consider a unit consisting of function A
+that is inline and B that just calls A three times. If B is small relative to
+A, the growth of unit is 300\% and yet such inlining is very sane. For very
+large units consisting of small inlineable functions, however, the overall unit
+growth limit is needed to avoid exponential explosion of code size. Thus for
+smaller units, the size is increased to @option{--param large-unit-insns}
+before applying @option{--param inline-unit-growth}.
+
+@paindex lazy-modules
+@item lazy-modules
+Maximum number of concurrently open C++ module files when lazy loading.
+
+@paindex inline-unit-growth
+@item inline-unit-growth
+Specifies maximal overall growth of the compilation unit caused by inlining.
+For example, parameter value 20 limits unit growth to 1.2 times the original
+size. Cold functions (either marked cold via an attribute or by profile
+feedback) are not accounted into the unit size.
+
+@paindex ipa-cp-unit-growth
+@item ipa-cp-unit-growth
+Specifies maximal overall growth of the compilation unit caused by
+interprocedural constant propagation. For example, parameter value 10 limits
+unit growth to 1.1 times the original size.
+
+@paindex ipa-cp-large-unit-insns
+@item ipa-cp-large-unit-insns
+The size of translation unit that IPA-CP pass considers large.
+
+@paindex large-stack-frame
+@item large-stack-frame
+The limit specifying large stack frames. While inlining the algorithm is trying
+to not grow past this limit too much.
+
+@paindex large-stack-frame-growth
+@item large-stack-frame-growth
+Specifies maximal growth of large stack frames caused by inlining in percents.
+For example, parameter value 1000 limits large stack frame growth to 11 times
+the original size.
+
+@paindex max-inline-insns-recursive
+@paindex max-inline-insns-recursive-auto
+@item max-inline-insns-recursive
+@itemx max-inline-insns-recursive-auto
+Specifies the maximum number of instructions an out-of-line copy of a
+self-recursive inline
+function can grow into by performing recursive inlining.
+
+@option{--param max-inline-insns-recursive} applies to functions
+declared inline.
+For functions not declared inline, recursive inlining
+happens only when @option{-finline-functions} (included in @option{-O3}) is
+enabled; @option{--param max-inline-insns-recursive-auto} applies instead.
+
+@paindex max-inline-recursive-depth
+@paindex max-inline-recursive-depth-auto
+@item max-inline-recursive-depth
+@itemx max-inline-recursive-depth-auto
+Specifies the maximum recursion depth used for recursive inlining.
+
+@option{--param max-inline-recursive-depth} applies to functions
+declared inline. For functions not declared inline, recursive inlining
+happens only when @option{-finline-functions} (included in @option{-O3}) is
+enabled; @option{--param max-inline-recursive-depth-auto} applies instead.
+
+@paindex min-inline-recursive-probability
+@item min-inline-recursive-probability
+Recursive inlining is profitable only for function having deep recursion
+in average and can hurt for function having little recursion depth by
+increasing the prologue size or complexity of function body to other
+optimizers.
+
+When profile feedback is available (see @option{-fprofile-generate}) the actual
+recursion depth can be guessed from the probability that function recurses
+via a given call expression. This parameter limits inlining only to call
+expressions whose probability exceeds the given threshold (in percents).
+
+@paindex early-inlining-insns
+@item early-inlining-insns
+Specify growth that the early inliner can make. In effect it increases
+the amount of inlining for code having a large abstraction penalty.
+
+@paindex max-early-inliner-iterations
+@item max-early-inliner-iterations
+Limit of iterations of the early inliner. This basically bounds
+the number of nested indirect calls the early inliner can resolve.
+Deeper chains are still handled by late inlining.
+
+@paindex comdat-sharing-probability
+@item comdat-sharing-probability
+Probability (in percent) that C++ inline function with comdat visibility
+are shared across multiple compilation units.
+
+@paindex modref-max-bases
+@item modref-max-bases
+@paindex modref-max-refs
+@item modref-max-refs
+@paindex modref-max-accesses
+@item modref-max-accesses
+Specifies the maximal number of base pointers, references and accesses stored
+for a single function by mod/ref analysis.
+
+@paindex modref-max-tests
+@item modref-max-tests
+Specifies the maxmal number of tests alias oracle can perform to disambiguate
+memory locations using the mod/ref information. This parameter ought to be
+bigger than @option{--param modref-max-bases} and @option{--param
+modref-max-refs}.
+
+@paindex modref-max-depth
+@item modref-max-depth
+Specifies the maximum depth of DFS walk used by modref escape analysis.
+Setting to 0 disables the analysis completely.
+
+@paindex modref-max-escape-points
+@item modref-max-escape-points
+Specifies the maximum number of escape points tracked by modref per SSA-name.
+
+@paindex modref-max-adjustments
+@item modref-max-adjustments
+Specifies the maximum number the access range is enlarged during modref dataflow
+analysis.
+
+@paindex profile-func-internal-id
+@item profile-func-internal-id
+A parameter to control whether to use function internal id in profile
+database lookup. If the value is 0, the compiler uses an id that
+is based on function assembler name and filename, which makes old profile
+data more tolerant to source changes such as function reordering etc.
+
+@paindex min-vect-loop-bound
+@item min-vect-loop-bound
+The minimum number of iterations under which loops are not vectorized
+when @option{-ftree-vectorize} is used. The number of iterations after
+vectorization needs to be greater than the value specified by this option
+to allow vectorization.
+
+@paindex gcse-cost-distance-ratio
+@item gcse-cost-distance-ratio
+Scaling factor in calculation of maximum distance an expression
+can be moved by GCSE optimizations. This is currently supported only in the
+code hoisting pass. The bigger the ratio, the more aggressive code hoisting
+is with simple expressions, i.e., the expressions that have cost
+less than @option{gcse-unrestricted-cost}. Specifying 0 disables
+hoisting of simple expressions.
+
+@paindex gcse-unrestricted-cost
+@item gcse-unrestricted-cost
+Cost, roughly measured as the cost of a single typical machine
+instruction, at which GCSE optimizations do not constrain
+the distance an expression can travel. This is currently
+supported only in the code hoisting pass. The lesser the cost,
+the more aggressive code hoisting is. Specifying 0
+allows all expressions to travel unrestricted distances.
+
+@paindex max-hoist-depth
+@item max-hoist-depth
+The depth of search in the dominator tree for expressions to hoist.
+This is used to avoid quadratic behavior in hoisting algorithm.
+The value of 0 does not limit on the search, but may slow down compilation
+of huge functions.
+
+@paindex max-tail-merge-comparisons
+@item max-tail-merge-comparisons
+The maximum amount of similar bbs to compare a bb with. This is used to
+avoid quadratic behavior in tree tail merging.
+
+@paindex max-tail-merge-iterations
+@item max-tail-merge-iterations
+The maximum amount of iterations of the pass over the function. This is used to
+limit compilation time in tree tail merging.
+
+@paindex store-merging-allow-unaligned
+@item store-merging-allow-unaligned
+Allow the store merging pass to introduce unaligned stores if it is legal to
+do so.
+
+@paindex max-stores-to-merge
+@item max-stores-to-merge
+The maximum number of stores to attempt to merge into wider stores in the store
+merging pass.
+
+@paindex max-store-chains-to-track
+@item max-store-chains-to-track
+The maximum number of store chains to track at the same time in the attempt
+to merge them into wider stores in the store merging pass.
+
+@paindex max-stores-to-track
+@item max-stores-to-track
+The maximum number of stores to track at the same time in the attemt to
+to merge them into wider stores in the store merging pass.
+
+@paindex max-unrolled-insns
+@item max-unrolled-insns
+The maximum number of instructions that a loop may have to be unrolled.
+If a loop is unrolled, this parameter also determines how many times
+the loop code is unrolled.
+
+@paindex max-average-unrolled-insns
+@item max-average-unrolled-insns
+The maximum number of instructions biased by probabilities of their execution
+that a loop may have to be unrolled. If a loop is unrolled,
+this parameter also determines how many times the loop code is unrolled.
+
+@paindex max-unroll-times
+@item max-unroll-times
+The maximum number of unrollings of a single loop.
+
+@paindex max-peeled-insns
+@item max-peeled-insns
+The maximum number of instructions that a loop may have to be peeled.
+If a loop is peeled, this parameter also determines how many times
+the loop code is peeled.
+
+@paindex max-peel-times
+@item max-peel-times
+The maximum number of peelings of a single loop.
+
+@paindex max-peel-branches
+@item max-peel-branches
+The maximum number of branches on the hot path through the peeled sequence.
+
+@paindex max-completely-peeled-insns
+@item max-completely-peeled-insns
+The maximum number of insns of a completely peeled loop.
+
+@paindex max-completely-peel-times
+@item max-completely-peel-times
+The maximum number of iterations of a loop to be suitable for complete peeling.
+
+@paindex max-completely-peel-loop-nest-depth
+@item max-completely-peel-loop-nest-depth
+The maximum depth of a loop nest suitable for complete peeling.
+
+@paindex max-unswitch-insns
+@item max-unswitch-insns
+The maximum number of insns of an unswitched loop.
+
+@paindex max-unswitch-depth
+@item max-unswitch-depth
+The maximum depth of a loop nest to be unswitched.
+
+@paindex lim-expensive
+@item lim-expensive
+The minimum cost of an expensive expression in the loop invariant motion.
+
+@paindex min-loop-cond-split-prob
+@item min-loop-cond-split-prob
+When FDO profile information is available, @option{min-loop-cond-split-prob}
+specifies minimum threshold for probability of semi-invariant condition
+statement to trigger loop split.
+
+@paindex iv-consider-all-candidates-bound
+@item iv-consider-all-candidates-bound
+Bound on number of candidates for induction variables, below which
+all candidates are considered for each use in induction variable
+optimizations. If there are more candidates than this,
+only the most relevant ones are considered to avoid quadratic time complexity.
+
+@paindex iv-max-considered-uses
+@item iv-max-considered-uses
+The induction variable optimizations give up on loops that contain more
+induction variable uses.
+
+@paindex iv-always-prune-cand-set-bound
+@item iv-always-prune-cand-set-bound
+If the number of candidates in the set is smaller than this value,
+always try to remove unnecessary ivs from the set
+when adding a new one.
+
+@paindex avg-loop-niter
+@item avg-loop-niter
+Average number of iterations of a loop.
+
+@paindex dse-max-object-size
+@item dse-max-object-size
+Maximum size (in bytes) of objects tracked bytewise by dead store elimination.
+Larger values may result in larger compilation times.
+
+@paindex dse-max-alias-queries-per-store
+@item dse-max-alias-queries-per-store
+Maximum number of queries into the alias oracle per store.
+Larger values result in larger compilation times and may result in more
+removed dead stores.
+
+@paindex scev-max-expr-size
+@item scev-max-expr-size
+Bound on size of expressions used in the scalar evolutions analyzer.
+Large expressions slow the analyzer.
+
+@paindex scev-max-expr-complexity
+@item scev-max-expr-complexity
+Bound on the complexity of the expressions in the scalar evolutions analyzer.
+Complex expressions slow the analyzer.
+
+@paindex max-tree-if-conversion-phi-args
+@item max-tree-if-conversion-phi-args
+Maximum number of arguments in a PHI supported by TREE if conversion
+unless the loop is marked with simd pragma.
+
+@paindex vect-max-layout-candidates
+@item vect-max-layout-candidates
+The maximum number of possible vector layouts (such as permutations)
+to consider when optimizing to-be-vectorized code.
+
+@paindex vect-max-version-for-alignment-checks
+@item vect-max-version-for-alignment-checks
+The maximum number of run-time checks that can be performed when
+doing loop versioning for alignment in the vectorizer.
+
+@paindex vect-max-version-for-alias-checks
+@item vect-max-version-for-alias-checks
+The maximum number of run-time checks that can be performed when
+doing loop versioning for alias in the vectorizer.
+
+@paindex vect-max-peeling-for-alignment
+@item vect-max-peeling-for-alignment
+The maximum number of loop peels to enhance access alignment
+for vectorizer. Value -1 means no limit.
+
+@paindex max-iterations-to-track
+@item max-iterations-to-track
+The maximum number of iterations of a loop the brute-force algorithm
+for analysis of the number of iterations of the loop tries to evaluate.
+
+@paindex hot-bb-count-fraction
+@item hot-bb-count-fraction
+The denominator n of fraction 1/n of the maximal execution count of a
+basic block in the entire program that a basic block needs to at least
+have in order to be considered hot. The default is 10000, which means
+that a basic block is considered hot if its execution count is greater
+than 1/10000 of the maximal execution count. 0 means that it is never
+considered hot. Used in non-LTO mode.
+
+@paindex hot-bb-count-ws-permille
+@item hot-bb-count-ws-permille
+The number of most executed permilles, ranging from 0 to 1000, of the
+profiled execution of the entire program to which the execution count
+of a basic block must be part of in order to be considered hot. The
+default is 990, which means that a basic block is considered hot if
+its execution count contributes to the upper 990 permilles, or 99.0%,
+of the profiled execution of the entire program. 0 means that it is
+never considered hot. Used in LTO mode.
+
+@paindex hot-bb-frequency-fraction
+@item hot-bb-frequency-fraction
+The denominator n of fraction 1/n of the execution frequency of the
+entry block of a function that a basic block of this function needs
+to at least have in order to be considered hot. The default is 1000,
+which means that a basic block is considered hot in a function if it
+is executed more frequently than 1/1000 of the frequency of the entry
+block of the function. 0 means that it is never considered hot.
+
+@paindex unlikely-bb-count-fraction
+@item unlikely-bb-count-fraction
+The denominator n of fraction 1/n of the number of profiled runs of
+the entire program below which the execution count of a basic block
+must be in order for the basic block to be considered unlikely executed.
+The default is 20, which means that a basic block is considered unlikely
+executed if it is executed in fewer than 1/20, or 5%, of the runs of
+the program. 0 means that it is always considered unlikely executed.
+
+@paindex max-predicted-iterations
+@item max-predicted-iterations
+The maximum number of loop iterations we predict statically. This is useful
+in cases where a function contains a single loop with known bound and
+another loop with unknown bound.
+The known number of iterations is predicted correctly, while
+the unknown number of iterations average to roughly 10. This means that the
+loop without bounds appears artificially cold relative to the other one.
+
+@paindex builtin-expect-probability
+@item builtin-expect-probability
+Control the probability of the expression having the specified value. This
+parameter takes a percentage (i.e.@: 0 ... 100) as input.
+
+@paindex builtin-string-cmp-inline-length
+@item builtin-string-cmp-inline-length
+The maximum length of a constant string for a builtin string cmp call
+eligible for inlining.
+
+@paindex align-threshold
+@item align-threshold
+
+Select fraction of the maximal frequency of executions of a basic block in
+a function to align the basic block.
+
+@paindex align-loop-iterations
+@item align-loop-iterations
+
+A loop expected to iterate at least the selected number of iterations is
+aligned.
+
+@paindex tracer-dynamic-coverage
+@paindex tracer-dynamic-coverage-feedback
+@item tracer-dynamic-coverage
+@itemx tracer-dynamic-coverage-feedback
+
+This value is used to limit superblock formation once the given percentage of
+executed instructions is covered. This limits unnecessary code size
+expansion.
+
+The @option{tracer-dynamic-coverage-feedback} parameter
+is used only when profile
+feedback is available. The real profiles (as opposed to statically estimated
+ones) are much less balanced allowing the threshold to be larger value.
+
+@paindex tracer-max-code-growth
+@item tracer-max-code-growth
+Stop tail duplication once code growth has reached given percentage. This is
+a rather artificial limit, as most of the duplicates are eliminated later in
+cross jumping, so it may be set to much higher values than is the desired code
+growth.
+
+@paindex tracer-min-branch-ratio
+@item tracer-min-branch-ratio
+
+Stop reverse growth when the reverse probability of best edge is less than this
+threshold (in percent).
+
+@paindex tracer-min-branch-probability
+@paindex tracer-min-branch-probability-feedback
+@item tracer-min-branch-probability
+@itemx tracer-min-branch-probability-feedback
+
+Stop forward growth if the best edge has probability lower than this
+threshold.
+
+Similarly to @option{tracer-dynamic-coverage} two parameters are
+provided. @option{tracer-min-branch-probability-feedback} is used for
+compilation with profile feedback and @option{tracer-min-branch-probability}
+compilation without. The value for compilation with profile feedback
+needs to be more conservative (higher) in order to make tracer
+effective.
+
+@paindex stack-clash-protection-guard-size
+@item stack-clash-protection-guard-size
+Specify the size of the operating system provided stack guard as
+2 raised to @var{num} bytes. Higher values may reduce the
+number of explicit probes, but a value larger than the operating system
+provided guard will leave code vulnerable to stack clash style attacks.
+
+@paindex stack-clash-protection-probe-interval
+@item stack-clash-protection-probe-interval
+Stack clash protection involves probing stack space as it is allocated. This
+param controls the maximum distance between probes into the stack as 2 raised
+to @var{num} bytes. Higher values may reduce the number of explicit probes, but a value
+larger than the operating system provided guard will leave code vulnerable to
+stack clash style attacks.
+
+@paindex max-cse-path-length
+@item max-cse-path-length
+
+The maximum number of basic blocks on path that CSE considers.
+
+@paindex max-cse-insns
+@item max-cse-insns
+The maximum number of instructions CSE processes before flushing.
+
+@paindex ggc-min-expand
+@item ggc-min-expand
+
+GCC uses a garbage collector to manage its own memory allocation. This
+parameter specifies the minimum percentage by which the garbage
+collector's heap should be allowed to expand between collections.
+Tuning this may improve compilation speed; it has no effect on code
+generation.
+
+The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when
+RAM >= 1GB@. If @code{getrlimit} is available, the notion of ``RAM'' is
+the smallest of actual RAM and @code{RLIMIT_DATA} or @code{RLIMIT_AS}. If
+GCC is not able to calculate RAM on a particular platform, the lower
+bound of 30% is used. Setting this parameter and
+@option{ggc-min-heapsize} to zero causes a full collection to occur at
+every opportunity. This is extremely slow, but can be useful for
+debugging.
+
+@paindex ggc-min-heapsize
+@item ggc-min-heapsize
+
+Minimum size of the garbage collector's heap before it begins bothering
+to collect garbage. The first collection occurs after the heap expands
+by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}. Again,
+tuning this may improve compilation speed, and has no effect on code
+generation.
+
+The default is the smaller of RAM/8, RLIMIT_RSS, or a limit that
+tries to ensure that RLIMIT_DATA or RLIMIT_AS are not exceeded, but
+with a lower bound of 4096 (four megabytes) and an upper bound of
+131072 (128 megabytes). If GCC is not able to calculate RAM on a
+particular platform, the lower bound is used. Setting this parameter
+very large effectively disables garbage collection. Setting this
+parameter and @option{ggc-min-expand} to zero causes a full collection
+to occur at every opportunity.
+
+@paindex max-reload-search-insns
+@item max-reload-search-insns
+The maximum number of instruction reload should look backward for equivalent
+register. Increasing values mean more aggressive optimization, making the
+compilation time increase with probably slightly better performance.
+
+@paindex max-cselib-memory-locations
+@item max-cselib-memory-locations
+The maximum number of memory locations cselib should take into account.
+Increasing values mean more aggressive optimization, making the compilation time
+increase with probably slightly better performance.
+
+@paindex max-sched-ready-insns
+@item max-sched-ready-insns
+The maximum number of instructions ready to be issued the scheduler should
+consider at any given time during the first scheduling pass. Increasing
+values mean more thorough searches, making the compilation time increase
+with probably little benefit.
+
+@paindex max-sched-region-blocks
+@item max-sched-region-blocks
+The maximum number of blocks in a region to be considered for
+interblock scheduling.
+
+@paindex max-pipeline-region-blocks
+@item max-pipeline-region-blocks
+The maximum number of blocks in a region to be considered for
+pipelining in the selective scheduler.
+
+@paindex max-sched-region-insns
+@item max-sched-region-insns
+The maximum number of insns in a region to be considered for
+interblock scheduling.
+
+@paindex max-pipeline-region-insns
+@item max-pipeline-region-insns
+The maximum number of insns in a region to be considered for
+pipelining in the selective scheduler.
+
+@paindex min-spec-prob
+@item min-spec-prob
+The minimum probability (in percents) of reaching a source block
+for interblock speculative scheduling.
+
+@paindex max-sched-extend-regions-iters
+@item max-sched-extend-regions-iters
+The maximum number of iterations through CFG to extend regions.
+A value of 0 disables region extensions.
+
+@paindex max-sched-insn-conflict-delay
+@item max-sched-insn-conflict-delay
+The maximum conflict delay for an insn to be considered for speculative motion.
+
+@paindex sched-spec-prob-cutoff
+@item sched-spec-prob-cutoff
+The minimal probability of speculation success (in percents), so that
+speculative insns are scheduled.
+
+@paindex sched-state-edge-prob-cutoff
+@item sched-state-edge-prob-cutoff
+The minimum probability an edge must have for the scheduler to save its
+state across it.
+
+@paindex sched-mem-true-dep-cost
+@item sched-mem-true-dep-cost
+Minimal distance (in CPU cycles) between store and load targeting same
+memory locations.
+
+@paindex selsched-max-lookahead
+@item selsched-max-lookahead
+The maximum size of the lookahead window of selective scheduling. It is a
+depth of search for available instructions.
+
+@paindex selsched-max-sched-times
+@item selsched-max-sched-times
+The maximum number of times that an instruction is scheduled during
+selective scheduling. This is the limit on the number of iterations
+through which the instruction may be pipelined.
+
+@paindex selsched-insns-to-rename
+@item selsched-insns-to-rename
+The maximum number of best instructions in the ready list that are considered
+for renaming in the selective scheduler.
+
+@paindex sms-min-sc
+@item sms-min-sc
+The minimum value of stage count that swing modulo scheduler
+generates.
+
+@paindex max-last-value-rtl
+@item max-last-value-rtl
+The maximum size measured as number of RTLs that can be recorded in an expression
+in combiner for a pseudo register as last known value of that register.
+
+@paindex max-combine-insns
+@item max-combine-insns
+The maximum number of instructions the RTL combiner tries to combine.
+
+@paindex max-combine-search-insns
+@item max-combine-search-insns
+The maximum number of instructions that the RTL combiner searches in order
+to find the next use of a given register definition. If this limit is reached
+without finding such a use, the combiner will stop trying to optimize the
+definition.
+
+Currently this limit only applies after certain successful combination
+attempts, but it could be extended to other cases in future.
+
+@paindex integer-share-limit
+@item integer-share-limit
+Small integer constants can use a shared data structure, reducing the
+compiler's memory usage and increasing its speed. This sets the maximum
+value of a shared integer constant.
+
+@paindex ssp-buffer-size
+@item ssp-buffer-size
+The minimum size of buffers (i.e.@: arrays) that receive stack smashing
+protection when @option{-fstack-protector} is used.
+
+@paindex min-size-for-stack-sharing
+@item min-size-for-stack-sharing
+The minimum size of variables taking part in stack slot sharing when not
+optimizing.
+
+@paindex max-jump-thread-duplication-stmts
+@item max-jump-thread-duplication-stmts
+Maximum number of statements allowed in a block that needs to be
+duplicated when threading jumps.
+
+@paindex max-jump-thread-paths
+@item max-jump-thread-paths
+The maximum number of paths to consider when searching for jump threading
+opportunities. When arriving at a block, incoming edges are only considered
+if the number of paths to be searched so far multiplied by the number of
+incoming edges does not exhaust the specified maximum number of paths to
+consider.
+
+@paindex max-fields-for-field-sensitive
+@item max-fields-for-field-sensitive
+Maximum number of fields in a structure treated in
+a field sensitive manner during pointer analysis.
+
+@paindex prefetch-latency
+@item prefetch-latency
+Estimate on average number of instructions that are executed before
+prefetch finishes. The distance prefetched ahead is proportional
+to this constant. Increasing this number may also lead to less
+streams being prefetched (see @option{simultaneous-prefetches}).
+
+@paindex simultaneous-prefetches
+@item simultaneous-prefetches
+Maximum number of prefetches that can run at the same time.
+
+@paindex l1-cache-line-size
+@item l1-cache-line-size
+The size of cache line in L1 data cache, in bytes.
+
+@paindex l1-cache-size
+@item l1-cache-size
+The size of L1 data cache, in kilobytes.
+
+@paindex l2-cache-size
+@item l2-cache-size
+The size of L2 data cache, in kilobytes.
+
+@paindex prefetch-dynamic-strides
+@item prefetch-dynamic-strides
+Whether the loop array prefetch pass should issue software prefetch hints
+for strides that are non-constant. In some cases this may be
+beneficial, though the fact the stride is non-constant may make it
+hard to predict when there is clear benefit to issuing these hints.
+
+Set to 1 if the prefetch hints should be issued for non-constant
+strides. Set to 0 if prefetch hints should be issued only for strides that
+are known to be constant and below @option{prefetch-minimum-stride}.
+
+@paindex prefetch-minimum-stride
+@item prefetch-minimum-stride
+Minimum constant stride, in bytes, to start using prefetch hints for. If
+the stride is less than this threshold, prefetch hints will not be issued.
+
+This setting is useful for processors that have hardware prefetchers, in
+which case there may be conflicts between the hardware prefetchers and
+the software prefetchers. If the hardware prefetchers have a maximum
+stride they can handle, it should be used here to improve the use of
+software prefetchers.
+
+A value of -1 means we don't have a threshold and therefore
+prefetch hints can be issued for any constant stride.
+
+This setting is only useful for strides that are known and constant.
+
+@paindex destructive-interference-size
+@item destructive-interference-size
+@paindex constructive-interference-size
+@item constructive-interference-size
+The values for the C++17 variables
+@code{std::hardware_destructive_interference_size} and
+@code{std::hardware_constructive_interference_size}. The destructive
+interference size is the minimum recommended offset between two
+independent concurrently-accessed objects; the constructive
+interference size is the maximum recommended size of contiguous memory
+accessed together. Typically both will be the size of an L1 cache
+line for the target, in bytes. For a generic target covering a range of L1
+cache line sizes, typically the constructive interference size will be
+the small end of the range and the destructive size will be the large
+end.
+
+The destructive interference size is intended to be used for layout,
+and thus has ABI impact. The default value is not expected to be
+stable, and on some targets varies with @option{-mtune}, so use of
+this variable in a context where ABI stability is important, such as
+the public interface of a library, is strongly discouraged; if it is
+used in that context, users can stabilize the value using this
+option.
+
+The constructive interference size is less sensitive, as it is
+typically only used in a @samp{static_assert} to make sure that a type
+fits within a cache line.
+
+See also @option{-Winterference-size}.
+
+@paindex loop-interchange-max-num-stmts
+@item loop-interchange-max-num-stmts
+The maximum number of stmts in a loop to be interchanged.
+
+@paindex loop-interchange-stride-ratio
+@item loop-interchange-stride-ratio
+The minimum ratio between stride of two loops for interchange to be profitable.
+
+@paindex min-insn-to-prefetch-ratio
+@item min-insn-to-prefetch-ratio
+The minimum ratio between the number of instructions and the
+number of prefetches to enable prefetching in a loop.
+
+@paindex prefetch-min-insn-to-mem-ratio
+@item prefetch-min-insn-to-mem-ratio
+The minimum ratio between the number of instructions and the
+number of memory references to enable prefetching in a loop.
+
+@paindex use-canonical-types
+@item use-canonical-types
+Whether the compiler should use the ``canonical'' type system.
+Should always be 1, which uses a more efficient internal
+mechanism for comparing types in C++ and Objective-C++. However, if
+bugs in the canonical type system are causing compilation failures,
+set this value to 0 to disable canonical types.
+
+@paindex switch-conversion-max-branch-ratio
+@item switch-conversion-max-branch-ratio
+Switch initialization conversion refuses to create arrays that are
+bigger than @option{switch-conversion-max-branch-ratio} times the number of
+branches in the switch.
+
+@paindex max-partial-antic-length
+@item max-partial-antic-length
+Maximum length of the partial antic set computed during the tree
+partial redundancy elimination optimization (@option{-ftree-pre}) when
+optimizing at @option{-O3} and above. For some sorts of source code
+the enhanced partial redundancy elimination optimization can run away,
+consuming all of the memory available on the host machine. This
+parameter sets a limit on the length of the sets that are computed,
+which prevents the runaway behavior. Setting a value of 0 for
+this parameter allows an unlimited set length.
+
+@paindex rpo-vn-max-loop-depth
+@item rpo-vn-max-loop-depth
+Maximum loop depth that is value-numbered optimistically.
+When the limit hits the innermost
+@var{rpo-vn-max-loop-depth} loops and the outermost loop in the
+loop nest are value-numbered optimistically and the remaining ones not.
+
+@paindex sccvn-max-alias-queries-per-access
+@item sccvn-max-alias-queries-per-access
+Maximum number of alias-oracle queries we perform when looking for
+redundancies for loads and stores. If this limit is hit the search
+is aborted and the load or store is not considered redundant. The
+number of queries is algorithmically limited to the number of
+stores on all paths from the load to the function entry.
+
+@paindex ira-max-loops-num
+@item ira-max-loops-num
+IRA uses regional register allocation by default. If a function
+contains more loops than the number given by this parameter, only at most
+the given number of the most frequently-executed loops form regions
+for regional register allocation.
+
+@paindex ira-max-conflict-table-size
+@item ira-max-conflict-table-size
+Although IRA uses a sophisticated algorithm to compress the conflict
+table, the table can still require excessive amounts of memory for
+huge functions. If the conflict table for a function could be more
+than the size in MB given by this parameter, the register allocator
+instead uses a faster, simpler, and lower-quality
+algorithm that does not require building a pseudo-register conflict table.
+
+@paindex ira-loop-reserved-regs
+@item ira-loop-reserved-regs
+IRA can be used to evaluate more accurate register pressure in loops
+for decisions to move loop invariants (see @option{-O3}). The number
+of available registers reserved for some other purposes is given
+by this parameter. Default of the parameter
+is the best found from numerous experiments.
+
+@paindex ira-consider-dup-in-all-alts
+@item ira-consider-dup-in-all-alts
+Make IRA to consider matching constraint (duplicated operand number)
+heavily in all available alternatives for preferred register class.
+If it is set as zero, it means IRA only respects the matching
+constraint when it's in the only available alternative with an
+appropriate register class. Otherwise, it means IRA will check all
+available alternatives for preferred register class even if it has
+found some choice with an appropriate register class and respect the
+found qualified matching constraint.
+
+@paindex ira-simple-lra-insn-threshold
+@item ira-simple-lra-insn-threshold
+Approximate function insn number in 1K units triggering simple local RA.
+
+@paindex lra-inheritance-ebb-probability-cutoff
+@item lra-inheritance-ebb-probability-cutoff
+LRA tries to reuse values reloaded in registers in subsequent insns.
+This optimization is called inheritance. EBB is used as a region to
+do this optimization. The parameter defines a minimal fall-through
+edge probability in percentage used to add BB to inheritance EBB in
+LRA. The default value was chosen
+from numerous runs of SPEC2000 on x86-64.
+
+@paindex loop-invariant-max-bbs-in-loop
+@item loop-invariant-max-bbs-in-loop
+Loop invariant motion can be very expensive, both in compilation time and
+in amount of needed compile-time memory, with very large loops. Loops
+with more basic blocks than this parameter won't have loop invariant
+motion optimization performed on them.
+
+@paindex loop-max-datarefs-for-datadeps
+@item loop-max-datarefs-for-datadeps
+Building data dependencies is expensive for very large loops. This
+parameter limits the number of data references in loops that are
+considered for data dependence analysis. These large loops are no
+handled by the optimizations using loop data dependencies.
+
+@paindex max-vartrack-size
+@item max-vartrack-size
+Sets a maximum number of hash table slots to use during variable
+tracking dataflow analysis of any function. If this limit is exceeded
+with variable tracking at assignments enabled, analysis for that
+function is retried without it, after removing all debug insns from
+the function. If the limit is exceeded even without debug insns, var
+tracking analysis is completely disabled for the function. Setting
+the parameter to zero makes it unlimited.
+
+@paindex max-vartrack-expr-depth
+@item max-vartrack-expr-depth
+Sets a maximum number of recursion levels when attempting to map
+variable names or debug temporaries to value expressions. This trades
+compilation time for more complete debug information. If this is set too
+low, value expressions that are available and could be represented in
+debug information may end up not being used; setting this higher may
+enable the compiler to find more complex debug expressions, but compile
+time and memory use may grow.
+
+@paindex max-debug-marker-count
+@item max-debug-marker-count
+Sets a threshold on the number of debug markers (e.g.@: begin stmt
+markers) to avoid complexity explosion at inlining or expanding to RTL.
+If a function has more such gimple stmts than the set limit, such stmts
+will be dropped from the inlined copy of a function, and from its RTL
+expansion.
+
+@paindex min-nondebug-insn-uid
+@item min-nondebug-insn-uid
+Use uids starting at this parameter for nondebug insns. The range below
+the parameter is reserved exclusively for debug insns created by
+@option{-fvar-tracking-assignments}, but debug insns may get
+(non-overlapping) uids above it if the reserved range is exhausted.
+
+@paindex ipa-sra-deref-prob-threshold
+@item ipa-sra-deref-prob-threshold
+IPA-SRA replaces a pointer which is known not be NULL with one or more
+new parameters only when the probability (in percent, relative to
+function entry) of it being dereferenced is higher than this parameter.
+
+@paindex ipa-sra-ptr-growth-factor
+@item ipa-sra-ptr-growth-factor
+IPA-SRA replaces a pointer to an aggregate with one or more new
+parameters only when their cumulative size is less or equal to
+@option{ipa-sra-ptr-growth-factor} times the size of the original
+pointer parameter.
+
+@paindex ipa-sra-ptrwrap-growth-factor
+@item ipa-sra-ptrwrap-growth-factor
+Additional maximum allowed growth of total size of new parameters
+that ipa-sra replaces a pointer to an aggregate with,
+if it points to a local variable that the caller only writes to and
+passes it as an argument to other functions.
+
+@paindex ipa-sra-max-replacements
+@item ipa-sra-max-replacements
+Maximum pieces of an aggregate that IPA-SRA tracks. As a
+consequence, it is also the maximum number of replacements of a formal
+parameter.
+
+@paindex sra-max-scalarization-size-Ospeed
+@paindex sra-max-scalarization-size-Osize
+@item sra-max-scalarization-size-Ospeed
+@itemx sra-max-scalarization-size-Osize
+The two Scalar Reduction of Aggregates passes (SRA and IPA-SRA) aim to
+replace scalar parts of aggregates with uses of independent scalar
+variables. These parameters control the maximum size, in storage units,
+of aggregate which is considered for replacement when compiling for
+speed
+(@option{sra-max-scalarization-size-Ospeed}) or size
+(@option{sra-max-scalarization-size-Osize}) respectively.
+
+@paindex sra-max-propagations
+@item sra-max-propagations
+The maximum number of artificial accesses that Scalar Replacement of
+Aggregates (SRA) will track, per one local variable, in order to
+facilitate copy propagation.
+
+@paindex tm-max-aggregate-size
+@item tm-max-aggregate-size
+When making copies of thread-local variables in a transaction, this
+parameter specifies the size in bytes after which variables are
+saved with the logging functions as opposed to save/restore code
+sequence pairs. This option only applies when using
+@option{-fgnu-tm}.
+
+@paindex graphite-max-nb-scop-params
+@item graphite-max-nb-scop-params
+To avoid exponential effects in the Graphite loop transforms, the
+number of parameters in a Static Control Part (SCoP) is bounded.
+A value of zero can be used to lift
+the bound. A variable whose value is unknown at compilation time and
+defined outside a SCoP is a parameter of the SCoP.
+
+@paindex hardcfr-max-blocks
+@item hardcfr-max-blocks
+Disable @option{-fharden-control-flow-redundancy} for functions with a
+larger number of blocks than the specified value. Zero removes any
+limit.
+
+@paindex hardcfr-max-inline-blocks
+@item hardcfr-max-inline-blocks
+Force @option{-fharden-control-flow-redundancy} to use out-of-line
+checking for functions with a larger number of basic blocks than the
+specified value.
+
+@paindex loop-block-tile-size
+@item loop-block-tile-size
+Loop blocking or strip mining transforms, enabled with
+@option{-floop-block} or @option{-floop-strip-mine}, strip mine each
+loop in the loop nest by a given number of iterations. The strip
+length can be changed using the @option{loop-block-tile-size}
+parameter.
+
+@paindex ipa-jump-function-lookups
+@item ipa-jump-function-lookups
+Specifies number of statements visited during jump function offset discovery.
+
+@paindex ipa-cp-value-list-size
+@item ipa-cp-value-list-size
+IPA-CP attempts to track all possible values and types passed to a function's
+parameter in order to propagate them and perform devirtualization.
+@option{ipa-cp-value-list-size} is the maximum number of values and types it
+stores per one formal parameter of a function.
+
+@paindex ipa-cp-eval-threshold
+@item ipa-cp-eval-threshold
+IPA-CP calculates its own score of cloning profitability heuristics
+and performs those cloning opportunities with scores that exceed
+@option{ipa-cp-eval-threshold}.
+
+@paindex ipa-cp-max-recursive-depth
+@item ipa-cp-max-recursive-depth
+Maximum depth of recursive cloning for self-recursive function.
+
+@paindex ipa-cp-min-recursive-probability
+@item ipa-cp-min-recursive-probability
+Recursive cloning only when the probability of call being executed exceeds
+the parameter.
+
+@paindex ipa-cp-recursive-freq-factor
+@item ipa-cp-recursive-freq-factor
+The number of times interprocedural copy propagation expects recursive
+functions to call themselves.
+
+@paindex ipa-cp-recursion-penalty
+@item ipa-cp-recursion-penalty
+Percentage penalty the recursive functions will receive when they
+are evaluated for cloning.
+
+@paindex ipa-cp-single-call-penalty
+@item ipa-cp-single-call-penalty
+Percentage penalty functions containing a single call to another
+function will receive when they are evaluated for cloning.
+
+@paindex ipa-cp-sweeps
+@item ipa-cp-sweeps
+The number of times the interprocedural constant propagation will traverse
+all functions to make cloning decisions.
+
+@paindex ipa-max-agg-items
+@item ipa-max-agg-items
+IPA-CP is also capable to propagate a number of scalar values passed
+in an aggregate. @option{ipa-max-agg-items} controls the maximum
+number of such values per one parameter.
+
+@paindex ipa-cp-loop-hint-bonus
+@item ipa-cp-loop-hint-bonus
+When IPA-CP determines that a cloning candidate would make the number
+of iterations of a loop known, it adds a bonus of
+@option{ipa-cp-loop-hint-bonus} to the profitability score of
+the candidate.
+
+@paindex ipa-max-loop-predicates
+@item ipa-max-loop-predicates
+The maximum number of different predicates IPA will use to describe when
+loops in a function have known properties.
+
+@paindex ipa-max-aa-steps
+@item ipa-max-aa-steps
+During its analysis of function bodies, IPA-CP employs alias analysis
+in order to track values pointed to by function parameters. In order
+not spend too much time analyzing huge functions, it gives up and
+consider all memory clobbered after examining
+@option{ipa-max-aa-steps} statements modifying memory.
+
+@paindex ipa-max-switch-predicate-bounds
+@item ipa-max-switch-predicate-bounds
+Maximal number of boundary endpoints of case ranges of switch statement.
+For switch exceeding this limit, IPA-CP will not construct cloning cost
+predicate, which is used to estimate cloning benefit, for default case
+of the switch statement.
+
+@paindex ipa-max-param-expr-ops
+@item ipa-max-param-expr-ops
+IPA-CP will analyze conditional statement that references some function
+parameter to estimate benefit for cloning upon certain constant value.
+But if number of operations in a parameter expression exceeds
+@option{ipa-max-param-expr-ops}, the expression is treated as complicated
+one, and is not handled by IPA analysis.
+
+@paindex lto-partitions
+@item lto-partitions
+Specify desired number of partitions produced during WHOPR compilation.
+The number of partitions should exceed the number of CPUs used for compilation.
+
+@paindex lto-min-partition
+@item lto-min-partition
+Size of minimal partition for WHOPR (in estimated instructions).
+This prevents expenses of splitting very small programs into too many
+partitions.
+
+@paindex lto-max-partition
+@item lto-max-partition
+Size of max partition for WHOPR (in estimated instructions).
+to provide an upper bound for individual size of partition.
+Meant to be used only with balanced partitioning.
+
+@paindex lto-partition-locality-frequency-cutoff
+@item lto-partition-locality-frequency-cutoff
+The denominator n of fraction 1/n of the execution frequency of callee to be
+cloned for a particular caller. Special value of 0 dictates to always clone
+without a cut-off.
+
+@paindex lto-partition-locality-size-cutoff
+@item lto-partition-locality-size-cutoff
+Size cut-off for callee including inlined calls to be cloned for a particular
+caller.
+
+@paindex lto-max-locality-partition
+@item lto-max-locality-partition
+Maximal size of a locality partition for LTO (in estimated instructions).
+Value of 0 results in default value being used.
+
+@paindex lto-max-streaming-parallelism
+@item lto-max-streaming-parallelism
+Maximal number of parallel processes used for LTO streaming.
+
+@paindex cxx-max-namespaces-for-diagnostic-help
+@item cxx-max-namespaces-for-diagnostic-help
+The maximum number of namespaces to consult for suggestions when C++
+name lookup fails for an identifier.
+
+@paindex sink-frequency-threshold
+@item sink-frequency-threshold
+The maximum relative execution frequency (in percents) of the target block
+relative to a statement's original block to allow statement sinking of a
+statement. Larger numbers result in more aggressive statement sinking.
+A small positive adjustment is applied for
+statements with memory operands as those are even more profitable so sink.
+
+@paindex max-stores-to-sink
+@item max-stores-to-sink
+The maximum number of conditional store pairs that can be sunk. Set to 0
+if either vectorization (@option{-ftree-vectorize}) or if-conversion
+(@option{-ftree-loop-if-convert}) is disabled.
+
+@paindex case-values-threshold
+@item case-values-threshold
+The smallest number of different values for which it is best to use a
+jump-table instead of a tree of conditional branches. If the value is
+0, use the default for the machine.
+
+@paindex jump-table-max-growth-ratio-for-size
+@item jump-table-max-growth-ratio-for-size
+The maximum code size growth ratio when expanding
+into a jump table (in percent). The parameter is used when
+optimizing for size.
+
+@paindex jump-table-max-growth-ratio-for-speed
+@item jump-table-max-growth-ratio-for-speed
+The maximum code size growth ratio when expanding
+into a jump table (in percent). The parameter is used when
+optimizing for speed.
+
+@paindex tree-reassoc-width
+@item tree-reassoc-width
+Set the maximum number of instructions executed in parallel in
+reassociated tree. This parameter overrides target dependent
+heuristics used by default if has non zero value.
+
+@paindex sched-pressure-algorithm
+@item sched-pressure-algorithm
+Choose between the two available implementations of
+@option{-fsched-pressure}. Algorithm 1 is the original implementation
+and is the more likely to prevent instructions from being reordered.
+Algorithm 2 was designed to be a compromise between the relatively
+conservative approach taken by algorithm 1 and the rather aggressive
+approach taken by the default scheduler. It relies more heavily on
+having a regular register file and accurate register pressure classes.
+See @file{haifa-sched.cc} in the GCC sources for more details.
+
+The default choice depends on the target.
+
+@paindex max-slsr-cand-scan
+@item max-slsr-cand-scan
+Set the maximum number of existing candidates that are considered when
+seeking a basis for a new straight-line strength reduction candidate.
+
+@paindex asan-globals
+@item asan-globals
+Enable buffer overflow detection for global objects. This kind
+of protection is enabled by default if you are using
+@option{-fsanitize=address} option.
+To disable global objects protection use @option{--param asan-globals=0}.
+
+@paindex asan-stack
+@item asan-stack
+Enable buffer overflow detection for stack objects. This kind of
+protection is enabled by default when using @option{-fsanitize=address}.
+To disable stack protection use @option{--param asan-stack=0} option.
+
+@paindex asan-instrument-reads
+@item asan-instrument-reads
+Enable buffer overflow detection for memory reads. This kind of
+protection is enabled by default when using @option{-fsanitize=address}.
+To disable memory reads protection use
+@option{--param asan-instrument-reads=0}.
+
+@paindex asan-instrument-writes
+@item asan-instrument-writes
+Enable buffer overflow detection for memory writes. This kind of
+protection is enabled by default when using @option{-fsanitize=address}.
+To disable memory writes protection use
+@option{--param asan-instrument-writes=0} option.
+
+@paindex asan-memintrin
+@item asan-memintrin
+Enable detection for built-in functions. This kind of protection
+is enabled by default when using @option{-fsanitize=address}.
+To disable built-in functions protection use
+@option{--param asan-memintrin=0}.
+
+@paindex asan-use-after-return
+@item asan-use-after-return
+Enable detection of use-after-return. This kind of protection
+is enabled by default when using the @option{-fsanitize=address} option.
+To disable it use @option{--param asan-use-after-return=0}.
+
+Note: By default the check is disabled at run time. To enable it,
+add @code{detect_stack_use_after_return=1} to the environment variable
+@env{ASAN_OPTIONS}.
+
+@paindex asan-instrumentation-with-call-threshold
+@item asan-instrumentation-with-call-threshold
+If number of memory accesses in function being instrumented
+is greater or equal to this number, use callbacks instead of inline checks.
+E.g. to disable inline code use
+@option{--param asan-instrumentation-with-call-threshold=0}.
+
+@paindex asan-kernel-mem-intrinsic-prefix
+@item asan-kernel-mem-intrinsic-prefix
+If nonzero, prefix calls to @code{memcpy}, @code{memset} and @code{memmove}
+with @samp{__asan_} or @samp{__hwasan_}
+for @option{-fsanitize=kernel-address} or @samp{-fsanitize=kernel-hwaddress},
+respectively.
+
+@paindex hwasan-instrument-stack
+@item hwasan-instrument-stack
+Enable hwasan instrumentation of statically sized stack-allocated variables.
+This kind of instrumentation is enabled by default when using
+@option{-fsanitize=hwaddress} and disabled by default when using
+@option{-fsanitize=kernel-hwaddress}.
+To disable stack instrumentation use
+@option{--param hwasan-instrument-stack=0}, and to enable it use
+@option{--param hwasan-instrument-stack=1}.
+
+@paindex hwasan-random-frame-tag
+@item hwasan-random-frame-tag
+When using stack instrumentation, decide tags for stack variables using a
+deterministic sequence beginning at a random tag for each frame. With this
+parameter unset tags are chosen using the same sequence but beginning from 1.
+This is enabled by default for @option{-fsanitize=hwaddress} and unavailable
+for @option{-fsanitize=kernel-hwaddress} and @option{-fsanitize=memtag-stack}.
+To disable it use @option{--param hwasan-random-frame-tag=0}.
+
+@paindex hwasan-instrument-allocas
+@item hwasan-instrument-allocas
+Enable hwasan instrumentation of dynamically sized stack-allocated variables.
+This kind of instrumentation is enabled by default when using
+@option{-fsanitize=hwaddress} and disabled by default when using
+@option{-fsanitize=kernel-hwaddress}.
+To disable instrumentation of such variables use
+@option{--param hwasan-instrument-allocas=0}, and to enable it use
+@option{--param hwasan-instrument-allocas=1}.
+
+@paindex hwasan-instrument-reads
+@item hwasan-instrument-reads
+Enable hwasan checks on memory reads. Instrumentation of reads is enabled by
+default for both @option{-fsanitize=hwaddress} and
+@option{-fsanitize=kernel-hwaddress}.
+To disable checking memory reads use
+@option{--param hwasan-instrument-reads=0}.
+
+@paindex hwasan-instrument-writes
+@item hwasan-instrument-writes
+Enable hwasan checks on memory writes. Instrumentation of writes is enabled by
+default for both @option{-fsanitize=hwaddress} and
+@option{-fsanitize=kernel-hwaddress}.
+To disable checking memory writes use
+@option{--param hwasan-instrument-writes=0}.
+
+@paindex hwasan-instrument-mem-intrinsics
+@item hwasan-instrument-mem-intrinsics
+Enable hwasan instrumentation of builtin functions. Instrumentation of these
+builtin functions is enabled by default for both @option{-fsanitize=hwaddress}
+and @option{-fsanitize=kernel-hwaddress}.
+To disable instrumentation of builtin functions use
+@option{--param hwasan-instrument-mem-intrinsics=0}.
+
+@paindex memtag-instrument-allocas
+@item memtag-instrument-allocas
+Enable hardware-assisted memory tagging of dynamically sized stack-allocated
+variables. This kind of code generation is enabled by default when using
+@option{-fsanitize=memtag-stack}.
+
+@paindex memtag-instrument-mem-intrinsics
+@item memtag-instrument-mem-intrinsics
+When sanitizing using MTE instructions, include builtin functions.
+
+@paindex use-after-scope-direct-emission-threshold
+@item use-after-scope-direct-emission-threshold
+If the size of a local variable in bytes is smaller or equal to this
+number, directly poison (or unpoison) shadow memory instead of using
+run-time callbacks.
+
+@paindex tsan-distinguish-volatile
+@item tsan-distinguish-volatile
+Emit special instrumentation for accesses to volatiles.
+
+@paindex tsan-instrument-func-entry-exit
+@item tsan-instrument-func-entry-exit
+Emit instrumentation calls to __tsan_func_entry() and __tsan_func_exit().
+
+@paindex max-fsm-thread-path-insns
+@item max-fsm-thread-path-insns
+Maximum number of instructions to copy when duplicating blocks on a
+finite state automaton jump thread path.
+
+@paindex threader-debug
+@item threader-debug
+threader-debug=[none|all] Enables verbose dumping of the threader solver.
+
+@paindex parloops-chunk-size
+@item parloops-chunk-size
+Chunk size of omp schedule for loops parallelized by parloops.
+
+@paindex parloops-schedule
+@item parloops-schedule
+Schedule type of omp schedule for loops parallelized by parloops (static,
+dynamic, guided, auto, runtime).
+
+@paindex parloops-min-per-thread
+@item parloops-min-per-thread
+The minimum number of iterations per thread of an innermost parallelized
+loop for which the parallelized variant is preferred over the single threaded
+one. Note that for a parallelized loop nest the
+minimum number of iterations of the outermost loop per thread is two.
+
+@paindex max-ssa-name-query-depth
+@item max-ssa-name-query-depth
+Maximum depth of recursion when querying properties of SSA names in things
+like fold routines. One level of recursion corresponds to following a
+use-def chain.
+
+@paindex max-speculative-devirt-maydefs
+@item max-speculative-devirt-maydefs
+The maximum number of may-defs we analyze when looking for a must-def
+specifying the dynamic type of an object that invokes a virtual call
+we may be able to devirtualize speculatively.
+
+@paindex ranger-debug
+@item ranger-debug
+Specifies the type of debug output to be issued for ranges.
+
+@paindex unroll-jam-min-percent
+@item unroll-jam-min-percent
+The minimum percentage of memory references that must be optimized
+away for the unroll-and-jam transformation to be considered profitable.
+
+@paindex unroll-jam-max-unroll
+@item unroll-jam-max-unroll
+The maximum number of times the outer loop should be unrolled by
+the unroll-and-jam transformation.
+
+@paindex max-rtl-if-conversion-unpredictable-cost
+@item max-rtl-if-conversion-unpredictable-cost
+Maximum permissible cost for the sequence that would be generated
+by the RTL if-conversion pass for a branch that is considered unpredictable.
+
+@paindex max-variable-expansions-in-unroller
+@item max-variable-expansions-in-unroller
+If @option{-fvariable-expansion-in-unroller} is used, the maximum number
+of times that an individual variable will be expanded during loop unrolling.
+
+@paindex partial-inlining-entry-probability
+@item partial-inlining-entry-probability
+Maximum probability of the entry BB of split region
+(in percent relative to entry BB of the function)
+to make partial inlining happen.
+
+@paindex max-tracked-strlens
+@item max-tracked-strlens
+Maximum number of strings for which strlen optimization pass will
+track string lengths.
+
+@paindex gcse-after-reload-partial-fraction
+@item gcse-after-reload-partial-fraction
+The threshold ratio for performing partial redundancy
+elimination after reload.
+
+@paindex gcse-after-reload-critical-fraction
+@item gcse-after-reload-critical-fraction
+The threshold ratio of critical edges execution count that
+permit performing redundancy elimination after reload.
+
+@paindex max-loop-header-insns
+@item max-loop-header-insns
+The maximum number of insns in loop header duplicated
+by the copy loop headers pass.
+
+@paindex vect-epilogues-nomask
+@item vect-epilogues-nomask
+Enable loop epilogue vectorization using smaller vector size.
+
+@paindex vect-partial-vector-usage
+@item vect-partial-vector-usage
+Controls when the loop vectorizer considers using partial vector loads
+and stores as an alternative to falling back to scalar code. 0 stops
+the vectorizer from ever using partial vector loads and stores. 1 allows
+partial vector loads and stores if vectorization removes the need for the
+code to iterate. 2 allows partial vector loads and stores in all loops.
+The parameter only has an effect on targets that support partial
+vector loads and stores.
+
+@paindex vect-inner-loop-cost-factor
+@item vect-inner-loop-cost-factor
+The maximum factor which the loop vectorizer applies to the cost of statements
+in an inner loop relative to the loop being vectorized. The factor applied
+is the maximum of the estimated number of iterations of the inner loop and
+this parameter. The default value of this parameter is 50.
+
+@paindex vect-induction-float
+@item vect-induction-float
+Enable loop vectorization of floating point inductions.
+
+@paindex vect-scalar-cost-multiplier
+@item vect-scalar-cost-multiplier
+Apply the given multiplier % to scalar loop costing during vectorization.
+Increasing the cost multiplier will make vector loops more profitable.
+
+@paindex vrp-block-limit
+@item vrp-block-limit
+Maximum number of basic blocks before VRP switches to a lower memory algorithm.
+
+@paindex vrp-cstload-limit
+@item vrp-cstload-limit
+Maximum number of steps when inferring a value range from a load from a constant aggregate.
+
+@paindex vrp-sparse-threshold
+@item vrp-sparse-threshold
+Maximum number of basic blocks before VRP uses a sparse bitmap cache.
+
+@paindex vrp-switch-limit
+@item vrp-switch-limit
+Maximum number of outgoing edges in a switch before VRP will not process it.
+
+@paindex vrp-vector-threshold
+@item vrp-vector-threshold
+Maximum number of basic blocks for VRP to use a basic cache vector.
+
+@paindex avoid-fma-max-bits
+@item avoid-fma-max-bits
+Maximum number of bits for which we avoid creating FMAs.
+
+@paindex fully-pipelined-fma
+@item fully-pipelined-fma
+Whether the target fully pipelines FMA instructions. If non-zero,
+reassociation considers the benefit of parallelizing FMA's multiplication
+part and addition part, assuming FMUL and FMA use the same units that can
+also do FADD.
+
+@paindex sms-loop-average-count-threshold
+@item sms-loop-average-count-threshold
+A threshold on the average loop count considered by the swing modulo scheduler.
+
+@paindex sms-dfa-history
+@item sms-dfa-history
+The number of cycles the swing modulo scheduler considers when checking
+conflicts using DFA.
+
+@paindex graphite-allow-codegen-errors
+@item graphite-allow-codegen-errors
+Whether codegen errors should be ICEs when @option{-fchecking}.
+
+@paindex sms-max-ii-factor
+@item sms-max-ii-factor
+A factor for tuning the upper bound that swing modulo scheduler
+uses for scheduling a loop.
+
+@paindex lra-max-considered-reload-pseudos
+@item lra-max-considered-reload-pseudos
+The max number of reload pseudos which are considered during
+spilling a non-reload pseudo.
+
+@paindex lra-max-pseudos-points-log2-considered-for-preferences
+@item lra-max-pseudos-points-log2-considered-for-preferences
+The maximum @code{log2(number of reload pseudos * number of
+program points)} threshold when preferences for other reload pseudos
+are still considered. Taking these preferences into account helps to
+improve register allocation. However, for very large functions, a
+large value can result in significant compilation time and memory
+consumption. The default value is 30.
+
+@paindex max-pow-sqrt-depth
+@item max-pow-sqrt-depth
+Maximum depth of sqrt chains to use when synthesizing exponentiation
+by a real constant.
+
+@paindex max-dse-active-local-stores
+@item max-dse-active-local-stores
+Maximum number of active local stores in RTL dead store elimination.
+
+@paindex asan-instrument-allocas
+@item asan-instrument-allocas
+Enable asan allocas/VLAs protection.
+
+@paindex max-iterations-computation-cost
+@item max-iterations-computation-cost
+Bound on the cost of an expression to compute the number of iterations.
+
+@paindex max-isl-operations
+@item max-isl-operations
+Maximum number of isl operations, 0 means unlimited.
+
+@paindex graphite-max-arrays-per-scop
+@item graphite-max-arrays-per-scop
+Maximum number of arrays per scop.
+
+@paindex max-vartrack-reverse-op-size
+@item max-vartrack-reverse-op-size
+Max. size of loc list for which reverse ops should be added.
+
+@paindex fsm-scale-path-stmts
+@item fsm-scale-path-stmts
+Scale factor to apply to the number of statements in a threading path
+crossing a loop backedge when comparing to
+@option{--param=max-jump-thread-duplication-stmts}.
+
+@paindex uninit-control-dep-attempts
+@item uninit-control-dep-attempts
+Maximum number of nested calls to search for control dependencies
+during uninitialized variable analysis.
+
+@paindex uninit-max-chain-len
+@item uninit-max-chain-len
+Maximum number of predicates anded for each predicate ored in the normalized
+predicate chain.
+
+@paindex uninit-max-num-chains
+@item uninit-max-num-chains
+Maximum number of predicates ored in the normalized predicate chain.
+
+@paindex uninit-max-prune-work
+@item uninit-max-prune-work
+Maximum amount of work done to prune paths where the variable is always initialized.
+
+@paindex sched-autopref-queue-depth
+@item sched-autopref-queue-depth
+Hardware autoprefetcher scheduler model control flag.
+Number of lookahead cycles the model looks into; at '
+' only enable instruction sorting heuristic.
+
+@paindex loop-versioning-max-inner-insns
+@item loop-versioning-max-inner-insns
+The maximum number of instructions that an inner loop can have
+before the loop versioning pass considers it too big to copy.
+
+@paindex loop-versioning-max-outer-insns
+@item loop-versioning-max-outer-insns
+The maximum number of instructions that an outer loop can have
+before the loop versioning pass considers it too big to copy,
+discounting any instructions in inner loops that directly benefit
+from versioning.
+
+@paindex ssa-name-def-chain-limit
+@item ssa-name-def-chain-limit
+The maximum number of SSA_NAME assignments to follow in determining
+a property of a variable such as its value. This limits the number
+of iterations or recursive calls GCC performs when optimizing certain
+statements or when determining their validity prior to issuing
+diagnostics.
+
+@paindex store-merging-max-size
+@item store-merging-max-size
+Maximum size of a single store merging region in bytes.
+
+@paindex store-forwarding-max-distance
+@item store-forwarding-max-distance
+Maximum number of instruction distance that a small store forwarded to a larger
+load may stall. Value '0' disables the cost checks for the
+avoid-store-forwarding pass.
+
+@paindex hash-table-verification-limit
+@item hash-table-verification-limit
+The number of elements for which hash table verification is done
+for each searched element.
+
+@paindex max-find-base-term-values
+@item max-find-base-term-values
+Maximum number of VALUEs handled during a single find_base_term call.
+
+@paindex analyzer-max-enodes-per-program-point
+@item analyzer-max-enodes-per-program-point
+The maximum number of exploded nodes per program point within
+the analyzer, before terminating analysis of that point.
+
+@paindex analyzer-max-constraints
+@item analyzer-max-constraints
+The maximum number of constraints per state.
+
+@paindex analyzer-min-snodes-for-call-summary
+@item analyzer-min-snodes-for-call-summary
+The minimum number of supernodes within a function for the
+analyzer to consider summarizing its effects at call sites.
+
+@paindex analyzer-max-enodes-for-full-dump
+@item analyzer-max-enodes-for-full-dump
+The maximum depth of exploded nodes that should appear in a dot dump
+before switching to a less verbose format.
+
+@paindex analyzer-max-recursion-depth
+@item analyzer-max-recursion-depth
+The maximum number of times a callsite can appear in a call stack
+within the analyzer, before terminating analysis of a call that would
+recurse deeper.
+
+@paindex analyzer-max-svalue-depth
+@item analyzer-max-svalue-depth
+The maximum depth of a symbolic value, before approximating
+the value as unknown.
+
+@paindex analyzer-max-infeasible-edges
+@item analyzer-max-infeasible-edges
+The maximum number of infeasible edges to reject before declaring
+a diagnostic as infeasible.
+
+@paindex gimple-fe-computed-hot-bb-threshold
+@item gimple-fe-computed-hot-bb-threshold
+The number of executions of a basic block which is considered hot.
+The parameter is used only in GIMPLE FE.
+
+@paindex analyzer-bb-explosion-factor
+@item analyzer-bb-explosion-factor
+The maximum number of 'after supernode' exploded nodes within the analyzer
+per supernode, before terminating analysis.
+
+@paindex analyzer-text-art-string-ellipsis-threshold
+@item analyzer-text-art-string-ellipsis-threshold
+The number of bytes at which to ellipsize string literals in analyzer text art diagrams.
+
+@paindex analyzer-text-art-ideal-canvas-width
+@item analyzer-text-art-ideal-canvas-width
+The ideal width in characters of text art diagrams generated by the analyzer.
+
+@paindex analyzer-text-art-string-ellipsis-head-len
+@item analyzer-text-art-string-ellipsis-head-len
+The number of literal bytes to show at the head of a string literal in text art when ellipsizing it.
+
+@paindex analyzer-text-art-string-ellipsis-tail-len
+@item analyzer-text-art-string-ellipsis-tail-len
+The number of literal bytes to show at the tail of a string literal in text art when ellipsizing it.
+
+@paindex ranger-logical-depth
+@item ranger-logical-depth
+Maximum depth of logical expression evaluation ranger will look through
+when evaluating outgoing edge ranges.
+
+@paindex ranger-recompute-depth
+@item ranger-recompute-depth
+Maximum depth of instruction chains to consider for recomputation
+in the outgoing range calculator.
+
+@paindex relation-block-limit
+@item relation-block-limit
+Maximum number of relations the oracle will register in a basic block.
+
+@paindex transitive-relations-work-bound
+@item transitive-relations-work-bound
+Work bound when discovering transitive relations from existing relations.
+
+@paindex min-pagesize
+@item min-pagesize
+Minimum page size for warning and early break vectorization purposes.
+
+@paindex openacc-kernels
+@item openacc-kernels
+Specify mode of OpenACC `kernels' constructs handling.
+With @option{--param=openacc-kernels=decompose}, OpenACC `kernels'
+constructs are decomposed into parts, a sequence of compute
+constructs, each then handled individually.
+This is work in progress.
+With @option{--param=openacc-kernels=parloops}, OpenACC `kernels'
+constructs are handled by the @samp{parloops} pass, en bloc.
+This is the current default.
+
+@paindex openacc-privatization
+@item openacc-privatization
+Control whether the @option{-fopt-info-omp-note} and applicable
+@option{-fdump-tree-*-details} options emit OpenACC privatization diagnostics.
+With @option{--param=openacc-privatization=quiet}, don't diagnose.
+This is the current default.
+With @option{--param=openacc-privatization=noisy}, do diagnose.
+
+@paindex cycle-accurate-model
+@item cycle-accurate-model
+Specifies whether GCC should assume that the scheduling description is mostly
+a cycle-accurate model of the target processor the code is intended to
+run on, in the absence of cache misses. Nonzero means that the selected
+scheduling model is accurate and likely describes an in-order processor,
+and that scheduling should aggressively spill to try and fill any pipeline
+bubbles. This is the current default. Zero means the scheduling description
+might not be available/accurate or perhaps not applicable at all, such as for
+modern out-of-order processors.
+
+@end table
+
+@node Target-Specific Parameters
+@section Target-Specific Parameters
+@cindex target-specific parameters
+
+Several back ends have their own parameters.
+
+@menu
+* AArch64 Parameters::
+* AMD GCN Parameters::
+* LoongArch Parameters::
+* RISC-V Parameters::
+* RS/6000 and PowerPC Parameters::
+* x86 Parameters::
+@end menu
+
+@node AArch64 Parameters
+@subsection AArch64 Parameters
+@cindex AArch64 parameters
+The following choices of @var{name} are available on AArch64 targets:
+
+@table @gcctabopt
+@paindex aarch64-vect-compare-costs
+@item aarch64-vect-compare-costs
+When vectorizing, consider using multiple different approaches and use
+the cost model to choose the cheapest one. This includes:
+
+@itemize
+@item
+Trying both SVE and Advanced SIMD, when SVE is available.
+
+@item
+Trying to use 64-bit Advanced SIMD vectors for the smallest data elements,
+rather than using 128-bit vectors for everything.
+
+@item
+Trying to use ``unpacked'' SVE vectors for smaller elements. This includes
+storing smaller elements in larger containers and accessing elements with
+extending loads and truncating stores.
+@end itemize
+
+@paindex aarch64-float-recp-precision
+@item aarch64-float-recp-precision
+The number of Newton iterations for calculating the reciprocal for float type.
+The precision of division is proportional to this param when division
+approximation is enabled. The default value is 1.
+
+@paindex aarch64-double-recp-precision
+@item aarch64-double-recp-precision
+The number of Newton iterations for calculating the reciprocal for double type.
+The precision of division is proportional to this param when division
+approximation is enabled. The default value is 2.
+
+@paindex aarch64-autovec-preference
+@item aarch64-autovec-preference
+An old alias for @option{-mautovec-preference}. If both
+@option{-mautovec-preference} and @option{--param=aarch64-autovec-preference}
+are passed, the @option{--param} value will be used.
+
+@paindex aarch64-ldp-policy
+@item aarch64-ldp-policy
+Fine-grained policy for load pairs.
+With @option{--param=aarch64-ldp-policy=default}, use the policy of the
+tuning structure. This is the current default.
+With @option{--param=aarch64-ldp-policy=always}, emit ldp regardless
+of alignment.
+With @option{--param=aarch64-ldp-policy=never}, do not emit ldp.
+With @option{--param=aarch64-ldp-policy=aligned}, emit ldp only if the
+source pointer is aligned to at least double the alignment of the type.
+
+@paindex aarch64-stp-policy
+@item aarch64-stp-policy
+Fine-grained policy for store pairs.
+With @option{--param=aarch64-stp-policy=default}, use the policy of the
+tuning structure. This is the current default.
+With @option{--param=aarch64-stp-policy=always}, emit stp regardless
+of alignment.
+With @option{--param=aarch64-stp-policy=never}, do not emit stp.
+With @option{--param=aarch64-stp-policy=aligned}, emit stp only if the
+source pointer is aligned to at least double the alignment of the type.
+
+@paindex aarch64-ldp-alias-check-limit
+@item aarch64-ldp-alias-check-limit
+Limit on the number of alias checks performed by the AArch64 load/store pair
+fusion pass when attempting to form an ldp/stp. Higher values make the pass
+more aggressive at re-ordering loads over stores, at the expense of increased
+compile time.
+
+@paindex aarch64-ldp-writeback
+@item aarch64-ldp-writeback
+Param to control which writeback opportunities we try to handle in the AArch64
+load/store pair fusion pass. A value of zero disables writeback handling. One
+means we try to form pairs involving one or more existing individual writeback
+accesses where possible. A value of two means we also try to opportunistically
+form writeback opportunities by folding in trailing destructive updates of the
+base register used by a pair.
+
+@paindex aarch64-loop-vect-issue-rate-niters
+@item aarch64-loop-vect-issue-rate-niters
+The tuning for some AArch64 CPUs tries to take both latencies and issue
+rates into account when deciding whether a loop should be vectorized
+using SVE, vectorized using Advanced SIMD, or not vectorized at all.
+If this parameter is set to @var{n}, GCC will not use this heuristic
+for loops that are known to execute in fewer than @var{n} Advanced
+SIMD iterations.
+
+@paindex aarch64-vect-unroll-limit
+@item aarch64-vect-unroll-limit
+The vectorizer will use available tuning information to determine whether it
+would be beneficial to unroll the main vectorized loop and by how much. This
+parameter set's the upper bound of how much the vectorizer will unroll the main
+loop. The default value is four.
+
+@paindex aarch64-tag-memory-loop-threshold
+@item aarch64-tag-memory-loop-threshold
+Param to control the treshold in number of granules beyond which an
+explicit loop for tagging a memory block is emitted. The memory block
+is tagged using MTE instructions.
+
+@end table
+
+@node AMD GCN Parameters
+@subsection AMD GCN Parameters
+@cindex AMD GCN parameters
+The following choices of @var{name} are available on GCN targets:
+
+@table @gcctabopt
+@paindex gcn-preferred-vectorization-factor
+@item gcn-preferred-vectorization-factor
+Preferred vectorization factor: @samp{default}, @samp{32}, @samp{64}.
+
+@end table
+
+@node LoongArch Parameters
+@subsection LoongArch Parameters
+@cindex LoongArch parameters
+The following parameters are available on LoongArch targets:
+
+@table @gcctabopt
+@paindex loongarch-vect-unroll-limit
+@item loongarch-vect-unroll-limit
+The vectorizer uses available tuning information to determine whether it
+would be beneficial to unroll the main vectorized loop and by how much. This
+parameter sets the upper bound of how much the vectorizer unrolls the main
+loop. The default value is six.
+
+@end table
+
+@node RISC-V Parameters
+@subsection RISC-V Parameters
+@cindex RISC-V parameters
+The following parameters are available on RISC-V targets:
+
+@table @gcctabopt
+@paindex riscv-strcmp-inline-limit
+@item riscv-strcmp-inline-limit
+The maximum number of bytes compared by the inlined code for @code{strcmp}
+and @code{strncmp} when enabled by the @option{-minline-strcmp} and
+@option{-minline-strncmp} options, respectively.
+The default value is 64.
+@end table
+
+@node RS/6000 and PowerPC Parameters
+@subsection RS/6000 and PowerPC Parameters
+@cindex RS/6000 and PowerPC parameters
+The following parameters are available on RS/6000 and PowerPC targets:
+
+@table @gcctabopt
+@paindex rs6000-vect-unroll-limit
+@item rs6000-vect-unroll-limit
+The vectorizer checks with target information to determine whether it
+would be beneficial to unroll the main vectorized loop and by how much. This
+parameter sets the upper bound of how much the vectorizer unrolls the main
+loop. The default value is four.
+@end table
+
+@node x86 Parameters
+@subsection x86 Parameters
+@cindex x86 parameters
+The following choices of @var{name} are available on i386 and x86_64 targets:
+
+@table @gcctabopt
+@paindex x86-stlf-window-ninsns
+@item x86-stlf-window-ninsns
+Instructions number above which STFL stall penalty can be compensated.
+
+@paindex x86-stv-max-visits
+@item x86-stv-max-visits
+The maximum number of use and def visits when discovering a STV chain before
+the discovery is aborted.
+
+@paindex ix86-vect-unroll-limit
+@item ix86-vect-unroll-limit
+Limit how much the autovectorizer may unroll a loop.
+
+@paindex ix86-vect-compare-costs
+@item ix86-vect-compare-costs
+Whether x86 vectorizer cost modeling compares costs of different vector sizes.
+
+@end table
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