/* Predicate aware uninitialized variable warning.
- Copyright (C) 2001-2013 Free Software Foundation, Inc.
+ Copyright (C) 2001-2021 Free Software Foundation, Inc.
Contributed by Xinliang David Li <davidxl@google.com>
This file is part of GCC.
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
+#define INCLUDE_STRING
#include "config.h"
#include "system.h"
#include "coretypes.h"
-#include "tm.h"
+#include "backend.h"
#include "tree.h"
-#include "flags.h"
-#include "tm_p.h"
-#include "basic-block.h"
-#include "function.h"
-#include "gimple-pretty-print.h"
-#include "bitmap.h"
-#include "pointer-set.h"
-#include "tree-ssa.h"
#include "gimple.h"
-#include "tree-inline.h"
-#include "hashtab.h"
#include "tree-pass.h"
+#include "ssa.h"
+#include "gimple-pretty-print.h"
#include "diagnostic-core.h"
+#include "fold-const.h"
+#include "gimple-iterator.h"
+#include "tree-ssa.h"
+#include "tree-cfg.h"
+#include "cfghooks.h"
+#include "attribs.h"
+#include "builtins.h"
+#include "calls.h"
+#include "gimple-range.h"
/* This implements the pass that does predicate aware warning on uses of
- possibly uninitialized variables. The pass first collects the set of
- possibly uninitialized SSA names. For each such name, it walks through
- all its immediate uses. For each immediate use, it rebuilds the condition
- expression (the predicate) that guards the use. The predicate is then
+ possibly uninitialized variables. The pass first collects the set of
+ possibly uninitialized SSA names. For each such name, it walks through
+ all its immediate uses. For each immediate use, it rebuilds the condition
+ expression (the predicate) that guards the use. The predicate is then
examined to see if the variable is always defined under that same condition.
This is done either by pruning the unrealizable paths that lead to the
default definitions or by checking if the predicate set that guards the
defining paths is a superset of the use predicate. */
+/* Max PHI args we can handle in pass. */
+const unsigned max_phi_args = 32;
/* Pointer set of potentially undefined ssa names, i.e.,
ssa names that are defined by phi with operands that
are not defined or potentially undefined. */
-static struct pointer_set_t *possibly_undefined_names = 0;
+static hash_set<tree> *possibly_undefined_names = 0;
/* Bit mask handling macros. */
#define MASK_SET_BIT(mask, pos) mask |= (1 << pos)
#define MASK_EMPTY(mask) (mask == 0)
/* Returns the first bit position (starting from LSB)
- in mask that is non zero. Returns -1 if the mask is empty. */
+ in mask that is non zero. Returns -1 if the mask is empty. */
static int
get_mask_first_set_bit (unsigned mask)
{
has_undefined_value_p (tree t)
{
return (ssa_undefined_value_p (t)
- || (possibly_undefined_names
- && pointer_set_contains (possibly_undefined_names, t)));
+ || (possibly_undefined_names
+ && possibly_undefined_names->contains (t)));
+}
+
+/* Return true if EXPR should suppress either uninitialized warning. */
+
+static inline bool
+get_no_uninit_warning (tree expr)
+{
+ return warning_suppressed_p (expr, OPT_Wuninitialized);
}
+/* Suppress both uninitialized warnings for EXPR. */
+static inline void
+set_no_uninit_warning (tree expr)
+{
+ suppress_warning (expr, OPT_Wuninitialized);
+}
-/* Like has_undefined_value_p, but don't return true if TREE_NO_WARNING
- is set on SSA_NAME_VAR. */
+/* Like has_undefined_value_p, but don't return true if the no-warning
+ bit is set on SSA_NAME_VAR for either uninit warning. */
static inline bool
-uninit_undefined_value_p (tree t) {
+uninit_undefined_value_p (tree t)
+{
if (!has_undefined_value_p (t))
return false;
- if (SSA_NAME_VAR (t) && TREE_NO_WARNING (SSA_NAME_VAR (t)))
- return false;
- return true;
+ if (!SSA_NAME_VAR (t))
+ return true;
+ return !get_no_uninit_warning (SSA_NAME_VAR (t));
}
/* Emit warnings for uninitialized variables. This is done in two passes.
/* Emit a warning for EXPR based on variable VAR at the point in the
program T, an SSA_NAME, is used being uninitialized. The exact
- warning text is in MSGID and LOCUS may contain a location or be null.
- WC is the warning code. */
+ warning text is in MSGID and DATA is the gimple stmt with info about
+ the location in source code. When DATA is a GIMPLE_PHI, PHIARG_IDX
+ gives which argument of the phi node to take the location from. WC
+ is the warning code. */
static void
-warn_uninit (enum opt_code wc, tree t,
- tree expr, tree var, const char *gmsgid, void *data)
+warn_uninit (enum opt_code wc, tree t, tree expr, tree var,
+ const char *gmsgid, void *data, location_t phiarg_loc)
{
- gimple context = (gimple) data;
+ gimple *context = (gimple *) data;
location_t location, cfun_loc;
expanded_location xloc, floc;
+ /* Ignore COMPLEX_EXPR as initializing only a part of a complex
+ turns in a COMPLEX_EXPR with the not initialized part being
+ set to its previous (undefined) value. */
+ if (is_gimple_assign (context)
+ && gimple_assign_rhs_code (context) == COMPLEX_EXPR)
+ return;
if (!has_undefined_value_p (t))
return;
+ /* Anonymous SSA_NAMEs shouldn't be uninitialized, but ssa_undefined_value_p
+ can return true if the def stmt of anonymous SSA_NAME is COMPLEX_EXPR
+ created for conversion from scalar to complex. Use the underlying var of
+ the COMPLEX_EXPRs real part in that case. See PR71581. */
+ if (expr == NULL_TREE
+ && var == NULL_TREE
+ && SSA_NAME_VAR (t) == NULL_TREE
+ && is_gimple_assign (SSA_NAME_DEF_STMT (t))
+ && gimple_assign_rhs_code (SSA_NAME_DEF_STMT (t)) == COMPLEX_EXPR)
+ {
+ tree v = gimple_assign_rhs1 (SSA_NAME_DEF_STMT (t));
+ if (TREE_CODE (v) == SSA_NAME
+ && has_undefined_value_p (v)
+ && zerop (gimple_assign_rhs2 (SSA_NAME_DEF_STMT (t))))
+ {
+ expr = SSA_NAME_VAR (v);
+ var = expr;
+ }
+ }
+
+ if (expr == NULL_TREE)
+ return;
+
/* TREE_NO_WARNING either means we already warned, or the front end
wishes to suppress the warning. */
if ((context
- && (gimple_no_warning_p (context)
+ && (warning_suppressed_p (context, OPT_Wuninitialized)
|| (gimple_assign_single_p (context)
- && TREE_NO_WARNING (gimple_assign_rhs1 (context)))))
- || TREE_NO_WARNING (expr))
+ && get_no_uninit_warning (gimple_assign_rhs1 (context)))))
+ || get_no_uninit_warning (expr))
return;
- location = (context != NULL && gimple_has_location (context))
- ? gimple_location (context)
- : DECL_SOURCE_LOCATION (var);
+ if (context != NULL && gimple_has_location (context))
+ location = gimple_location (context);
+ else if (phiarg_loc != UNKNOWN_LOCATION)
+ location = phiarg_loc;
+ else
+ location = DECL_SOURCE_LOCATION (var);
location = linemap_resolve_location (line_table, location,
- LRK_SPELLING_LOCATION,
- NULL);
+ LRK_SPELLING_LOCATION, NULL);
cfun_loc = DECL_SOURCE_LOCATION (cfun->decl);
xloc = expand_location (location);
floc = expand_location (cfun_loc);
+ auto_diagnostic_group d;
if (warning_at (location, wc, gmsgid, expr))
{
- TREE_NO_WARNING (expr) = 1;
+ suppress_warning (expr, wc);
if (location == DECL_SOURCE_LOCATION (var))
return;
if (xloc.file != floc.file
- || linemap_location_before_p (line_table,
- location, cfun_loc)
- || linemap_location_before_p (line_table,
- cfun->function_end_locus,
+ || linemap_location_before_p (line_table, location, cfun_loc)
+ || linemap_location_before_p (line_table, cfun->function_end_locus,
location))
inform (DECL_SOURCE_LOCATION (var), "%qD was declared here", var);
}
}
+struct check_defs_data
+{
+ /* If we found any may-defs besides must-def clobbers. */
+ bool found_may_defs;
+};
+
+/* Return true if STMT is a call to built-in function all of whose
+ by-reference arguments are const-qualified (i.e., the function can
+ be assumed not to modify them). */
+
+static bool
+builtin_call_nomodifying_p (gimple *stmt)
+{
+ if (!gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
+ return false;
+
+ tree fndecl = gimple_call_fndecl (stmt);
+ if (!fndecl)
+ return false;
+
+ tree fntype = TREE_TYPE (fndecl);
+ if (!fntype)
+ return false;
+
+ /* Check the called function's signature for non-constc pointers.
+ If one is found, return false. */
+ unsigned argno = 0;
+ tree argtype;
+ function_args_iterator it;
+ FOREACH_FUNCTION_ARGS (fntype, argtype, it)
+ {
+ if (VOID_TYPE_P (argtype))
+ return true;
+
+ ++argno;
+
+ if (!POINTER_TYPE_P (argtype))
+ continue;
+
+ if (TYPE_READONLY (TREE_TYPE (argtype)))
+ continue;
+
+ return false;
+ }
+
+ /* If the number of actual arguments to the call is less than or
+ equal to the number of parameters, return false. */
+ unsigned nargs = gimple_call_num_args (stmt);
+ if (nargs <= argno)
+ return false;
+
+ /* Check arguments passed through the ellipsis in calls to variadic
+ functions for pointers. If one is found that's a non-constant
+ pointer, return false. */
+ for (; argno < nargs; ++argno)
+ {
+ tree arg = gimple_call_arg (stmt, argno);
+ argtype = TREE_TYPE (arg);
+ if (!POINTER_TYPE_P (argtype))
+ continue;
+
+ if (TYPE_READONLY (TREE_TYPE (argtype)))
+ continue;
+
+ return false;
+ }
+
+ return true;
+}
+
+/* If ARG is a FNDECL parameter declared with attribute access none or
+ write_only issue a warning for its read access via PTR. */
+
+static void
+maybe_warn_read_write_only (tree fndecl, gimple *stmt, tree arg, tree ptr)
+{
+ if (!fndecl)
+ return;
+
+ if (get_no_uninit_warning (arg))
+ return;
+
+ tree fntype = TREE_TYPE (fndecl);
+ if (!fntype)
+ return;
+
+ /* Initialize a map of attribute access specifications for arguments
+ to the function function call. */
+ rdwr_map rdwr_idx;
+ init_attr_rdwr_indices (&rdwr_idx, TYPE_ATTRIBUTES (fntype));
+
+ unsigned argno = 0;
+ tree parms = DECL_ARGUMENTS (fndecl);
+ for (tree parm = parms; parm; parm = TREE_CHAIN (parm), ++argno)
+ {
+ if (parm != arg)
+ continue;
+
+ const attr_access* access = rdwr_idx.get (argno);
+ if (!access)
+ break;
+
+ if (access->mode != access_none
+ && access->mode != access_write_only)
+ continue;
+
+ location_t stmtloc
+ = linemap_resolve_location (line_table, gimple_location (stmt),
+ LRK_SPELLING_LOCATION, NULL);
+
+ if (!warning_at (stmtloc, OPT_Wmaybe_uninitialized,
+ "%qE may be used uninitialized", ptr))
+ break;
+
+ suppress_warning (arg, OPT_Wmaybe_uninitialized);
+
+ const char* const access_str =
+ TREE_STRING_POINTER (access->to_external_string ());
+
+ location_t parmloc = DECL_SOURCE_LOCATION (parm);
+ inform (parmloc, "accessing argument %u of a function declared with "
+ "attribute %<%s%>",
+ argno + 1, access_str);
+
+ break;
+ }
+}
+
+/* Callback for walk_aliased_vdefs. */
+
+static bool
+check_defs (ao_ref *ref, tree vdef, void *data_)
+{
+ check_defs_data *data = (check_defs_data *)data_;
+ gimple *def_stmt = SSA_NAME_DEF_STMT (vdef);
+
+ /* The ASAN_MARK intrinsic doesn't modify the variable. */
+ if (is_gimple_call (def_stmt))
+ {
+ if (gimple_call_internal_p (def_stmt)
+ && gimple_call_internal_fn (def_stmt) == IFN_ASAN_MARK)
+ return false;
+
+ if (tree fndecl = gimple_call_fndecl (def_stmt))
+ {
+ /* Some sanitizer calls pass integer arguments to built-ins
+ that expect pointers. Avoid using gimple_call_builtin_p()
+ which fails for such calls. */
+ if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
+ {
+ built_in_function fncode = DECL_FUNCTION_CODE (fndecl);
+ if (fncode > BEGIN_SANITIZER_BUILTINS
+ && fncode < END_SANITIZER_BUILTINS)
+ return false;
+ }
+ }
+ }
+
+ /* End of VLA scope is not a kill. */
+ if (gimple_call_builtin_p (def_stmt, BUILT_IN_STACK_RESTORE))
+ return false;
+
+ /* If this is a clobber then if it is not a kill walk past it. */
+ if (gimple_clobber_p (def_stmt))
+ {
+ if (stmt_kills_ref_p (def_stmt, ref))
+ return true;
+ return false;
+ }
+
+ if (builtin_call_nomodifying_p (def_stmt))
+ return false;
+
+ /* Found a may-def on this path. */
+ data->found_may_defs = true;
+ return true;
+}
+
+/* Counters and limits controlling the the depth of analysis and
+ strictness of the warning. */
+struct wlimits
+{
+ /* Number of VDEFs encountered. */
+ unsigned int vdef_cnt;
+ /* Number of statements examined by walk_aliased_vdefs. */
+ unsigned int oracle_cnt;
+ /* Limit on the number of statements visited by walk_aliased_vdefs. */
+ unsigned limit;
+ /* Set when basic block with statement is executed unconditionally. */
+ bool always_executed;
+ /* Set to issue -Wmaybe-uninitialized. */
+ bool wmaybe_uninit;
+};
+
+/* Determine if REF references an uninitialized operand and diagnose
+ it if so. STMS is the referencing statement. LHS is the result
+ of the access and may be null. RHS is the variable referenced by
+ the access; it may not be null. */
+
+static tree
+maybe_warn_operand (ao_ref &ref, gimple *stmt, tree lhs, tree rhs,
+ wlimits &wlims)
+{
+ bool has_bit_insert = false;
+ use_operand_p luse_p;
+ imm_use_iterator liter;
+
+ if (get_no_uninit_warning (rhs))
+ return NULL_TREE;
+
+ /* Do not warn if the base was marked so or this is a
+ hard register var. */
+ tree base = ao_ref_base (&ref);
+ if ((VAR_P (base)
+ && DECL_HARD_REGISTER (base))
+ || get_no_uninit_warning (base))
+ return NULL_TREE;
+
+ /* Do not warn if the access is zero size or if it's fully outside
+ the object. */
+ poly_int64 decl_size;
+ if (known_size_p (ref.size)
+ && known_eq (ref.max_size, ref.size)
+ && (known_eq (ref.size, 0)
+ || known_le (ref.offset + ref.size, 0)))
+ return NULL_TREE;
+
+ if (DECL_P (base)
+ && known_ge (ref.offset, 0)
+ && DECL_SIZE (base)
+ && poly_int_tree_p (DECL_SIZE (base), &decl_size)
+ && known_le (decl_size, ref.offset))
+ return NULL_TREE;
+
+ /* Do not warn if the result of the access is then used for
+ a BIT_INSERT_EXPR. */
+ if (lhs && TREE_CODE (lhs) == SSA_NAME)
+ FOR_EACH_IMM_USE_FAST (luse_p, liter, lhs)
+ {
+ gimple *use_stmt = USE_STMT (luse_p);
+ /* BIT_INSERT_EXPR first operand should not be considered
+ a use for the purpose of uninit warnings. */
+ if (gassign *ass = dyn_cast <gassign *> (use_stmt))
+ {
+ if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR
+ && luse_p->use == gimple_assign_rhs1_ptr (ass))
+ {
+ has_bit_insert = true;
+ break;
+ }
+ }
+ }
+
+ if (has_bit_insert)
+ return NULL_TREE;
+
+ /* Limit the walking to a constant number of stmts after
+ we overcommit quadratic behavior for small functions
+ and O(n) behavior. */
+ if (wlims.oracle_cnt > 128 * 128
+ && wlims.oracle_cnt > wlims.vdef_cnt * 2)
+ wlims.limit = 32;
+
+ check_defs_data data;
+ bool fentry_reached = false;
+ data.found_may_defs = false;
+ tree use = gimple_vuse (stmt);
+ if (!use)
+ return NULL_TREE;
+ int res = walk_aliased_vdefs (&ref, use,
+ check_defs, &data, NULL,
+ &fentry_reached, wlims.limit);
+ if (res == -1)
+ {
+ wlims.oracle_cnt += wlims.limit;
+ return NULL_TREE;
+ }
+
+ wlims.oracle_cnt += res;
+ if (data.found_may_defs)
+ return NULL_TREE;
+
+ bool found_alloc = false;
+
+ if (fentry_reached)
+ {
+ if (TREE_CODE (base) == MEM_REF)
+ base = TREE_OPERAND (base, 0);
+
+ /* Follow the chain of SSA_NAME assignments looking for an alloca
+ call (or VLA) or malloc/realloc, or for decls. If any is found
+ (and in the latter case, the operand is a local variable) issue
+ a warning. */
+ while (TREE_CODE (base) == SSA_NAME)
+ {
+ gimple *def_stmt = SSA_NAME_DEF_STMT (base);
+
+ if (is_gimple_call (def_stmt)
+ && gimple_call_builtin_p (def_stmt))
+ {
+ /* Detect uses of uninitialized alloca/VLAs. */
+ tree fndecl = gimple_call_fndecl (def_stmt);
+ const built_in_function fncode = DECL_FUNCTION_CODE (fndecl);
+ if (fncode == BUILT_IN_ALLOCA
+ || fncode == BUILT_IN_ALLOCA_WITH_ALIGN
+ || fncode == BUILT_IN_MALLOC)
+ found_alloc = true;
+ break;
+ }
+
+ if (!is_gimple_assign (def_stmt))
+ break;
+
+ tree_code code = gimple_assign_rhs_code (def_stmt);
+ if (code != ADDR_EXPR && code != POINTER_PLUS_EXPR)
+ break;
+
+ base = gimple_assign_rhs1 (def_stmt);
+ if (TREE_CODE (base) == ADDR_EXPR)
+ base = TREE_OPERAND (base, 0);
+
+ if (DECL_P (base)
+ || TREE_CODE (base) == COMPONENT_REF)
+ rhs = base;
+
+ if (TREE_CODE (base) == MEM_REF)
+ base = TREE_OPERAND (base, 0);
+
+ if (tree ba = get_base_address (base))
+ base = ba;
+ }
+
+ /* Replace the RHS expression with BASE so that it
+ refers to it in the diagnostic (instead of to
+ '<unknown>'). */
+ if (DECL_P (base)
+ && EXPR_P (rhs)
+ && TREE_CODE (rhs) != COMPONENT_REF)
+ rhs = base;
+ }
+
+ /* Do not warn if it can be initialized outside this function.
+ If we did not reach function entry then we found killing
+ clobbers on all paths to entry. */
+ if (!found_alloc && fentry_reached)
+ {
+ if (TREE_CODE (base) == SSA_NAME)
+ {
+ tree var = SSA_NAME_VAR (base);
+ if (var && TREE_CODE (var) == PARM_DECL)
+ {
+ maybe_warn_read_write_only (cfun->decl, stmt, var, rhs);
+ return NULL_TREE;
+ }
+ }
+
+ if (!VAR_P (base)
+ || is_global_var (base))
+ /* ??? We'd like to use ref_may_alias_global_p but that
+ excludes global readonly memory and thus we get bogus
+ warnings from p = cond ? "a" : "b" for example. */
+ return NULL_TREE;
+ }
+
+ /* Strip the address-of expression from arrays passed to functions. */
+ if (TREE_CODE (rhs) == ADDR_EXPR)
+ rhs = TREE_OPERAND (rhs, 0);
+
+ /* Check again since RHS may have changed above. */
+ if (get_no_uninit_warning (rhs))
+ return NULL_TREE;
+
+ /* Avoid warning about empty types such as structs with no members.
+ The first_field() test is important for C++ where the predicate
+ alone isn't always sufficient. */
+ tree rhstype = TREE_TYPE (rhs);
+ if (POINTER_TYPE_P (rhstype))
+ rhstype = TREE_TYPE (rhstype);
+ if (is_empty_type (rhstype))
+ return NULL_TREE;
+
+ bool warned = false;
+ /* We didn't find any may-defs so on all paths either
+ reached function entry or a killing clobber. */
+ location_t location
+ = linemap_resolve_location (line_table, gimple_location (stmt),
+ LRK_SPELLING_LOCATION, NULL);
+ if (wlims.always_executed)
+ {
+ if (warning_at (location, OPT_Wuninitialized,
+ "%qE is used uninitialized", rhs))
+ {
+ /* ??? This is only effective for decls as in
+ gcc.dg/uninit-B-O0.c. Avoid doing this for maybe-uninit
+ uses or accesses by functions as it may hide important
+ locations. */
+ if (lhs)
+ set_no_uninit_warning (rhs);
+ warned = true;
+ }
+ }
+ else if (wlims.wmaybe_uninit)
+ warned = warning_at (location, OPT_Wmaybe_uninitialized,
+ "%qE may be used uninitialized", rhs);
+
+ return warned ? base : NULL_TREE;
+}
+
+
+/* Diagnose passing addresses of uninitialized objects to either const
+ pointer arguments to functions, or to functions declared with attribute
+ access implying read access to those objects. */
+
+static void
+maybe_warn_pass_by_reference (gcall *stmt, wlimits &wlims)
+{
+ if (!wlims.wmaybe_uninit)
+ return;
+
+ unsigned nargs = gimple_call_num_args (stmt);
+ if (!nargs)
+ return;
+
+ tree fndecl = gimple_call_fndecl (stmt);
+ tree fntype = gimple_call_fntype (stmt);
+ if (!fntype)
+ return;
+
+ /* Const function do not read their arguments. */
+ if (gimple_call_flags (stmt) & ECF_CONST)
+ return;
+
+ const built_in_function fncode
+ = (fndecl && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)
+ ? DECL_FUNCTION_CODE (fndecl) : (built_in_function)BUILT_IN_LAST);
+
+ if (fncode == BUILT_IN_MEMCPY || fncode == BUILT_IN_MEMMOVE)
+ /* Avoid diagnosing calls to raw memory functions (this is overly
+ permissive; consider tightening it up). */
+ return;
+
+ /* Save the current warning setting and replace it either a "maybe"
+ when passing addresses of uninitialized variables to const-qualified
+ pointers or arguments declared with attribute read_write, or with
+ a "certain" when passing them to arguments declared with attribute
+ read_only. */
+ const bool save_always_executed = wlims.always_executed;
+
+ /* Initialize a map of attribute access specifications for arguments
+ to the function function call. */
+ rdwr_map rdwr_idx;
+ init_attr_rdwr_indices (&rdwr_idx, TYPE_ATTRIBUTES (fntype));
+
+ tree argtype;
+ unsigned argno = 0;
+ function_args_iterator it;
+
+ FOREACH_FUNCTION_ARGS (fntype, argtype, it)
+ {
+ ++argno;
+
+ if (!POINTER_TYPE_P (argtype))
+ continue;
+
+ tree access_size = NULL_TREE;
+ const attr_access* access = rdwr_idx.get (argno - 1);
+ if (access)
+ {
+ if (access->mode == access_none
+ || access->mode == access_write_only)
+ continue;
+
+ if (access->mode == access_deferred
+ && !TYPE_READONLY (TREE_TYPE (argtype)))
+ continue;
+
+ if (save_always_executed && access->mode == access_read_only)
+ /* Attribute read_only arguments imply read access. */
+ wlims.always_executed = true;
+ else
+ /* Attribute read_write arguments are documented as requiring
+ initialized objects but it's expected that aggregates may
+ be only partially initialized regardless. */
+ wlims.always_executed = false;
+
+ if (access->sizarg < nargs)
+ access_size = gimple_call_arg (stmt, access->sizarg);
+ }
+ else if (!TYPE_READONLY (TREE_TYPE (argtype)))
+ continue;
+ else if (save_always_executed && fncode != BUILT_IN_LAST)
+ /* Const-qualified arguments to built-ins imply read access. */
+ wlims.always_executed = true;
+ else
+ /* Const-qualified arguments to ordinary functions imply a likely
+ (but not definitive) read access. */
+ wlims.always_executed = false;
+
+ /* Ignore args we are not going to read from. */
+ if (gimple_call_arg_flags (stmt, argno - 1) & EAF_UNUSED)
+ continue;
+
+ tree arg = gimple_call_arg (stmt, argno - 1);
+ if (!POINTER_TYPE_P (TREE_TYPE (arg)))
+ /* Avoid actual arguments with invalid types. */
+ continue;
+
+ ao_ref ref;
+ ao_ref_init_from_ptr_and_size (&ref, arg, access_size);
+ tree argbase = maybe_warn_operand (ref, stmt, NULL_TREE, arg, wlims);
+ if (!argbase)
+ continue;
+
+ if (access && access->mode != access_deferred)
+ {
+ const char* const access_str =
+ TREE_STRING_POINTER (access->to_external_string ());
+
+ if (fndecl)
+ {
+ location_t loc = DECL_SOURCE_LOCATION (fndecl);
+ inform (loc, "in a call to %qD declared with "
+ "attribute %<%s%> here", fndecl, access_str);
+ }
+ else
+ {
+ /* Handle calls through function pointers. */
+ location_t loc = gimple_location (stmt);
+ inform (loc, "in a call to %qT declared with "
+ "attribute %<%s%>", fntype, access_str);
+ }
+ }
+ else
+ {
+ /* For a declaration with no relevant attribute access create
+ a dummy object and use the formatting function to avoid
+ having to complicate things here. */
+ attr_access ptr_access = { };
+ if (!access)
+ access = &ptr_access;
+ const std::string argtypestr = access->array_as_string (argtype);
+ if (fndecl)
+ {
+ location_t loc (DECL_SOURCE_LOCATION (fndecl));
+ inform (loc, "by argument %u of type %s to %qD "
+ "declared here",
+ argno, argtypestr.c_str (), fndecl);
+ }
+ else
+ {
+ /* Handle calls through function pointers. */
+ location_t loc (gimple_location (stmt));
+ inform (loc, "by argument %u of type %s to %qT",
+ argno, argtypestr.c_str (), fntype);
+ }
+ }
+
+ if (DECL_P (argbase))
+ {
+ location_t loc = DECL_SOURCE_LOCATION (argbase);
+ inform (loc, "%qD declared here", argbase);
+ }
+ }
+
+ wlims.always_executed = save_always_executed;
+}
+
+/* Warn about an uninitialized PHI argument on the fallthru path to
+ an always executed block BB. */
+
+static void
+warn_uninit_phi_uses (basic_block bb)
+{
+ edge_iterator ei;
+ edge e, found = NULL, found_back = NULL;
+ /* Look for a fallthru and possibly a single backedge. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ /* Ignore backedges. */
+ if (dominated_by_p (CDI_DOMINATORS, e->src, bb))
+ {
+ if (found_back)
+ {
+ found = NULL;
+ break;
+ }
+ found_back = e;
+ continue;
+ }
+ if (found)
+ {
+ found = NULL;
+ break;
+ }
+ found = e;
+ }
+ if (!found)
+ return;
+
+ basic_block succ = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+ for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si);
+ gsi_next (&si))
+ {
+ gphi *phi = si.phi ();
+ tree def = PHI_ARG_DEF_FROM_EDGE (phi, found);
+ if (TREE_CODE (def) != SSA_NAME
+ || !SSA_NAME_IS_DEFAULT_DEF (def)
+ || virtual_operand_p (def))
+ continue;
+ /* If there's a default def on the fallthru edge PHI
+ value and there's a use that post-dominates entry
+ then that use is uninitialized and we can warn. */
+ imm_use_iterator iter;
+ use_operand_p use_p;
+ gimple *use_stmt = NULL;
+ FOR_EACH_IMM_USE_FAST (use_p, iter, gimple_phi_result (phi))
+ {
+ use_stmt = USE_STMT (use_p);
+ if (gimple_location (use_stmt) != UNKNOWN_LOCATION
+ && dominated_by_p (CDI_POST_DOMINATORS, succ,
+ gimple_bb (use_stmt))
+ /* If we found a non-fallthru edge make sure the
+ use is inside the loop, otherwise the backedge
+ can serve as initialization. */
+ && (!found_back
+ || dominated_by_p (CDI_DOMINATORS, found_back->src,
+ gimple_bb (use_stmt))))
+ break;
+ use_stmt = NULL;
+ }
+ if (use_stmt)
+ warn_uninit (OPT_Wuninitialized, def, SSA_NAME_VAR (def),
+ SSA_NAME_VAR (def),
+ "%qD is used uninitialized", use_stmt,
+ UNKNOWN_LOCATION);
+ }
+}
+
static unsigned int
-warn_uninitialized_vars (bool warn_possibly_uninitialized)
+warn_uninitialized_vars (bool wmaybe_uninit)
{
+ /* Counters and limits controlling the the depth of the warning. */
+ wlimits wlims = { };
+ wlims.wmaybe_uninit = wmaybe_uninit;
+
gimple_stmt_iterator gsi;
basic_block bb;
-
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
- bool always_executed = dominated_by_p (CDI_POST_DOMINATORS,
- single_succ (ENTRY_BLOCK_PTR), bb);
+ basic_block succ = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+ wlims.always_executed = dominated_by_p (CDI_POST_DOMINATORS, succ, bb);
+
+ if (wlims.always_executed)
+ warn_uninit_phi_uses (bb);
+
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- gimple stmt = gsi_stmt (gsi);
+ gimple *stmt = gsi_stmt (gsi);
use_operand_p use_p;
ssa_op_iter op_iter;
tree use;
can warn about. */
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, op_iter, SSA_OP_USE)
{
+ /* BIT_INSERT_EXPR first operand should not be considered
+ a use for the purpose of uninit warnings. */
+ if (gassign *ass = dyn_cast <gassign *> (stmt))
+ {
+ if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR
+ && use_p->use == gimple_assign_rhs1_ptr (ass))
+ continue;
+ }
use = USE_FROM_PTR (use_p);
- if (always_executed)
- warn_uninit (OPT_Wuninitialized, use,
- SSA_NAME_VAR (use), SSA_NAME_VAR (use),
- "%qD is used uninitialized in this function",
- stmt);
- else if (warn_possibly_uninitialized)
- warn_uninit (OPT_Wmaybe_uninitialized, use,
- SSA_NAME_VAR (use), SSA_NAME_VAR (use),
- "%qD may be used uninitialized in this function",
- stmt);
+ if (wlims.always_executed)
+ warn_uninit (OPT_Wuninitialized, use, SSA_NAME_VAR (use),
+ SSA_NAME_VAR (use),
+ "%qD is used uninitialized", stmt,
+ UNKNOWN_LOCATION);
+ else if (wmaybe_uninit)
+ warn_uninit (OPT_Wmaybe_uninitialized, use, SSA_NAME_VAR (use),
+ SSA_NAME_VAR (use),
+ "%qD may be used uninitialized",
+ stmt, UNKNOWN_LOCATION);
}
- /* For memory the only cheap thing we can do is see if we
- have a use of the default def of the virtual operand.
- ??? Note that at -O0 we do not have virtual operands.
- ??? Not so cheap would be to use the alias oracle via
- walk_aliased_vdefs, if we don't find any aliasing vdef
- warn as is-used-uninitialized, if we don't find an aliasing
- vdef that kills our use (stmt_kills_ref_p), warn as
- may-be-used-uninitialized. But this walk is quadratic and
- so must be limited which means we would miss warning
- opportunities. */
- use = gimple_vuse (stmt);
- if (use
- && gimple_assign_single_p (stmt)
- && !gimple_vdef (stmt)
- && SSA_NAME_IS_DEFAULT_DEF (use))
+ /* For limiting the alias walk below we count all
+ vdefs in the function. */
+ if (gimple_vdef (stmt))
+ wlims.vdef_cnt++;
+
+ if (gcall *call = dyn_cast <gcall *> (stmt))
+ maybe_warn_pass_by_reference (call, wlims);
+ else if (gimple_assign_load_p (stmt)
+ && gimple_has_location (stmt))
{
tree rhs = gimple_assign_rhs1 (stmt);
- tree base = get_base_address (rhs);
+ tree lhs = gimple_assign_lhs (stmt);
- /* Do not warn if it can be initialized outside this function. */
- if (TREE_CODE (base) != VAR_DECL
- || DECL_HARD_REGISTER (base)
- || is_global_var (base))
+ ao_ref ref;
+ ao_ref_init (&ref, rhs);
+ tree var = maybe_warn_operand (ref, stmt, lhs, rhs, wlims);
+ if (!var)
continue;
- if (always_executed)
- warn_uninit (OPT_Wuninitialized, use,
- gimple_assign_rhs1 (stmt), base,
- "%qE is used uninitialized in this function",
- stmt);
- else if (warn_possibly_uninitialized)
- warn_uninit (OPT_Wmaybe_uninitialized, use,
- gimple_assign_rhs1 (stmt), base,
- "%qE may be used uninitialized in this function",
- stmt);
+ if (DECL_P (var))
+ {
+ location_t loc = DECL_SOURCE_LOCATION (var);
+ inform (loc, "%qD declared here", var);
+ }
}
}
}
return 0;
}
-/* Checks if the operand OPND of PHI is defined by
- another phi with one operand defined by this PHI,
- but the rest operands are all defined. If yes,
- returns true to skip this this operand as being
- redundant. Can be enhanced to be more general. */
+/* Checks if the operand OPND of PHI is defined by
+ another phi with one operand defined by this PHI,
+ but the rest operands are all defined. If yes,
+ returns true to skip this operand as being
+ redundant. Can be enhanced to be more general. */
static bool
-can_skip_redundant_opnd (tree opnd, gimple phi)
+can_skip_redundant_opnd (tree opnd, gimple *phi)
{
- gimple op_def;
+ gimple *op_def;
tree phi_def;
int i, n;
{
tree op = gimple_phi_arg_def (op_def, i);
if (TREE_CODE (op) != SSA_NAME)
- continue;
+ continue;
if (op != phi_def && uninit_undefined_value_p (op))
- return false;
+ return false;
}
return true;
that have empty (or possibly empty) definitions. */
static unsigned
-compute_uninit_opnds_pos (gimple phi)
+compute_uninit_opnds_pos (gphi *phi)
{
size_t i, n;
unsigned uninit_opnds = 0;
n = gimple_phi_num_args (phi);
/* Bail out for phi with too many args. */
- if (n > 32)
+ if (n > max_phi_args)
return 0;
for (i = 0; i < n; ++i)
{
tree op = gimple_phi_arg_def (phi, i);
if (TREE_CODE (op) == SSA_NAME
- && uninit_undefined_value_p (op)
- && !can_skip_redundant_opnd (op, phi))
+ && uninit_undefined_value_p (op)
+ && !can_skip_redundant_opnd (op, phi))
{
- if (cfun->has_nonlocal_label || cfun->calls_setjmp)
+ if (cfun->has_nonlocal_label || cfun->calls_setjmp)
{
/* Ignore SSA_NAMEs that appear on abnormal edges
somewhere. */
static inline basic_block
find_pdom (basic_block block)
{
- if (block == EXIT_BLOCK_PTR)
- return EXIT_BLOCK_PTR;
- else
- {
- basic_block bb
- = get_immediate_dominator (CDI_POST_DOMINATORS, block);
- if (! bb)
- return EXIT_BLOCK_PTR;
- return bb;
- }
+ if (block == EXIT_BLOCK_PTR_FOR_FN (cfun))
+ return EXIT_BLOCK_PTR_FOR_FN (cfun);
+ else
+ {
+ basic_block bb = get_immediate_dominator (CDI_POST_DOMINATORS, block);
+ if (!bb)
+ return EXIT_BLOCK_PTR_FOR_FN (cfun);
+ return bb;
+ }
}
-/* Find the immediate DOM of the specified
- basic block BLOCK. */
+/* Find the immediate DOM of the specified basic block BLOCK. */
static inline basic_block
find_dom (basic_block block)
{
- if (block == ENTRY_BLOCK_PTR)
- return ENTRY_BLOCK_PTR;
- else
- {
- basic_block bb = get_immediate_dominator (CDI_DOMINATORS, block);
- if (! bb)
- return ENTRY_BLOCK_PTR;
- return bb;
- }
+ if (block == ENTRY_BLOCK_PTR_FOR_FN (cfun))
+ return ENTRY_BLOCK_PTR_FOR_FN (cfun);
+ else
+ {
+ basic_block bb = get_immediate_dominator (CDI_DOMINATORS, block);
+ if (!bb)
+ return ENTRY_BLOCK_PTR_FOR_FN (cfun);
+ return bb;
+ }
}
/* Returns true if BB1 is postdominating BB2 and BB1 is
- not a loop exit bb. The loop exit bb check is simple and does
+ not a loop exit bb. The loop exit bb check is simple and does
not cover all cases. */
static bool
/* Find the closest postdominator of a specified BB, which is control
equivalent to BB. */
-static inline basic_block
+static inline basic_block
find_control_equiv_block (basic_block bb)
{
basic_block pdom;
#define MAX_NUM_CHAINS 8
#define MAX_CHAIN_LEN 5
#define MAX_POSTDOM_CHECK 8
+#define MAX_SWITCH_CASES 40
/* Computes the control dependence chains (paths of edges)
for DEP_BB up to the dominating basic block BB (the head node of a
- chain should be dominated by it). CD_CHAINS is pointer to a
- dynamic array holding the result chains. CUR_CD_CHAIN is the current
+ chain should be dominated by it). CD_CHAINS is pointer to an
+ array holding the result chains. CUR_CD_CHAIN is the current
chain being computed. *NUM_CHAINS is total number of chains. The
function returns true if the information is successfully computed,
return false if there is no control dependence or not computed. */
static bool
compute_control_dep_chain (basic_block bb, basic_block dep_bb,
- vec<edge> *cd_chains,
- size_t *num_chains,
- vec<edge> *cur_cd_chain)
+ vec<edge> *cd_chains,
+ size_t *num_chains,
+ vec<edge> *cur_cd_chain,
+ int *num_calls)
{
edge_iterator ei;
edge e;
bool found_cd_chain = false;
size_t cur_chain_len = 0;
- if (EDGE_COUNT (bb->succs) < 2)
+ if (*num_calls > param_uninit_control_dep_attempts)
return false;
+ ++*num_calls;
- /* Could use a set instead. */
+ /* Could use a set instead. */
cur_chain_len = cur_cd_chain->length ();
if (cur_chain_len > MAX_CHAIN_LEN)
return false;
for (i = 0; i < cur_chain_len; i++)
{
edge e = (*cur_cd_chain)[i];
- /* cycle detected. */
+ /* Cycle detected. */
if (e->src == bb)
- return false;
+ return false;
}
FOR_EACH_EDGE (e, ei, bb->succs)
basic_block cd_bb;
int post_dom_check = 0;
if (e->flags & (EDGE_FAKE | EDGE_ABNORMAL))
- continue;
+ continue;
cd_bb = e->dest;
cur_cd_chain->safe_push (e);
while (!is_non_loop_exit_postdominating (cd_bb, bb))
- {
- if (cd_bb == dep_bb)
- {
- /* Found a direct control dependence. */
- if (*num_chains < MAX_NUM_CHAINS)
- {
- cd_chains[*num_chains] = cur_cd_chain->copy ();
- (*num_chains)++;
- }
- found_cd_chain = true;
- /* check path from next edge. */
- break;
- }
-
- /* Now check if DEP_BB is indirectly control dependent on BB. */
- if (compute_control_dep_chain (cd_bb, dep_bb, cd_chains,
- num_chains, cur_cd_chain))
- {
- found_cd_chain = true;
- break;
- }
-
- cd_bb = find_pdom (cd_bb);
- post_dom_check++;
- if (cd_bb == EXIT_BLOCK_PTR || post_dom_check > MAX_POSTDOM_CHECK)
- break;
- }
+ {
+ if (cd_bb == dep_bb)
+ {
+ /* Found a direct control dependence. */
+ if (*num_chains < MAX_NUM_CHAINS)
+ {
+ cd_chains[*num_chains] = cur_cd_chain->copy ();
+ (*num_chains)++;
+ }
+ found_cd_chain = true;
+ /* Check path from next edge. */
+ break;
+ }
+
+ /* Now check if DEP_BB is indirectly control dependent on BB. */
+ if (compute_control_dep_chain (cd_bb, dep_bb, cd_chains, num_chains,
+ cur_cd_chain, num_calls))
+ {
+ found_cd_chain = true;
+ break;
+ }
+
+ cd_bb = find_pdom (cd_bb);
+ post_dom_check++;
+ if (cd_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
+ || post_dom_check > MAX_POSTDOM_CHECK)
+ break;
+ }
cur_cd_chain->pop ();
gcc_assert (cur_cd_chain->length () == cur_chain_len);
}
return found_cd_chain;
}
-typedef struct use_pred_info
+/* The type to represent a simple predicate. */
+
+struct pred_info
{
- gimple cond;
+ tree pred_lhs;
+ tree pred_rhs;
+ enum tree_code cond_code;
bool invert;
-} *use_pred_info_t;
+};
+
+/* The type to represent a sequence of predicates grouped
+ with .AND. operation. */
+
+typedef vec<pred_info, va_heap, vl_ptr> pred_chain;
+/* The type to represent a sequence of pred_chains grouped
+ with .OR. operation. */
+typedef vec<pred_chain, va_heap, vl_ptr> pred_chain_union;
/* Converts the chains of control dependence edges into a set of
- predicates. A control dependence chain is represented by a vector
- edges. DEP_CHAINS points to an array of dependence chains.
- NUM_CHAINS is the size of the chain array. One edge in a dependence
- chain is mapped to predicate expression represented by use_pred_info_t
- type. One dependence chain is converted to a composite predicate that
- is the result of AND operation of use_pred_info_t mapped to each edge.
- A composite predicate is presented by a vector of use_pred_info_t. On
+ predicates. A control dependence chain is represented by a vector
+ edges. DEP_CHAINS points to an array of dependence chains.
+ NUM_CHAINS is the size of the chain array. One edge in a dependence
+ chain is mapped to predicate expression represented by pred_info
+ type. One dependence chain is converted to a composite predicate that
+ is the result of AND operation of pred_info mapped to each edge.
+ A composite predicate is presented by a vector of pred_info. On
return, *PREDS points to the resulting array of composite predicates.
*NUM_PREDS is the number of composite predictes. */
static bool
convert_control_dep_chain_into_preds (vec<edge> *dep_chains,
- size_t num_chains,
- vec<use_pred_info_t> **preds,
- size_t *num_preds)
+ size_t num_chains,
+ pred_chain_union *preds)
{
bool has_valid_pred = false;
size_t i, j;
/* Now convert the control dep chain into a set
of predicates. */
- typedef vec<use_pred_info_t> vec_use_pred_info_t_heap;
- *preds = XCNEWVEC (vec_use_pred_info_t_heap, num_chains);
- *num_preds = num_chains;
+ preds->reserve (num_chains);
for (i = 0; i < num_chains; i++)
{
vec<edge> one_cd_chain = dep_chains[i];
has_valid_pred = false;
+ pred_chain t_chain = vNULL;
for (j = 0; j < one_cd_chain.length (); j++)
- {
- gimple cond_stmt;
- gimple_stmt_iterator gsi;
- basic_block guard_bb;
- use_pred_info_t one_pred;
- edge e;
-
- e = one_cd_chain[j];
- guard_bb = e->src;
- gsi = gsi_last_bb (guard_bb);
- if (gsi_end_p (gsi))
- {
- has_valid_pred = false;
- break;
- }
- cond_stmt = gsi_stmt (gsi);
- if (gimple_code (cond_stmt) == GIMPLE_CALL
- && EDGE_COUNT (e->src->succs) >= 2)
- {
- /* Ignore EH edge. Can add assertion
- on the other edge's flag. */
- continue;
- }
- /* Skip if there is essentially one succesor. */
- if (EDGE_COUNT (e->src->succs) == 2)
- {
- edge e1;
- edge_iterator ei1;
- bool skip = false;
-
- FOR_EACH_EDGE (e1, ei1, e->src->succs)
- {
- if (EDGE_COUNT (e1->dest->succs) == 0)
- {
- skip = true;
- break;
- }
- }
- if (skip)
- continue;
- }
- if (gimple_code (cond_stmt) != GIMPLE_COND)
- {
- has_valid_pred = false;
- break;
- }
- one_pred = XNEW (struct use_pred_info);
- one_pred->cond = cond_stmt;
- one_pred->invert = !!(e->flags & EDGE_FALSE_VALUE);
- (*preds)[i].safe_push (one_pred);
- has_valid_pred = true;
- }
+ {
+ gimple *cond_stmt;
+ gimple_stmt_iterator gsi;
+ basic_block guard_bb;
+ pred_info one_pred;
+ edge e;
+
+ e = one_cd_chain[j];
+ guard_bb = e->src;
+ gsi = gsi_last_bb (guard_bb);
+ /* Ignore empty forwarder blocks. */
+ if (empty_block_p (guard_bb) && single_succ_p (guard_bb))
+ continue;
+ /* An empty basic block here is likely a PHI, and is not one
+ of the cases we handle below. */
+ if (gsi_end_p (gsi))
+ {
+ has_valid_pred = false;
+ break;
+ }
+ cond_stmt = gsi_stmt (gsi);
+ if (is_gimple_call (cond_stmt) && EDGE_COUNT (e->src->succs) >= 2)
+ /* Ignore EH edge. Can add assertion on the other edge's flag. */
+ continue;
+ /* Skip if there is essentially one succesor. */
+ if (EDGE_COUNT (e->src->succs) == 2)
+ {
+ edge e1;
+ edge_iterator ei1;
+ bool skip = false;
+
+ FOR_EACH_EDGE (e1, ei1, e->src->succs)
+ {
+ if (EDGE_COUNT (e1->dest->succs) == 0)
+ {
+ skip = true;
+ break;
+ }
+ }
+ if (skip)
+ continue;
+ }
+ if (gimple_code (cond_stmt) == GIMPLE_COND)
+ {
+ one_pred.pred_lhs = gimple_cond_lhs (cond_stmt);
+ one_pred.pred_rhs = gimple_cond_rhs (cond_stmt);
+ one_pred.cond_code = gimple_cond_code (cond_stmt);
+ one_pred.invert = !!(e->flags & EDGE_FALSE_VALUE);
+ t_chain.safe_push (one_pred);
+ has_valid_pred = true;
+ }
+ else if (gswitch *gs = dyn_cast<gswitch *> (cond_stmt))
+ {
+ /* Avoid quadratic behavior. */
+ if (gimple_switch_num_labels (gs) > MAX_SWITCH_CASES)
+ {
+ has_valid_pred = false;
+ break;
+ }
+ /* Find the case label. */
+ tree l = NULL_TREE;
+ unsigned idx;
+ for (idx = 0; idx < gimple_switch_num_labels (gs); ++idx)
+ {
+ tree tl = gimple_switch_label (gs, idx);
+ if (e->dest == label_to_block (cfun, CASE_LABEL (tl)))
+ {
+ if (!l)
+ l = tl;
+ else
+ {
+ l = NULL_TREE;
+ break;
+ }
+ }
+ }
+ /* If more than one label reaches this block or the case
+ label doesn't have a single value (like the default one)
+ fail. */
+ if (!l
+ || !CASE_LOW (l)
+ || (CASE_HIGH (l)
+ && !operand_equal_p (CASE_LOW (l), CASE_HIGH (l), 0)))
+ {
+ has_valid_pred = false;
+ break;
+ }
+ one_pred.pred_lhs = gimple_switch_index (gs);
+ one_pred.pred_rhs = CASE_LOW (l);
+ one_pred.cond_code = EQ_EXPR;
+ one_pred.invert = false;
+ t_chain.safe_push (one_pred);
+ has_valid_pred = true;
+ }
+ else
+ {
+ has_valid_pred = false;
+ break;
+ }
+ }
if (!has_valid_pred)
- break;
+ break;
+ else
+ preds->safe_push (t_chain);
}
return has_valid_pred;
}
-/* Computes all control dependence chains for USE_BB. The control
+/* Computes all control dependence chains for USE_BB. The control
dependence chains are then converted to an array of composite
predicates pointed to by PREDS. PHI_BB is the basic block of
the phi whose result is used in USE_BB. */
static bool
-find_predicates (vec<use_pred_info_t> **preds,
- size_t *num_preds,
- basic_block phi_bb,
- basic_block use_bb)
+find_predicates (pred_chain_union *preds,
+ basic_block phi_bb,
+ basic_block use_bb)
{
size_t num_chains = 0, i;
- vec<edge> *dep_chains = 0;
- vec<edge> cur_chain = vNULL;
+ int num_calls = 0;
+ vec<edge> dep_chains[MAX_NUM_CHAINS];
+ auto_vec<edge, MAX_CHAIN_LEN + 1> cur_chain;
bool has_valid_pred = false;
basic_block cd_root = 0;
- typedef vec<edge> vec_edge_heap;
- dep_chains = XCNEWVEC (vec_edge_heap, MAX_NUM_CHAINS);
-
/* First find the closest bb that is control equivalent to PHI_BB
that also dominates USE_BB. */
cd_root = phi_bb;
{
basic_block ctrl_eq_bb = find_control_equiv_block (cd_root);
if (ctrl_eq_bb && dominated_by_p (CDI_DOMINATORS, use_bb, ctrl_eq_bb))
- cd_root = ctrl_eq_bb;
+ cd_root = ctrl_eq_bb;
else
- break;
+ break;
}
- compute_control_dep_chain (cd_root, use_bb,
- dep_chains, &num_chains,
- &cur_chain);
+ compute_control_dep_chain (cd_root, use_bb, dep_chains, &num_chains,
+ &cur_chain, &num_calls);
has_valid_pred
- = convert_control_dep_chain_into_preds (dep_chains,
- num_chains,
- preds,
- num_preds);
- /* Free individual chain */
- cur_chain.release ();
+ = convert_control_dep_chain_into_preds (dep_chains, num_chains, preds);
for (i = 0; i < num_chains; i++)
dep_chains[i].release ();
- free (dep_chains);
return has_valid_pred;
}
/* Computes the set of incoming edges of PHI that have non empty
definitions of a phi chain. The collection will be done
- recursively on operands that are defined by phis. CD_ROOT
- is the control dependence root. *EDGES holds the result, and
+ recursively on operands that are defined by phis. CD_ROOT
+ is the control dependence root. *EDGES holds the result, and
VISITED_PHIS is a pointer set for detecting cycles. */
static void
-collect_phi_def_edges (gimple phi, basic_block cd_root,
- vec<edge> *edges,
- struct pointer_set_t *visited_phis)
+collect_phi_def_edges (gphi *phi, basic_block cd_root,
+ auto_vec<edge> *edges,
+ hash_set<gimple *> *visited_phis)
{
size_t i, n;
edge opnd_edge;
tree opnd;
- if (pointer_set_insert (visited_phis, phi))
+ if (visited_phis->add (phi))
return;
n = gimple_phi_num_args (phi);
opnd = gimple_phi_arg_def (phi, i);
if (TREE_CODE (opnd) != SSA_NAME)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "\n[CHECK] Found def edge %d in ", (int)i);
- print_gimple_stmt (dump_file, phi, 0, 0);
- }
- edges->safe_push (opnd_edge);
- }
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\n[CHECK] Found def edge %d in ", (int) i);
+ print_gimple_stmt (dump_file, phi, 0);
+ }
+ edges->safe_push (opnd_edge);
+ }
else
- {
- gimple def = SSA_NAME_DEF_STMT (opnd);
-
- if (gimple_code (def) == GIMPLE_PHI
- && dominated_by_p (CDI_DOMINATORS,
- gimple_bb (def), cd_root))
- collect_phi_def_edges (def, cd_root, edges,
- visited_phis);
- else if (!uninit_undefined_value_p (opnd))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "\n[CHECK] Found def edge %d in ", (int)i);
- print_gimple_stmt (dump_file, phi, 0, 0);
- }
- edges->safe_push (opnd_edge);
- }
- }
+ {
+ gimple *def = SSA_NAME_DEF_STMT (opnd);
+
+ if (gimple_code (def) == GIMPLE_PHI
+ && dominated_by_p (CDI_DOMINATORS, gimple_bb (def), cd_root))
+ collect_phi_def_edges (as_a<gphi *> (def), cd_root, edges,
+ visited_phis);
+ else if (!uninit_undefined_value_p (opnd))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\n[CHECK] Found def edge %d in ",
+ (int) i);
+ print_gimple_stmt (dump_file, phi, 0);
+ }
+ edges->safe_push (opnd_edge);
+ }
+ }
}
}
composite predicates pointed to by PREDS. */
static bool
-find_def_preds (vec<use_pred_info_t> **preds,
- size_t *num_preds, gimple phi)
+find_def_preds (pred_chain_union *preds, gphi *phi)
{
size_t num_chains = 0, i, n;
- vec<edge> *dep_chains = 0;
- vec<edge> cur_chain = vNULL;
- vec<edge> def_edges = vNULL;
+ vec<edge> dep_chains[MAX_NUM_CHAINS];
+ auto_vec<edge, MAX_CHAIN_LEN + 1> cur_chain;
+ auto_vec<edge> def_edges;
bool has_valid_pred = false;
basic_block phi_bb, cd_root = 0;
- struct pointer_set_t *visited_phis;
-
- typedef vec<edge> vec_edge_heap;
- dep_chains = XCNEWVEC (vec_edge_heap, MAX_NUM_CHAINS);
phi_bb = gimple_bb (phi);
/* First find the closest dominating bb to be
- the control dependence root */
+ the control dependence root. */
cd_root = find_dom (phi_bb);
if (!cd_root)
return false;
- visited_phis = pointer_set_create ();
- collect_phi_def_edges (phi, cd_root, &def_edges, visited_phis);
- pointer_set_destroy (visited_phis);
+ hash_set<gimple *> visited_phis;
+ collect_phi_def_edges (phi, cd_root, &def_edges, &visited_phis);
n = def_edges.length ();
if (n == 0)
for (i = 0; i < n; i++)
{
size_t prev_nc, j;
+ int num_calls = 0;
edge opnd_edge;
opnd_edge = def_edges[i];
prev_nc = num_chains;
- compute_control_dep_chain (cd_root, opnd_edge->src,
- dep_chains, &num_chains,
- &cur_chain);
- /* Free individual chain */
- cur_chain.release ();
+ compute_control_dep_chain (cd_root, opnd_edge->src, dep_chains,
+ &num_chains, &cur_chain, &num_calls);
/* Now update the newly added chains with
- the phi operand edge: */
+ the phi operand edge: */
if (EDGE_COUNT (opnd_edge->src->succs) > 1)
- {
- if (prev_nc == num_chains
- && num_chains < MAX_NUM_CHAINS)
- num_chains++;
- for (j = prev_nc; j < num_chains; j++)
- {
- dep_chains[j].safe_push (opnd_edge);
- }
- }
+ {
+ if (prev_nc == num_chains && num_chains < MAX_NUM_CHAINS)
+ dep_chains[num_chains++] = vNULL;
+ for (j = prev_nc; j < num_chains; j++)
+ dep_chains[j].safe_push (opnd_edge);
+ }
}
has_valid_pred
- = convert_control_dep_chain_into_preds (dep_chains,
- num_chains,
- preds,
- num_preds);
+ = convert_control_dep_chain_into_preds (dep_chains, num_chains, preds);
for (i = 0; i < num_chains; i++)
dep_chains[i].release ();
- free (dep_chains);
return has_valid_pred;
}
+/* Dump a pred_info. */
+
+static void
+dump_pred_info (pred_info one_pred)
+{
+ if (one_pred.invert)
+ fprintf (dump_file, " (.NOT.) ");
+ print_generic_expr (dump_file, one_pred.pred_lhs);
+ fprintf (dump_file, " %s ", op_symbol_code (one_pred.cond_code));
+ print_generic_expr (dump_file, one_pred.pred_rhs);
+}
+
+/* Dump a pred_chain. */
+
+static void
+dump_pred_chain (pred_chain one_pred_chain)
+{
+ size_t np = one_pred_chain.length ();
+ for (size_t j = 0; j < np; j++)
+ {
+ dump_pred_info (one_pred_chain[j]);
+ if (j < np - 1)
+ fprintf (dump_file, " (.AND.) ");
+ else
+ fprintf (dump_file, "\n");
+ }
+}
+
/* Dumps the predicates (PREDS) for USESTMT. */
static void
-dump_predicates (gimple usestmt, size_t num_preds,
- vec<use_pred_info_t> *preds,
- const char* msg)
+dump_predicates (gimple *usestmt, pred_chain_union preds, const char *msg)
{
- size_t i, j;
- vec<use_pred_info_t> one_pred_chain;
- fprintf (dump_file, msg);
- print_gimple_stmt (dump_file, usestmt, 0, 0);
- fprintf (dump_file, "is guarded by :\n");
- /* do some dumping here: */
- for (i = 0; i < num_preds; i++)
- {
- size_t np;
-
- one_pred_chain = preds[i];
- np = one_pred_chain.length ();
-
- for (j = 0; j < np; j++)
- {
- use_pred_info_t one_pred
- = one_pred_chain[j];
- if (one_pred->invert)
- fprintf (dump_file, " (.NOT.) ");
- print_gimple_stmt (dump_file, one_pred->cond, 0, 0);
- if (j < np - 1)
- fprintf (dump_file, "(.AND.)\n");
- }
+ fprintf (dump_file, "%s", msg);
+ if (usestmt)
+ {
+ print_gimple_stmt (dump_file, usestmt, 0);
+ fprintf (dump_file, "is guarded by :\n\n");
+ }
+ size_t num_preds = preds.length ();
+ for (size_t i = 0; i < num_preds; i++)
+ {
+ dump_pred_chain (preds[i]);
if (i < num_preds - 1)
- fprintf (dump_file, "(.OR.)\n");
+ fprintf (dump_file, "(.OR.)\n");
+ else
+ fprintf (dump_file, "\n\n");
}
}
/* Destroys the predicate set *PREDS. */
static void
-destroy_predicate_vecs (size_t n,
- vec<use_pred_info_t> * preds)
+destroy_predicate_vecs (pred_chain_union *preds)
{
- size_t i, j;
+ size_t i;
+
+ size_t n = preds->length ();
for (i = 0; i < n; i++)
- {
- for (j = 0; j < preds[i].length (); j++)
- free (preds[i][j]);
- preds[i].release ();
- }
- free (preds);
+ (*preds)[i].release ();
+ preds->release ();
}
-
-/* Computes the 'normalized' conditional code with operand
+/* Computes the 'normalized' conditional code with operand
swapping and condition inversion. */
static enum tree_code
-get_cmp_code (enum tree_code orig_cmp_code,
- bool swap_cond, bool invert)
+get_cmp_code (enum tree_code orig_cmp_code, bool swap_cond, bool invert)
{
enum tree_code tc = orig_cmp_code;
return tc;
}
-/* Returns true if VAL falls in the range defined by BOUNDARY and CMPC, i.e.
- all values in the range satisfies (x CMPC BOUNDARY) == true. */
+/* Returns whether VAL CMPC BOUNDARY is true. */
static bool
is_value_included_in (tree val, tree boundary, enum tree_code cmpc)
{
bool inverted = false;
- bool is_unsigned;
bool result;
/* Only handle integer constant here. */
- if (TREE_CODE (val) != INTEGER_CST
- || TREE_CODE (boundary) != INTEGER_CST)
+ if (TREE_CODE (val) != INTEGER_CST || TREE_CODE (boundary) != INTEGER_CST)
return true;
- is_unsigned = TYPE_UNSIGNED (TREE_TYPE (val));
-
- if (cmpc == GE_EXPR || cmpc == GT_EXPR
- || cmpc == NE_EXPR)
+ if (cmpc == GE_EXPR || cmpc == GT_EXPR || cmpc == NE_EXPR)
{
cmpc = invert_tree_comparison (cmpc, false);
inverted = true;
}
- if (is_unsigned)
- {
- if (cmpc == EQ_EXPR)
- result = tree_int_cst_equal (val, boundary);
- else if (cmpc == LT_EXPR)
- result = INT_CST_LT_UNSIGNED (val, boundary);
- else
- {
- gcc_assert (cmpc == LE_EXPR);
- result = (tree_int_cst_equal (val, boundary)
- || INT_CST_LT_UNSIGNED (val, boundary));
- }
- }
+ if (cmpc == EQ_EXPR)
+ result = tree_int_cst_equal (val, boundary);
+ else if (cmpc == LT_EXPR)
+ result = tree_int_cst_lt (val, boundary);
else
{
- if (cmpc == EQ_EXPR)
- result = tree_int_cst_equal (val, boundary);
- else if (cmpc == LT_EXPR)
- result = INT_CST_LT (val, boundary);
- else
- {
- gcc_assert (cmpc == LE_EXPR);
- result = (tree_int_cst_equal (val, boundary)
- || INT_CST_LT (val, boundary));
- }
+ gcc_assert (cmpc == LE_EXPR);
+ result = tree_int_cst_le (val, boundary);
}
if (inverted)
return result;
}
+/* Returns whether VAL satisfies (x CMPC BOUNDARY) predicate. CMPC can be
+ either one of the range comparison codes ({GE,LT,EQ,NE}_EXPR and the like),
+ or BIT_AND_EXPR. EXACT_P is only meaningful for the latter. It modifies the
+ question from whether VAL & BOUNDARY != 0 to whether VAL & BOUNDARY == VAL.
+ For other values of CMPC, EXACT_P is ignored. */
+
+static bool
+value_sat_pred_p (tree val, tree boundary, enum tree_code cmpc,
+ bool exact_p = false)
+{
+ if (cmpc != BIT_AND_EXPR)
+ return is_value_included_in (val, boundary, cmpc);
+
+ wide_int andw = wi::to_wide (val) & wi::to_wide (boundary);
+ if (exact_p)
+ return andw == wi::to_wide (val);
+ else
+ return andw.to_uhwi ();
+}
+
/* Returns true if PRED is common among all the predicate
- chains (PREDS) (and therefore can be factored out).
- NUM_PRED_CHAIN is the size of array PREDS. */
+ chains (PREDS) (and therefore can be factored out). */
static bool
-find_matching_predicate_in_rest_chains (use_pred_info_t pred,
- vec<use_pred_info_t> *preds,
- size_t num_pred_chains)
+find_matching_predicate_in_rest_chains (pred_info pred, pred_chain_union preds)
{
size_t i, j, n;
- /* trival case */
- if (num_pred_chains == 1)
+ /* Trival case. */
+ if (preds.length () == 1)
return true;
- for (i = 1; i < num_pred_chains; i++)
+ for (i = 1; i < preds.length (); i++)
{
bool found = false;
- vec<use_pred_info_t> one_chain = preds[i];
+ pred_chain one_chain = preds[i];
n = one_chain.length ();
for (j = 0; j < n; j++)
- {
- use_pred_info_t pred2
- = one_chain[j];
- /* can relax the condition comparison to not
- use address comparison. However, the most common
- case is that multiple control dependent paths share
- a common path prefix, so address comparison should
- be ok. */
-
- if (pred2->cond == pred->cond
- && pred2->invert == pred->invert)
- {
- found = true;
- break;
- }
- }
+ {
+ pred_info pred2 = one_chain[j];
+ /* Can relax the condition comparison to not
+ use address comparison. However, the most common
+ case is that multiple control dependent paths share
+ a common path prefix, so address comparison should
+ be ok. */
+
+ if (operand_equal_p (pred2.pred_lhs, pred.pred_lhs, 0)
+ && operand_equal_p (pred2.pred_rhs, pred.pred_rhs, 0)
+ && pred2.invert == pred.invert)
+ {
+ found = true;
+ break;
+ }
+ }
if (!found)
- return false;
+ return false;
}
return true;
}
/* Forward declaration. */
-static bool
-is_use_properly_guarded (gimple use_stmt,
- basic_block use_bb,
- gimple phi,
- unsigned uninit_opnds,
- struct pointer_set_t *visited_phis);
-
-/* Returns true if all uninitialized opnds are pruned. Returns false
- otherwise. PHI is the phi node with uninitialized operands,
+static bool is_use_properly_guarded (gimple *use_stmt,
+ basic_block use_bb,
+ gphi *phi,
+ unsigned uninit_opnds,
+ pred_chain_union *def_preds,
+ hash_set<gphi *> *visited_phis);
+
+/* Returns true if all uninitialized opnds are pruned. Returns false
+ otherwise. PHI is the phi node with uninitialized operands,
UNINIT_OPNDS is the bitmap of the uninitialize operand positions,
FLAG_DEF is the statement defining the flag guarding the use of the
PHI output, BOUNDARY_CST is the const value used in the predicate
Example scenario:
BB1:
- flag_1 = phi <0, 1> // (1)
+ flag_1 = phi <0, 1> // (1)
var_1 = phi <undef, some_val>
goto BB3;
BB3:
- use of var_2 // (3)
+ use of var_2 // (3)
Because some flag arg in (1) is not constant, if we do not look into the
flag phis recursively, it is conservatively treated as unknown and var_1
- is thought to be flowed into use at (3). Since var_1 is potentially uninitialized
- a false warning will be emitted. Checking recursively into (1), the compiler can
- find out that only some_val (which is defined) can flow into (3) which is OK.
-
-*/
+ is thought to be flowed into use at (3). Since var_1 is potentially
+ uninitialized a false warning will be emitted.
+ Checking recursively into (1), the compiler can find out that only some_val
+ (which is defined) can flow into (3) which is OK. */
static bool
-prune_uninit_phi_opnds_in_unrealizable_paths (
- gimple phi, unsigned uninit_opnds,
- gimple flag_def, tree boundary_cst,
- enum tree_code cmp_code,
- struct pointer_set_t *visited_phis,
- bitmap *visited_flag_phis)
+prune_uninit_phi_opnds (gphi *phi, unsigned uninit_opnds, gphi *flag_def,
+ tree boundary_cst, enum tree_code cmp_code,
+ hash_set<gphi *> *visited_phis,
+ bitmap *visited_flag_phis)
{
unsigned i;
- for (i = 0; i < MIN (32, gimple_phi_num_args (flag_def)); i++)
+ for (i = 0; i < MIN (max_phi_args, gimple_phi_num_args (flag_def)); i++)
{
tree flag_arg;
if (!MASK_TEST_BIT (uninit_opnds, i))
- continue;
+ continue;
flag_arg = gimple_phi_arg_def (flag_def, i);
if (!is_gimple_constant (flag_arg))
- {
- gimple flag_arg_def, phi_arg_def;
- tree phi_arg;
- unsigned uninit_opnds_arg_phi;
-
- if (TREE_CODE (flag_arg) != SSA_NAME)
- return false;
- flag_arg_def = SSA_NAME_DEF_STMT (flag_arg);
- if (gimple_code (flag_arg_def) != GIMPLE_PHI)
- return false;
-
- phi_arg = gimple_phi_arg_def (phi, i);
- if (TREE_CODE (phi_arg) != SSA_NAME)
- return false;
-
- phi_arg_def = SSA_NAME_DEF_STMT (phi_arg);
- if (gimple_code (phi_arg_def) != GIMPLE_PHI)
- return false;
-
- if (gimple_bb (phi_arg_def) != gimple_bb (flag_arg_def))
- return false;
-
- if (!*visited_flag_phis)
- *visited_flag_phis = BITMAP_ALLOC (NULL);
-
- if (bitmap_bit_p (*visited_flag_phis,
- SSA_NAME_VERSION (gimple_phi_result (flag_arg_def))))
- return false;
-
- bitmap_set_bit (*visited_flag_phis,
- SSA_NAME_VERSION (gimple_phi_result (flag_arg_def)));
-
- /* Now recursively prune the uninitialized phi args. */
- uninit_opnds_arg_phi = compute_uninit_opnds_pos (phi_arg_def);
- if (!prune_uninit_phi_opnds_in_unrealizable_paths (
- phi_arg_def, uninit_opnds_arg_phi,
- flag_arg_def, boundary_cst, cmp_code,
- visited_phis, visited_flag_phis))
- return false;
-
- bitmap_clear_bit (*visited_flag_phis,
- SSA_NAME_VERSION (gimple_phi_result (flag_arg_def)));
- continue;
- }
+ {
+ gphi *flag_arg_def, *phi_arg_def;
+ tree phi_arg;
+ unsigned uninit_opnds_arg_phi;
+
+ if (TREE_CODE (flag_arg) != SSA_NAME)
+ return false;
+ flag_arg_def = dyn_cast<gphi *> (SSA_NAME_DEF_STMT (flag_arg));
+ if (!flag_arg_def)
+ return false;
+
+ phi_arg = gimple_phi_arg_def (phi, i);
+ if (TREE_CODE (phi_arg) != SSA_NAME)
+ return false;
+
+ phi_arg_def = dyn_cast<gphi *> (SSA_NAME_DEF_STMT (phi_arg));
+ if (!phi_arg_def)
+ return false;
+
+ if (gimple_bb (phi_arg_def) != gimple_bb (flag_arg_def))
+ return false;
+
+ if (!*visited_flag_phis)
+ *visited_flag_phis = BITMAP_ALLOC (NULL);
+
+ tree phi_result = gimple_phi_result (flag_arg_def);
+ if (bitmap_bit_p (*visited_flag_phis, SSA_NAME_VERSION (phi_result)))
+ return false;
+
+ bitmap_set_bit (*visited_flag_phis,
+ SSA_NAME_VERSION (gimple_phi_result (flag_arg_def)));
+
+ /* Now recursively prune the uninitialized phi args. */
+ uninit_opnds_arg_phi = compute_uninit_opnds_pos (phi_arg_def);
+ if (!prune_uninit_phi_opnds
+ (phi_arg_def, uninit_opnds_arg_phi, flag_arg_def, boundary_cst,
+ cmp_code, visited_phis, visited_flag_phis))
+ return false;
+
+ phi_result = gimple_phi_result (flag_arg_def);
+ bitmap_clear_bit (*visited_flag_phis, SSA_NAME_VERSION (phi_result));
+ continue;
+ }
/* Now check if the constant is in the guarded range. */
if (is_value_included_in (flag_arg, boundary_cst, cmp_code))
- {
- tree opnd;
- gimple opnd_def;
-
- /* Now that we know that this undefined edge is not
- pruned. If the operand is defined by another phi,
- we can further prune the incoming edges of that
- phi by checking the predicates of this operands. */
-
- opnd = gimple_phi_arg_def (phi, i);
- opnd_def = SSA_NAME_DEF_STMT (opnd);
- if (gimple_code (opnd_def) == GIMPLE_PHI)
- {
- edge opnd_edge;
- unsigned uninit_opnds2
- = compute_uninit_opnds_pos (opnd_def);
- gcc_assert (!MASK_EMPTY (uninit_opnds2));
- opnd_edge = gimple_phi_arg_edge (phi, i);
- if (!is_use_properly_guarded (phi,
- opnd_edge->src,
- opnd_def,
- uninit_opnds2,
- visited_phis))
- return false;
- }
- else
- return false;
- }
+ {
+ tree opnd;
+ gimple *opnd_def;
+
+ /* Now that we know that this undefined edge is not
+ pruned. If the operand is defined by another phi,
+ we can further prune the incoming edges of that
+ phi by checking the predicates of this operands. */
+
+ opnd = gimple_phi_arg_def (phi, i);
+ opnd_def = SSA_NAME_DEF_STMT (opnd);
+ if (gphi *opnd_def_phi = dyn_cast <gphi *> (opnd_def))
+ {
+ edge opnd_edge;
+ unsigned uninit_opnds2 = compute_uninit_opnds_pos (opnd_def_phi);
+ if (!MASK_EMPTY (uninit_opnds2))
+ {
+ pred_chain_union def_preds = vNULL;
+ bool ok;
+ opnd_edge = gimple_phi_arg_edge (phi, i);
+ ok = is_use_properly_guarded (phi,
+ opnd_edge->src,
+ opnd_def_phi,
+ uninit_opnds2,
+ &def_preds,
+ visited_phis);
+ destroy_predicate_vecs (&def_preds);
+ if (!ok)
+ return false;
+ }
+ }
+ else
+ return false;
+ }
}
return true;
}
+/* A helper function finds predicate which will be examined against uninit
+ paths. If there is no "flag_var cmp const" form predicate, the function
+ tries to find predicate of form like "flag_var cmp flag_var" with value
+ range info. PHI is the phi node whose incoming (undefined) paths need to
+ be examined. On success, the function returns the comparsion code, sets
+ defintion gimple of the flag_var to FLAG_DEF, sets boundary_cst to
+ BOUNDARY_CST. On fail, the function returns ERROR_MARK. */
+
+static enum tree_code
+find_var_cmp_const (pred_chain_union preds, gphi *phi, gimple **flag_def,
+ tree *boundary_cst)
+{
+ enum tree_code vrinfo_code = ERROR_MARK, code;
+ gimple *vrinfo_def = NULL;
+ tree vrinfo_cst = NULL, cond_lhs, cond_rhs;
+
+ gcc_assert (preds.length () > 0);
+ pred_chain the_pred_chain = preds[0];
+ for (unsigned i = 0; i < the_pred_chain.length (); i++)
+ {
+ bool use_vrinfo_p = false;
+ pred_info the_pred = the_pred_chain[i];
+ cond_lhs = the_pred.pred_lhs;
+ cond_rhs = the_pred.pred_rhs;
+ if (cond_lhs == NULL_TREE || cond_rhs == NULL_TREE)
+ continue;
+
+ code = get_cmp_code (the_pred.cond_code, false, the_pred.invert);
+ if (code == ERROR_MARK)
+ continue;
+
+ if (TREE_CODE (cond_lhs) == SSA_NAME && is_gimple_constant (cond_rhs))
+ ;
+ else if (TREE_CODE (cond_rhs) == SSA_NAME
+ && is_gimple_constant (cond_lhs))
+ {
+ std::swap (cond_lhs, cond_rhs);
+ if ((code = get_cmp_code (code, true, false)) == ERROR_MARK)
+ continue;
+ }
+ /* Check if we can take advantage of "flag_var comp flag_var" predicate
+ with value range info. Note only first of such case is handled. */
+ else if (vrinfo_code == ERROR_MARK
+ && TREE_CODE (cond_lhs) == SSA_NAME
+ && TREE_CODE (cond_rhs) == SSA_NAME)
+ {
+ gimple* lhs_def = SSA_NAME_DEF_STMT (cond_lhs);
+ if (!lhs_def || gimple_code (lhs_def) != GIMPLE_PHI
+ || gimple_bb (lhs_def) != gimple_bb (phi))
+ {
+ std::swap (cond_lhs, cond_rhs);
+ if ((code = get_cmp_code (code, true, false)) == ERROR_MARK)
+ continue;
+ }
+
+ /* Check value range info of rhs, do following transforms:
+ flag_var < [min, max] -> flag_var < max
+ flag_var > [min, max] -> flag_var > min
+
+ We can also transform LE_EXPR/GE_EXPR to LT_EXPR/GT_EXPR:
+ flag_var <= [min, max] -> flag_var < [min, max+1]
+ flag_var >= [min, max] -> flag_var > [min-1, max]
+ if no overflow/wrap. */
+ tree type = TREE_TYPE (cond_lhs);
+ value_range r;
+ if (!INTEGRAL_TYPE_P (type)
+ || !get_range_query (cfun)->range_of_expr (r, cond_rhs)
+ || r.kind () != VR_RANGE)
+ continue;
+ wide_int min = r.lower_bound ();
+ wide_int max = r.upper_bound ();
+ if (code == LE_EXPR
+ && max != wi::max_value (TYPE_PRECISION (type), TYPE_SIGN (type)))
+ {
+ code = LT_EXPR;
+ max = max + 1;
+ }
+ if (code == GE_EXPR
+ && min != wi::min_value (TYPE_PRECISION (type), TYPE_SIGN (type)))
+ {
+ code = GT_EXPR;
+ min = min - 1;
+ }
+ if (code == LT_EXPR)
+ cond_rhs = wide_int_to_tree (type, max);
+ else if (code == GT_EXPR)
+ cond_rhs = wide_int_to_tree (type, min);
+ else
+ continue;
+
+ use_vrinfo_p = true;
+ }
+ else
+ continue;
+
+ if ((*flag_def = SSA_NAME_DEF_STMT (cond_lhs)) == NULL)
+ continue;
+
+ if (gimple_code (*flag_def) != GIMPLE_PHI
+ || gimple_bb (*flag_def) != gimple_bb (phi)
+ || !find_matching_predicate_in_rest_chains (the_pred, preds))
+ continue;
+
+ /* Return if any "flag_var comp const" predicate is found. */
+ if (!use_vrinfo_p)
+ {
+ *boundary_cst = cond_rhs;
+ return code;
+ }
+ /* Record if any "flag_var comp flag_var[vinfo]" predicate is found. */
+ else if (vrinfo_code == ERROR_MARK)
+ {
+ vrinfo_code = code;
+ vrinfo_def = *flag_def;
+ vrinfo_cst = cond_rhs;
+ }
+ }
+ /* Return the "flag_var cmp flag_var[vinfo]" predicate we found. */
+ if (vrinfo_code != ERROR_MARK)
+ {
+ *flag_def = vrinfo_def;
+ *boundary_cst = vrinfo_cst;
+ }
+ return vrinfo_code;
+}
+
/* A helper function that determines if the predicate set
of the use is not overlapping with that of the uninit paths.
The most common senario of guarded use is in Example 1:
Example 1:
- if (some_cond)
- {
- x = ...;
- flag = true;
- }
+ if (some_cond)
+ {
+ x = ...;
+ flag = true;
+ }
- ... some code ...
+ ... some code ...
- if (flag)
- use (x);
+ if (flag)
+ use (x);
The real world examples are usually more complicated, but similar
and usually result from inlining:
- bool init_func (int * x)
- {
- if (some_cond)
- return false;
- *x = ..
- return true;
- }
+ bool init_func (int * x)
+ {
+ if (some_cond)
+ return false;
+ *x = ..
+ return true;
+ }
- void foo(..)
- {
- int x;
+ void foo (..)
+ {
+ int x;
- if (!init_func(&x))
- return;
+ if (!init_func (&x))
+ return;
- .. some_code ...
- use (x);
- }
+ .. some_code ...
+ use (x);
+ }
Another possible use scenario is in the following trivial example:
Example 2:
- if (n > 0)
- x = 1;
- ...
- if (n > 0)
- {
- if (m < 2)
- .. = x;
- }
+ if (n > 0)
+ x = 1;
+ ...
+ if (n > 0)
+ {
+ if (m < 2)
+ .. = x;
+ }
Predicate analysis needs to compute the composite predicate:
bb and is dominating the operand def.)
and check overlapping:
- (n > 0) .AND. (m < 2) .AND. (.NOT. (n > 0))
- <==> false
+ (n > 0) .AND. (m < 2) .AND. (.NOT. (n > 0))
+ <==> false
This implementation provides framework that can handle
- scenarios. (Note that many simple cases are handled properly
+ scenarios. (Note that many simple cases are handled properly
without the predicate analysis -- this is due to jump threading
transformation which eliminates the merge point thus makes
path sensitive analysis unnecessary.)
- NUM_PREDS is the number is the number predicate chains, PREDS is
- the array of chains, PHI is the phi node whose incoming (undefined)
- paths need to be pruned, and UNINIT_OPNDS is the bitmap holding
- uninit operand positions. VISITED_PHIS is the pointer set of phi
- stmts being checked. */
-
+ PHI is the phi node whose incoming (undefined) paths need to be
+ pruned, and UNINIT_OPNDS is the bitmap holding uninit operand
+ positions. VISITED_PHIS is the pointer set of phi stmts being
+ checked. */
static bool
-use_pred_not_overlap_with_undef_path_pred (
- size_t num_preds,
- vec<use_pred_info_t> *preds,
- gimple phi, unsigned uninit_opnds,
- struct pointer_set_t *visited_phis)
-{
- unsigned int i, n;
- gimple flag_def = 0;
- tree boundary_cst = 0;
+use_pred_not_overlap_with_undef_path_pred (pred_chain_union preds,
+ gphi *phi, unsigned uninit_opnds,
+ hash_set<gphi *> *visited_phis)
+{
+ gimple *flag_def = 0;
+ tree boundary_cst = 0;
enum tree_code cmp_code;
- bool swap_cond = false;
- bool invert = false;
- vec<use_pred_info_t> the_pred_chain;
bitmap visited_flag_phis = NULL;
bool all_pruned = false;
- gcc_assert (num_preds > 0);
/* Find within the common prefix of multiple predicate chains
a predicate that is a comparison of a flag variable against
a constant. */
- the_pred_chain = preds[0];
- n = the_pred_chain.length ();
- for (i = 0; i < n; i++)
- {
- gimple cond;
- tree cond_lhs, cond_rhs, flag = 0;
-
- use_pred_info_t the_pred
- = the_pred_chain[i];
-
- cond = the_pred->cond;
- invert = the_pred->invert;
- cond_lhs = gimple_cond_lhs (cond);
- cond_rhs = gimple_cond_rhs (cond);
- cmp_code = gimple_cond_code (cond);
-
- if (cond_lhs != NULL_TREE && TREE_CODE (cond_lhs) == SSA_NAME
- && cond_rhs != NULL_TREE && is_gimple_constant (cond_rhs))
- {
- boundary_cst = cond_rhs;
- flag = cond_lhs;
- }
- else if (cond_rhs != NULL_TREE && TREE_CODE (cond_rhs) == SSA_NAME
- && cond_lhs != NULL_TREE && is_gimple_constant (cond_lhs))
- {
- boundary_cst = cond_lhs;
- flag = cond_rhs;
- swap_cond = true;
- }
-
- if (!flag)
- continue;
-
- flag_def = SSA_NAME_DEF_STMT (flag);
-
- if (!flag_def)
- continue;
-
- if ((gimple_code (flag_def) == GIMPLE_PHI)
- && (gimple_bb (flag_def) == gimple_bb (phi))
- && find_matching_predicate_in_rest_chains (
- the_pred, preds, num_preds))
- break;
-
- flag_def = 0;
- }
-
- if (!flag_def)
+ cmp_code = find_var_cmp_const (preds, phi, &flag_def, &boundary_cst);
+ if (cmp_code == ERROR_MARK)
return false;
/* Now check all the uninit incoming edge has a constant flag value
that is in conflict with the use guard/predicate. */
- cmp_code = get_cmp_code (cmp_code, swap_cond, invert);
-
- if (cmp_code == ERROR_MARK)
- return false;
-
- all_pruned = prune_uninit_phi_opnds_in_unrealizable_paths (phi,
- uninit_opnds,
- flag_def,
- boundary_cst,
- cmp_code,
- visited_phis,
- &visited_flag_phis);
+ all_pruned = prune_uninit_phi_opnds
+ (phi, uninit_opnds, as_a<gphi *> (flag_def), boundary_cst, cmp_code,
+ visited_phis, &visited_flag_phis);
if (visited_flag_phis)
BITMAP_FREE (visited_flag_phis);
return all_pruned;
}
-/* Returns true if TC is AND or OR */
+/* The helper function returns true if two predicates X1 and X2
+ are equivalent. It assumes the expressions have already
+ properly re-associated. */
static inline bool
-is_and_or_or (enum tree_code tc, tree typ)
+pred_equal_p (pred_info x1, pred_info x2)
{
- return (tc == BIT_IOR_EXPR
- || (tc == BIT_AND_EXPR
- && (typ == 0 || TREE_CODE (typ) == BOOLEAN_TYPE)));
-}
+ enum tree_code c1, c2;
+ if (!operand_equal_p (x1.pred_lhs, x2.pred_lhs, 0)
+ || !operand_equal_p (x1.pred_rhs, x2.pred_rhs, 0))
+ return false;
-typedef struct norm_cond
-{
- vec<gimple> conds;
- enum tree_code cond_code;
- bool invert;
-} *norm_cond_t;
+ c1 = x1.cond_code;
+ if (x1.invert != x2.invert
+ && TREE_CODE_CLASS (x2.cond_code) == tcc_comparison)
+ c2 = invert_tree_comparison (x2.cond_code, false);
+ else
+ c2 = x2.cond_code;
+ return c1 == c2;
+}
-/* Normalizes gimple condition COND. The normalization follows
- UD chains to form larger condition expression trees. NORM_COND
- holds the normalized result. COND_CODE is the logical opcode
- (AND or OR) of the normalized tree. */
+/* Returns true if the predication is testing !=. */
-static void
-normalize_cond_1 (gimple cond,
- norm_cond_t norm_cond,
- enum tree_code cond_code)
+static inline bool
+is_neq_relop_p (pred_info pred)
{
- enum gimple_code gc;
- enum tree_code cur_cond_code;
- tree rhs1, rhs2;
-
- gc = gimple_code (cond);
- if (gc != GIMPLE_ASSIGN)
- {
- norm_cond->conds.safe_push (cond);
- return;
- }
- cur_cond_code = gimple_assign_rhs_code (cond);
- rhs1 = gimple_assign_rhs1 (cond);
- rhs2 = gimple_assign_rhs2 (cond);
- if (cur_cond_code == NE_EXPR)
- {
- if (integer_zerop (rhs2)
- && (TREE_CODE (rhs1) == SSA_NAME))
- normalize_cond_1 (
- SSA_NAME_DEF_STMT (rhs1),
- norm_cond, cond_code);
- else if (integer_zerop (rhs1)
- && (TREE_CODE (rhs2) == SSA_NAME))
- normalize_cond_1 (
- SSA_NAME_DEF_STMT (rhs2),
- norm_cond, cond_code);
- else
- norm_cond->conds.safe_push (cond);
+ return ((pred.cond_code == NE_EXPR && !pred.invert)
+ || (pred.cond_code == EQ_EXPR && pred.invert));
+}
- return;
- }
+/* Returns true if pred is of the form X != 0. */
- if (is_and_or_or (cur_cond_code, TREE_TYPE (rhs1))
- && (cond_code == cur_cond_code || cond_code == ERROR_MARK)
- && (TREE_CODE (rhs1) == SSA_NAME && TREE_CODE (rhs2) == SSA_NAME))
- {
- normalize_cond_1 (SSA_NAME_DEF_STMT (rhs1),
- norm_cond, cur_cond_code);
- normalize_cond_1 (SSA_NAME_DEF_STMT (rhs2),
- norm_cond, cur_cond_code);
- norm_cond->cond_code = cur_cond_code;
- }
- else
- norm_cond->conds.safe_push (cond);
+static inline bool
+is_neq_zero_form_p (pred_info pred)
+{
+ if (!is_neq_relop_p (pred) || !integer_zerop (pred.pred_rhs)
+ || TREE_CODE (pred.pred_lhs) != SSA_NAME)
+ return false;
+ return true;
}
-/* See normalize_cond_1 for details. INVERT is a flag to indicate
- if COND needs to be inverted or not. */
+/* The helper function returns true if two predicates X1
+ is equivalent to X2 != 0. */
-static void
-normalize_cond (gimple cond, norm_cond_t norm_cond, bool invert)
+static inline bool
+pred_expr_equal_p (pred_info x1, tree x2)
{
- enum tree_code cond_code;
-
- norm_cond->cond_code = ERROR_MARK;
- norm_cond->invert = false;
- norm_cond->conds.create (0);
- gcc_assert (gimple_code (cond) == GIMPLE_COND);
- cond_code = gimple_cond_code (cond);
- if (invert)
- cond_code = invert_tree_comparison (cond_code, false);
-
- if (cond_code == NE_EXPR)
- {
- if (integer_zerop (gimple_cond_rhs (cond))
- && (TREE_CODE (gimple_cond_lhs (cond)) == SSA_NAME))
- normalize_cond_1 (
- SSA_NAME_DEF_STMT (gimple_cond_lhs (cond)),
- norm_cond, ERROR_MARK);
- else if (integer_zerop (gimple_cond_lhs (cond))
- && (TREE_CODE (gimple_cond_rhs (cond)) == SSA_NAME))
- normalize_cond_1 (
- SSA_NAME_DEF_STMT (gimple_cond_rhs (cond)),
- norm_cond, ERROR_MARK);
- else
- {
- norm_cond->conds.safe_push (cond);
- norm_cond->invert = invert;
- }
- }
- else
- {
- norm_cond->conds.safe_push (cond);
- norm_cond->invert = invert;
- }
+ if (!is_neq_zero_form_p (x1))
+ return false;
- gcc_assert (norm_cond->conds.length () == 1
- || is_and_or_or (norm_cond->cond_code, NULL));
+ return operand_equal_p (x1.pred_lhs, x2, 0);
}
-/* Returns true if the domain for condition COND1 is a subset of
- COND2. REVERSE is a flag. when it is true the function checks
- if COND1 is a superset of COND2. INVERT1 and INVERT2 are flags
- to indicate if COND1 and COND2 need to be inverted or not. */
+/* Returns true of the domain of single predicate expression
+ EXPR1 is a subset of that of EXPR2. Returns false if it
+ cannot be proved. */
static bool
-is_gcond_subset_of (gimple cond1, bool invert1,
- gimple cond2, bool invert2,
- bool reverse)
+is_pred_expr_subset_of (pred_info expr1, pred_info expr2)
{
- enum gimple_code gc1, gc2;
- enum tree_code cond1_code, cond2_code;
- gimple tmp;
- tree cond1_lhs, cond1_rhs, cond2_lhs, cond2_rhs;
+ enum tree_code code1, code2;
- /* Take the short cut. */
- if (cond1 == cond2)
+ if (pred_equal_p (expr1, expr2))
return true;
- if (reverse)
- {
- tmp = cond1;
- cond1 = cond2;
- cond2 = tmp;
- }
-
- gc1 = gimple_code (cond1);
- gc2 = gimple_code (cond2);
-
- if ((gc1 != GIMPLE_ASSIGN && gc1 != GIMPLE_COND)
- || (gc2 != GIMPLE_ASSIGN && gc2 != GIMPLE_COND))
- return cond1 == cond2;
-
- cond1_code = ((gc1 == GIMPLE_ASSIGN)
- ? gimple_assign_rhs_code (cond1)
- : gimple_cond_code (cond1));
-
- cond2_code = ((gc2 == GIMPLE_ASSIGN)
- ? gimple_assign_rhs_code (cond2)
- : gimple_cond_code (cond2));
-
- if (TREE_CODE_CLASS (cond1_code) != tcc_comparison
- || TREE_CODE_CLASS (cond2_code) != tcc_comparison)
+ if ((TREE_CODE (expr1.pred_rhs) != INTEGER_CST)
+ || (TREE_CODE (expr2.pred_rhs) != INTEGER_CST))
return false;
- if (invert1)
- cond1_code = invert_tree_comparison (cond1_code, false);
- if (invert2)
- cond2_code = invert_tree_comparison (cond2_code, false);
-
- cond1_lhs = ((gc1 == GIMPLE_ASSIGN)
- ? gimple_assign_rhs1 (cond1)
- : gimple_cond_lhs (cond1));
- cond1_rhs = ((gc1 == GIMPLE_ASSIGN)
- ? gimple_assign_rhs2 (cond1)
- : gimple_cond_rhs (cond1));
- cond2_lhs = ((gc2 == GIMPLE_ASSIGN)
- ? gimple_assign_rhs1 (cond2)
- : gimple_cond_lhs (cond2));
- cond2_rhs = ((gc2 == GIMPLE_ASSIGN)
- ? gimple_assign_rhs2 (cond2)
- : gimple_cond_rhs (cond2));
-
- /* Assuming const operands have been swapped to the
- rhs at this point of the analysis. */
-
- if (cond1_lhs != cond2_lhs)
+ if (!operand_equal_p (expr1.pred_lhs, expr2.pred_lhs, 0))
return false;
- if (!is_gimple_constant (cond1_rhs)
- || TREE_CODE (cond1_rhs) != INTEGER_CST)
- return (cond1_rhs == cond2_rhs);
-
- if (!is_gimple_constant (cond2_rhs)
- || TREE_CODE (cond2_rhs) != INTEGER_CST)
- return (cond1_rhs == cond2_rhs);
-
- if (cond1_code == EQ_EXPR)
- return is_value_included_in (cond1_rhs,
- cond2_rhs, cond2_code);
- if (cond1_code == NE_EXPR || cond2_code == EQ_EXPR)
- return ((cond2_code == cond1_code)
- && tree_int_cst_equal (cond1_rhs, cond2_rhs));
-
- if (((cond1_code == GE_EXPR || cond1_code == GT_EXPR)
- && (cond2_code == LE_EXPR || cond2_code == LT_EXPR))
- || ((cond1_code == LE_EXPR || cond1_code == LT_EXPR)
- && (cond2_code == GE_EXPR || cond2_code == GT_EXPR)))
- return false;
+ code1 = expr1.cond_code;
+ if (expr1.invert)
+ code1 = invert_tree_comparison (code1, false);
+ code2 = expr2.cond_code;
+ if (expr2.invert)
+ code2 = invert_tree_comparison (code2, false);
- if (cond1_code != GE_EXPR && cond1_code != GT_EXPR
- && cond1_code != LE_EXPR && cond1_code != LT_EXPR)
+ if (code2 == NE_EXPR && code1 == NE_EXPR)
return false;
- if (cond1_code == GT_EXPR)
- {
- cond1_code = GE_EXPR;
- cond1_rhs = fold_binary (PLUS_EXPR, TREE_TYPE (cond1_rhs),
- cond1_rhs,
- fold_convert (TREE_TYPE (cond1_rhs),
- integer_one_node));
- }
- else if (cond1_code == LT_EXPR)
- {
- cond1_code = LE_EXPR;
- cond1_rhs = fold_binary (MINUS_EXPR, TREE_TYPE (cond1_rhs),
- cond1_rhs,
- fold_convert (TREE_TYPE (cond1_rhs),
- integer_one_node));
- }
+ if (code2 == NE_EXPR)
+ return !value_sat_pred_p (expr2.pred_rhs, expr1.pred_rhs, code1);
- if (!cond1_rhs)
- return false;
+ if (code1 == EQ_EXPR)
+ return value_sat_pred_p (expr1.pred_rhs, expr2.pred_rhs, code2);
+
+ if (code1 == code2)
+ return value_sat_pred_p (expr1.pred_rhs, expr2.pred_rhs, code2,
+ code1 == BIT_AND_EXPR);
- gcc_assert (cond1_code == GE_EXPR || cond1_code == LE_EXPR);
-
- if (cond2_code == GE_EXPR || cond2_code == GT_EXPR ||
- cond2_code == LE_EXPR || cond2_code == LT_EXPR)
- return is_value_included_in (cond1_rhs,
- cond2_rhs, cond2_code);
- else if (cond2_code == NE_EXPR)
- return
- (is_value_included_in (cond1_rhs,
- cond2_rhs, cond2_code)
- && !is_value_included_in (cond2_rhs,
- cond1_rhs, cond1_code));
return false;
}
-/* Returns true if the domain of the condition expression
- in COND is a subset of any of the sub-conditions
- of the normalized condtion NORM_COND. INVERT is a flag
- to indicate of the COND needs to be inverted.
- REVERSE is a flag. When it is true, the check is reversed --
- it returns true if COND is a superset of any of the subconditions
- of NORM_COND. */
+/* Returns true if the domain of PRED1 is a subset
+ of that of PRED2. Returns false if it cannot be proved so. */
static bool
-is_subset_of_any (gimple cond, bool invert,
- norm_cond_t norm_cond, bool reverse)
+is_pred_chain_subset_of (pred_chain pred1, pred_chain pred2)
{
- size_t i;
- size_t len = norm_cond->conds.length ();
+ size_t np1, np2, i1, i2;
+
+ np1 = pred1.length ();
+ np2 = pred2.length ();
- for (i = 0; i < len; i++)
+ for (i2 = 0; i2 < np2; i2++)
{
- if (is_gcond_subset_of (cond, invert,
- norm_cond->conds[i],
- false, reverse))
- return true;
+ bool found = false;
+ pred_info info2 = pred2[i2];
+ for (i1 = 0; i1 < np1; i1++)
+ {
+ pred_info info1 = pred1[i1];
+ if (is_pred_expr_subset_of (info1, info2))
+ {
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ return false;
}
- return false;
+ return true;
}
-/* NORM_COND1 and NORM_COND2 are normalized logical/BIT OR
- expressions (formed by following UD chains not control
- dependence chains). The function returns true of domain
- of and expression NORM_COND1 is a subset of NORM_COND2's.
- The implementation is conservative, and it returns false if
- it the inclusion relationship may not hold. */
+/* Returns true if the domain defined by
+ one pred chain ONE_PRED is a subset of the domain
+ of *PREDS. It returns false if ONE_PRED's domain is
+ not a subset of any of the sub-domains of PREDS
+ (corresponding to each individual chains in it), even
+ though it may be still be a subset of whole domain
+ of PREDS which is the union (ORed) of all its subdomains.
+ In other words, the result is conservative. */
static bool
-is_or_set_subset_of (norm_cond_t norm_cond1,
- norm_cond_t norm_cond2)
+is_included_in (pred_chain one_pred, pred_chain_union preds)
{
size_t i;
- size_t len = norm_cond1->conds.length ();
+ size_t n = preds.length ();
- for (i = 0; i < len; i++)
+ for (i = 0; i < n; i++)
{
- if (!is_subset_of_any (norm_cond1->conds[i],
- false, norm_cond2, false))
- return false;
+ if (is_pred_chain_subset_of (one_pred, preds[i]))
+ return true;
}
- return true;
+
+ return false;
}
-/* NORM_COND1 and NORM_COND2 are normalized logical AND
- expressions (formed by following UD chains not control
- dependence chains). The function returns true of domain
- of and expression NORM_COND1 is a subset of NORM_COND2's. */
+/* Compares two predicate sets PREDS1 and PREDS2 and returns
+ true if the domain defined by PREDS1 is a superset
+ of PREDS2's domain. N1 and N2 are array sizes of PREDS1 and
+ PREDS2 respectively. The implementation chooses not to build
+ generic trees (and relying on the folding capability of the
+ compiler), but instead performs brute force comparison of
+ individual predicate chains (won't be a compile time problem
+ as the chains are pretty short). When the function returns
+ false, it does not necessarily mean *PREDS1 is not a superset
+ of *PREDS2, but mean it may not be so since the analysis cannot
+ prove it. In such cases, false warnings may still be
+ emitted. */
static bool
-is_and_set_subset_of (norm_cond_t norm_cond1,
- norm_cond_t norm_cond2)
+is_superset_of (pred_chain_union preds1, pred_chain_union preds2)
{
- size_t i;
- size_t len = norm_cond2->conds.length ();
+ size_t i, n2;
+ pred_chain one_pred_chain = vNULL;
- for (i = 0; i < len; i++)
+ n2 = preds2.length ();
+
+ for (i = 0; i < n2; i++)
{
- if (!is_subset_of_any (norm_cond2->conds[i],
- false, norm_cond1, true))
- return false;
+ one_pred_chain = preds2[i];
+ if (!is_included_in (one_pred_chain, preds1))
+ return false;
}
+
return true;
}
-/* Returns true of the domain if NORM_COND1 is a subset
- of that of NORM_COND2. Returns false if it can not be
- proved to be so. */
+/* Returns true if X1 is the negate of X2. */
-static bool
-is_norm_cond_subset_of (norm_cond_t norm_cond1,
- norm_cond_t norm_cond2)
+static inline bool
+pred_neg_p (pred_info x1, pred_info x2)
{
- size_t i;
- enum tree_code code1, code2;
-
- code1 = norm_cond1->cond_code;
- code2 = norm_cond2->cond_code;
-
- if (code1 == BIT_AND_EXPR)
- {
- /* Both conditions are AND expressions. */
- if (code2 == BIT_AND_EXPR)
- return is_and_set_subset_of (norm_cond1, norm_cond2);
- /* NORM_COND1 is an AND expression, and NORM_COND2 is an OR
- expression. In this case, returns true if any subexpression
- of NORM_COND1 is a subset of any subexpression of NORM_COND2. */
- else if (code2 == BIT_IOR_EXPR)
- {
- size_t len1;
- len1 = norm_cond1->conds.length ();
- for (i = 0; i < len1; i++)
- {
- gimple cond1 = norm_cond1->conds[i];
- if (is_subset_of_any (cond1, false, norm_cond2, false))
- return true;
- }
- return false;
- }
- else
- {
- gcc_assert (code2 == ERROR_MARK);
- gcc_assert (norm_cond2->conds.length () == 1);
- return is_subset_of_any (norm_cond2->conds[0],
- norm_cond2->invert, norm_cond1, true);
- }
- }
- /* NORM_COND1 is an OR expression */
- else if (code1 == BIT_IOR_EXPR)
- {
- if (code2 != code1)
- return false;
+ enum tree_code c1, c2;
+ if (!operand_equal_p (x1.pred_lhs, x2.pred_lhs, 0)
+ || !operand_equal_p (x1.pred_rhs, x2.pred_rhs, 0))
+ return false;
- return is_or_set_subset_of (norm_cond1, norm_cond2);
- }
+ c1 = x1.cond_code;
+ if (x1.invert == x2.invert)
+ c2 = invert_tree_comparison (x2.cond_code, false);
else
- {
- gcc_assert (code1 == ERROR_MARK);
- gcc_assert (norm_cond1->conds.length () == 1);
- /* Conservatively returns false if NORM_COND1 is non-decomposible
- and NORM_COND2 is an AND expression. */
- if (code2 == BIT_AND_EXPR)
- return false;
-
- if (code2 == BIT_IOR_EXPR)
- return is_subset_of_any (norm_cond1->conds[0],
- norm_cond1->invert, norm_cond2, false);
+ c2 = x2.cond_code;
- gcc_assert (code2 == ERROR_MARK);
- gcc_assert (norm_cond2->conds.length () == 1);
- return is_gcond_subset_of (norm_cond1->conds[0],
- norm_cond1->invert,
- norm_cond2->conds[0],
- norm_cond2->invert, false);
- }
+ return c1 == c2;
}
-/* Returns true of the domain of single predicate expression
- EXPR1 is a subset of that of EXPR2. Returns false if it
- can not be proved. */
-
-static bool
-is_pred_expr_subset_of (use_pred_info_t expr1,
- use_pred_info_t expr2)
-{
- gimple cond1, cond2;
- enum tree_code code1, code2;
- struct norm_cond norm_cond1, norm_cond2;
- bool is_subset = false;
+/* 1) ((x IOR y) != 0) AND (x != 0) is equivalent to (x != 0);
+ 2) (X AND Y) OR (!X AND Y) is equivalent to Y;
+ 3) X OR (!X AND Y) is equivalent to (X OR Y);
+ 4) ((x IAND y) != 0) || (x != 0 AND y != 0)) is equivalent to
+ (x != 0 AND y != 0)
+ 5) (X AND Y) OR (!X AND Z) OR (!Y AND Z) is equivalent to
+ (X AND Y) OR Z
- cond1 = expr1->cond;
- cond2 = expr2->cond;
- code1 = gimple_cond_code (cond1);
- code2 = gimple_cond_code (cond2);
+ PREDS is the predicate chains, and N is the number of chains. */
- if (expr1->invert)
- code1 = invert_tree_comparison (code1, false);
- if (expr2->invert)
- code2 = invert_tree_comparison (code2, false);
+/* Helper function to implement rule 1 above. ONE_CHAIN is
+ the AND predication to be simplified. */
- /* Fast path -- match exactly */
- if ((gimple_cond_lhs (cond1) == gimple_cond_lhs (cond2))
- && (gimple_cond_rhs (cond1) == gimple_cond_rhs (cond2))
- && (code1 == code2))
- return true;
+static void
+simplify_pred (pred_chain *one_chain)
+{
+ size_t i, j, n;
+ bool simplified = false;
+ pred_chain s_chain = vNULL;
- /* Normalize conditions. To keep NE_EXPR, do not invert
- with both need inversion. */
- normalize_cond (cond1, &norm_cond1, (expr1->invert));
- normalize_cond (cond2, &norm_cond2, (expr2->invert));
+ n = one_chain->length ();
- is_subset = is_norm_cond_subset_of (&norm_cond1, &norm_cond2);
+ for (i = 0; i < n; i++)
+ {
+ pred_info *a_pred = &(*one_chain)[i];
- /* Free memory */
- norm_cond1.conds.release ();
- norm_cond2.conds.release ();
- return is_subset ;
+ if (!a_pred->pred_lhs)
+ continue;
+ if (!is_neq_zero_form_p (*a_pred))
+ continue;
+
+ gimple *def_stmt = SSA_NAME_DEF_STMT (a_pred->pred_lhs);
+ if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
+ continue;
+ if (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR)
+ {
+ for (j = 0; j < n; j++)
+ {
+ pred_info *b_pred = &(*one_chain)[j];
+
+ if (!b_pred->pred_lhs)
+ continue;
+ if (!is_neq_zero_form_p (*b_pred))
+ continue;
+
+ if (pred_expr_equal_p (*b_pred, gimple_assign_rhs1 (def_stmt))
+ || pred_expr_equal_p (*b_pred, gimple_assign_rhs2 (def_stmt)))
+ {
+ /* Mark a_pred for removal. */
+ a_pred->pred_lhs = NULL;
+ a_pred->pred_rhs = NULL;
+ simplified = true;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!simplified)
+ return;
+
+ for (i = 0; i < n; i++)
+ {
+ pred_info *a_pred = &(*one_chain)[i];
+ if (!a_pred->pred_lhs)
+ continue;
+ s_chain.safe_push (*a_pred);
+ }
+
+ one_chain->release ();
+ *one_chain = s_chain;
}
-/* Returns true if the domain of PRED1 is a subset
- of that of PRED2. Returns false if it can not be proved so. */
+/* The helper function implements the rule 2 for the
+ OR predicate PREDS.
+
+ 2) (X AND Y) OR (!X AND Y) is equivalent to Y. */
static bool
-is_pred_chain_subset_of (vec<use_pred_info_t> pred1,
- vec<use_pred_info_t> pred2)
+simplify_preds_2 (pred_chain_union *preds)
{
- size_t np1, np2, i1, i2;
+ size_t i, j, n;
+ bool simplified = false;
+ pred_chain_union s_preds = vNULL;
- np1 = pred1.length ();
- np2 = pred2.length ();
+ /* (X AND Y) OR (!X AND Y) is equivalent to Y.
+ (X AND Y) OR (X AND !Y) is equivalent to X. */
- for (i2 = 0; i2 < np2; i2++)
+ n = preds->length ();
+ for (i = 0; i < n; i++)
{
- bool found = false;
- use_pred_info_t info2
- = pred2[i2];
- for (i1 = 0; i1 < np1; i1++)
- {
- use_pred_info_t info1
- = pred1[i1];
- if (is_pred_expr_subset_of (info1, info2))
- {
- found = true;
- break;
- }
- }
- if (!found)
- return false;
+ pred_info x, y;
+ pred_chain *a_chain = &(*preds)[i];
+
+ if (a_chain->length () != 2)
+ continue;
+
+ x = (*a_chain)[0];
+ y = (*a_chain)[1];
+
+ for (j = 0; j < n; j++)
+ {
+ pred_chain *b_chain;
+ pred_info x2, y2;
+
+ if (j == i)
+ continue;
+
+ b_chain = &(*preds)[j];
+ if (b_chain->length () != 2)
+ continue;
+
+ x2 = (*b_chain)[0];
+ y2 = (*b_chain)[1];
+
+ if (pred_equal_p (x, x2) && pred_neg_p (y, y2))
+ {
+ /* Kill a_chain. */
+ a_chain->release ();
+ b_chain->release ();
+ b_chain->safe_push (x);
+ simplified = true;
+ break;
+ }
+ if (pred_neg_p (x, x2) && pred_equal_p (y, y2))
+ {
+ /* Kill a_chain. */
+ a_chain->release ();
+ b_chain->release ();
+ b_chain->safe_push (y);
+ simplified = true;
+ break;
+ }
+ }
}
- return true;
+ /* Now clean up the chain. */
+ if (simplified)
+ {
+ for (i = 0; i < n; i++)
+ {
+ if ((*preds)[i].is_empty ())
+ continue;
+ s_preds.safe_push ((*preds)[i]);
+ }
+ preds->release ();
+ (*preds) = s_preds;
+ s_preds = vNULL;
+ }
+
+ return simplified;
}
-/* Returns true if the domain defined by
- one pred chain ONE_PRED is a subset of the domain
- of *PREDS. It returns false if ONE_PRED's domain is
- not a subset of any of the sub-domains of PREDS (
- corresponding to each individual chains in it), even
- though it may be still be a subset of whole domain
- of PREDS which is the union (ORed) of all its subdomains.
- In other words, the result is conservative. */
+/* The helper function implements the rule 2 for the
+ OR predicate PREDS.
+
+ 3) x OR (!x AND y) is equivalent to x OR y. */
static bool
-is_included_in (vec<use_pred_info_t> one_pred,
- vec<use_pred_info_t> *preds,
- size_t n)
+simplify_preds_3 (pred_chain_union *preds)
{
- size_t i;
+ size_t i, j, n;
+ bool simplified = false;
+
+ /* Now iteratively simplify X OR (!X AND Z ..)
+ into X OR (Z ...). */
+
+ n = preds->length ();
+ if (n < 2)
+ return false;
for (i = 0; i < n; i++)
{
- if (is_pred_chain_subset_of (one_pred, preds[i]))
- return true;
- }
+ pred_info x;
+ pred_chain *a_chain = &(*preds)[i];
- return false;
+ if (a_chain->length () != 1)
+ continue;
+
+ x = (*a_chain)[0];
+
+ for (j = 0; j < n; j++)
+ {
+ pred_chain *b_chain;
+ pred_info x2;
+ size_t k;
+
+ if (j == i)
+ continue;
+
+ b_chain = &(*preds)[j];
+ if (b_chain->length () < 2)
+ continue;
+
+ for (k = 0; k < b_chain->length (); k++)
+ {
+ x2 = (*b_chain)[k];
+ if (pred_neg_p (x, x2))
+ {
+ b_chain->unordered_remove (k);
+ simplified = true;
+ break;
+ }
+ }
+ }
+ }
+ return simplified;
}
-/* compares two predicate sets PREDS1 and PREDS2 and returns
- true if the domain defined by PREDS1 is a superset
- of PREDS2's domain. N1 and N2 are array sizes of PREDS1 and
- PREDS2 respectively. The implementation chooses not to build
- generic trees (and relying on the folding capability of the
- compiler), but instead performs brute force comparison of
- individual predicate chains (won't be a compile time problem
- as the chains are pretty short). When the function returns
- false, it does not necessarily mean *PREDS1 is not a superset
- of *PREDS2, but mean it may not be so since the analysis can
- not prove it. In such cases, false warnings may still be
- emitted. */
+/* The helper function implements the rule 4 for the
+ OR predicate PREDS.
+
+ 2) ((x AND y) != 0) OR (x != 0 AND y != 0) is equivalent to
+ (x != 0 ANd y != 0). */
static bool
-is_superset_of (vec<use_pred_info_t> *preds1,
- size_t n1,
- vec<use_pred_info_t> *preds2,
- size_t n2)
+simplify_preds_4 (pred_chain_union *preds)
{
- size_t i;
- vec<use_pred_info_t> one_pred_chain;
+ size_t i, j, n;
+ bool simplified = false;
+ pred_chain_union s_preds = vNULL;
+ gimple *def_stmt;
- for (i = 0; i < n2; i++)
+ n = preds->length ();
+ for (i = 0; i < n; i++)
{
- one_pred_chain = preds2[i];
- if (!is_included_in (one_pred_chain, preds1, n1))
- return false;
+ pred_info z;
+ pred_chain *a_chain = &(*preds)[i];
+
+ if (a_chain->length () != 1)
+ continue;
+
+ z = (*a_chain)[0];
+
+ if (!is_neq_zero_form_p (z))
+ continue;
+
+ def_stmt = SSA_NAME_DEF_STMT (z.pred_lhs);
+ if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
+ continue;
+
+ if (gimple_assign_rhs_code (def_stmt) != BIT_AND_EXPR)
+ continue;
+
+ for (j = 0; j < n; j++)
+ {
+ pred_chain *b_chain;
+ pred_info x2, y2;
+
+ if (j == i)
+ continue;
+
+ b_chain = &(*preds)[j];
+ if (b_chain->length () != 2)
+ continue;
+
+ x2 = (*b_chain)[0];
+ y2 = (*b_chain)[1];
+ if (!is_neq_zero_form_p (x2) || !is_neq_zero_form_p (y2))
+ continue;
+
+ if ((pred_expr_equal_p (x2, gimple_assign_rhs1 (def_stmt))
+ && pred_expr_equal_p (y2, gimple_assign_rhs2 (def_stmt)))
+ || (pred_expr_equal_p (x2, gimple_assign_rhs2 (def_stmt))
+ && pred_expr_equal_p (y2, gimple_assign_rhs1 (def_stmt))))
+ {
+ /* Kill a_chain. */
+ a_chain->release ();
+ simplified = true;
+ break;
+ }
+ }
}
+ /* Now clean up the chain. */
+ if (simplified)
+ {
+ for (i = 0; i < n; i++)
+ {
+ if ((*preds)[i].is_empty ())
+ continue;
+ s_preds.safe_push ((*preds)[i]);
+ }
- return true;
+ preds->release ();
+ (*preds) = s_preds;
+ s_preds = vNULL;
+ }
+
+ return simplified;
}
-/* Comparison function used by qsort. It is used to
- sort predicate chains to allow predicate
- simplification. */
+/* This function simplifies predicates in PREDS. */
-static int
-pred_chain_length_cmp (const void *p1, const void *p2)
+static void
+simplify_preds (pred_chain_union *preds, gimple *use_or_def, bool is_use)
{
- use_pred_info_t i1, i2;
- vec<use_pred_info_t> const *chain1
- = (vec<use_pred_info_t> const *)p1;
- vec<use_pred_info_t> const *chain2
- = (vec<use_pred_info_t> const *)p2;
+ size_t i, n;
+ bool changed = false;
+
+ if (dump_file && dump_flags & TDF_DETAILS)
+ {
+ fprintf (dump_file, "[BEFORE SIMPLICATION -- ");
+ dump_predicates (use_or_def, *preds, is_use ? "[USE]:\n" : "[DEF]:\n");
+ }
- if (chain1->length () != chain2->length ())
- return (chain1->length () - chain2->length ());
+ for (i = 0; i < preds->length (); i++)
+ simplify_pred (&(*preds)[i]);
- i1 = (*chain1)[0];
- i2 = (*chain2)[0];
+ n = preds->length ();
+ if (n < 2)
+ return;
- /* Allow predicates with similar prefix come together. */
- if (!i1->invert && i2->invert)
- return -1;
- else if (i1->invert && !i2->invert)
- return 1;
+ do
+ {
+ changed = false;
+ if (simplify_preds_2 (preds))
+ changed = true;
+
+ /* Now iteratively simplify X OR (!X AND Z ..)
+ into X OR (Z ...). */
+ if (simplify_preds_3 (preds))
+ changed = true;
+
+ if (simplify_preds_4 (preds))
+ changed = true;
+ }
+ while (changed);
+
+ return;
+}
+
+/* This is a helper function which attempts to normalize predicate chains
+ by following UD chains. It basically builds up a big tree of either IOR
+ operations or AND operations, and convert the IOR tree into a
+ pred_chain_union or BIT_AND tree into a pred_chain.
+ Example:
+
+ _3 = _2 RELOP1 _1;
+ _6 = _5 RELOP2 _4;
+ _9 = _8 RELOP3 _7;
+ _10 = _3 | _6;
+ _12 = _9 | _0;
+ _t = _10 | _12;
+
+ then _t != 0 will be normalized into a pred_chain_union
+
+ (_2 RELOP1 _1) OR (_5 RELOP2 _4) OR (_8 RELOP3 _7) OR (_0 != 0)
+
+ Similarly given,
+
+ _3 = _2 RELOP1 _1;
+ _6 = _5 RELOP2 _4;
+ _9 = _8 RELOP3 _7;
+ _10 = _3 & _6;
+ _12 = _9 & _0;
- return gimple_uid (i1->cond) - gimple_uid (i2->cond);
+ then _t != 0 will be normalized into a pred_chain:
+ (_2 RELOP1 _1) AND (_5 RELOP2 _4) AND (_8 RELOP3 _7) AND (_0 != 0)
+
+ */
+
+/* This is a helper function that stores a PRED into NORM_PREDS. */
+
+inline static void
+push_pred (pred_chain_union *norm_preds, pred_info pred)
+{
+ pred_chain pred_chain = vNULL;
+ pred_chain.safe_push (pred);
+ norm_preds->safe_push (pred_chain);
}
-/* x OR (!x AND y) is equivalent to x OR y.
- This function normalizes x1 OR (!x1 AND x2) OR (!x1 AND !x2 AND x3)
- into x1 OR x2 OR x3. PREDS is the predicate chains, and N is
- the number of chains. Returns true if normalization happens. */
+/* A helper function that creates a predicate of the form
+ OP != 0 and push it WORK_LIST. */
+
+inline static void
+push_to_worklist (tree op, vec<pred_info, va_heap, vl_ptr> *work_list,
+ hash_set<tree> *mark_set)
+{
+ if (mark_set->contains (op))
+ return;
+ mark_set->add (op);
+
+ pred_info arg_pred;
+ arg_pred.pred_lhs = op;
+ arg_pred.pred_rhs = integer_zero_node;
+ arg_pred.cond_code = NE_EXPR;
+ arg_pred.invert = false;
+ work_list->safe_push (arg_pred);
+}
+
+/* A helper that generates a pred_info from a gimple assignment
+ CMP_ASSIGN with comparison rhs. */
+
+static pred_info
+get_pred_info_from_cmp (gimple *cmp_assign)
+{
+ pred_info n_pred;
+ n_pred.pred_lhs = gimple_assign_rhs1 (cmp_assign);
+ n_pred.pred_rhs = gimple_assign_rhs2 (cmp_assign);
+ n_pred.cond_code = gimple_assign_rhs_code (cmp_assign);
+ n_pred.invert = false;
+ return n_pred;
+}
+
+/* Returns true if the PHI is a degenerated phi with
+ all args with the same value (relop). In that case, *PRED
+ will be updated to that value. */
static bool
-normalize_preds (vec<use_pred_info_t> *preds, size_t *n)
+is_degenerated_phi (gimple *phi, pred_info *pred_p)
{
- size_t i, j, ll;
- vec<use_pred_info_t> pred_chain;
- vec<use_pred_info_t> x = vNULL;
- use_pred_info_t xj = 0, nxj = 0;
+ int i, n;
+ tree op0;
+ gimple *def0;
+ pred_info pred0;
+
+ n = gimple_phi_num_args (phi);
+ op0 = gimple_phi_arg_def (phi, 0);
- if (*n < 2)
+ if (TREE_CODE (op0) != SSA_NAME)
return false;
- /* First sort the chains in ascending order of lengths. */
- qsort (preds, *n, sizeof (void *), pred_chain_length_cmp);
- pred_chain = preds[0];
- ll = pred_chain.length ();
- if (ll != 1)
- {
- if (ll == 2)
- {
- use_pred_info_t xx, yy, xx2, nyy;
- vec<use_pred_info_t> pred_chain2 = preds[1];
- if (pred_chain2.length () != 2)
- return false;
-
- /* See if simplification x AND y OR x AND !y is possible. */
- xx = pred_chain[0];
- yy = pred_chain[1];
- xx2 = pred_chain2[0];
- nyy = pred_chain2[1];
- if (gimple_cond_lhs (xx->cond) != gimple_cond_lhs (xx2->cond)
- || gimple_cond_rhs (xx->cond) != gimple_cond_rhs (xx2->cond)
- || gimple_cond_code (xx->cond) != gimple_cond_code (xx2->cond)
- || (xx->invert != xx2->invert))
- return false;
- if (gimple_cond_lhs (yy->cond) != gimple_cond_lhs (nyy->cond)
- || gimple_cond_rhs (yy->cond) != gimple_cond_rhs (nyy->cond)
- || gimple_cond_code (yy->cond) != gimple_cond_code (nyy->cond)
- || (yy->invert == nyy->invert))
- return false;
-
- /* Now merge the first two chains. */
- free (yy);
- free (nyy);
- free (xx2);
- pred_chain.release ();
- pred_chain2.release ();
- pred_chain.safe_push (xx);
- preds[0] = pred_chain;
- for (i = 1; i < *n - 1; i++)
- preds[i] = preds[i + 1];
-
- preds[*n - 1].create (0);
- *n = *n - 1;
- }
- else
- return false;
- }
+ def0 = SSA_NAME_DEF_STMT (op0);
+ if (gimple_code (def0) != GIMPLE_ASSIGN)
+ return false;
+ if (TREE_CODE_CLASS (gimple_assign_rhs_code (def0)) != tcc_comparison)
+ return false;
+ pred0 = get_pred_info_from_cmp (def0);
+
+ for (i = 1; i < n; ++i)
+ {
+ gimple *def;
+ pred_info pred;
+ tree op = gimple_phi_arg_def (phi, i);
+
+ if (TREE_CODE (op) != SSA_NAME)
+ return false;
+
+ def = SSA_NAME_DEF_STMT (op);
+ if (gimple_code (def) != GIMPLE_ASSIGN)
+ return false;
+ if (TREE_CODE_CLASS (gimple_assign_rhs_code (def)) != tcc_comparison)
+ return false;
+ pred = get_pred_info_from_cmp (def);
+ if (!pred_equal_p (pred, pred0))
+ return false;
+ }
+
+ *pred_p = pred0;
+ return true;
+}
+
+/* Normalize one predicate PRED
+ 1) if PRED can no longer be normlized, put it into NORM_PREDS.
+ 2) otherwise if PRED is of the form x != 0, follow x's definition
+ and put normalized predicates into WORK_LIST. */
+
+static void
+normalize_one_pred_1 (pred_chain_union *norm_preds,
+ pred_chain *norm_chain,
+ pred_info pred,
+ enum tree_code and_or_code,
+ vec<pred_info, va_heap, vl_ptr> *work_list,
+ hash_set<tree> *mark_set)
+{
+ if (!is_neq_zero_form_p (pred))
+ {
+ if (and_or_code == BIT_IOR_EXPR)
+ push_pred (norm_preds, pred);
+ else
+ norm_chain->safe_push (pred);
+ return;
+ }
+
+ gimple *def_stmt = SSA_NAME_DEF_STMT (pred.pred_lhs);
+
+ if (gimple_code (def_stmt) == GIMPLE_PHI
+ && is_degenerated_phi (def_stmt, &pred))
+ work_list->safe_push (pred);
+ else if (gimple_code (def_stmt) == GIMPLE_PHI && and_or_code == BIT_IOR_EXPR)
+ {
+ int i, n;
+ n = gimple_phi_num_args (def_stmt);
+
+ /* If we see non zero constant, we should punt. The predicate
+ * should be one guarding the phi edge. */
+ for (i = 0; i < n; ++i)
+ {
+ tree op = gimple_phi_arg_def (def_stmt, i);
+ if (TREE_CODE (op) == INTEGER_CST && !integer_zerop (op))
+ {
+ push_pred (norm_preds, pred);
+ return;
+ }
+ }
+
+ for (i = 0; i < n; ++i)
+ {
+ tree op = gimple_phi_arg_def (def_stmt, i);
+ if (integer_zerop (op))
+ continue;
+
+ push_to_worklist (op, work_list, mark_set);
+ }
+ }
+ else if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
+ {
+ if (and_or_code == BIT_IOR_EXPR)
+ push_pred (norm_preds, pred);
+ else
+ norm_chain->safe_push (pred);
+ }
+ else if (gimple_assign_rhs_code (def_stmt) == and_or_code)
+ {
+ /* Avoid splitting up bit manipulations like x & 3 or y | 1. */
+ if (is_gimple_min_invariant (gimple_assign_rhs2 (def_stmt)))
+ {
+ /* But treat x & 3 as condition. */
+ if (and_or_code == BIT_AND_EXPR)
+ {
+ pred_info n_pred;
+ n_pred.pred_lhs = gimple_assign_rhs1 (def_stmt);
+ n_pred.pred_rhs = gimple_assign_rhs2 (def_stmt);
+ n_pred.cond_code = and_or_code;
+ n_pred.invert = false;
+ norm_chain->safe_push (n_pred);
+ }
+ }
+ else
+ {
+ push_to_worklist (gimple_assign_rhs1 (def_stmt), work_list, mark_set);
+ push_to_worklist (gimple_assign_rhs2 (def_stmt), work_list, mark_set);
+ }
+ }
+ else if (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt))
+ == tcc_comparison)
+ {
+ pred_info n_pred = get_pred_info_from_cmp (def_stmt);
+ if (and_or_code == BIT_IOR_EXPR)
+ push_pred (norm_preds, n_pred);
+ else
+ norm_chain->safe_push (n_pred);
+ }
+ else
+ {
+ if (and_or_code == BIT_IOR_EXPR)
+ push_pred (norm_preds, pred);
+ else
+ norm_chain->safe_push (pred);
+ }
+}
+
+/* Normalize PRED and store the normalized predicates into NORM_PREDS. */
+
+static void
+normalize_one_pred (pred_chain_union *norm_preds, pred_info pred)
+{
+ vec<pred_info, va_heap, vl_ptr> work_list = vNULL;
+ enum tree_code and_or_code = ERROR_MARK;
+ pred_chain norm_chain = vNULL;
+
+ if (!is_neq_zero_form_p (pred))
+ {
+ push_pred (norm_preds, pred);
+ return;
+ }
+
+ gimple *def_stmt = SSA_NAME_DEF_STMT (pred.pred_lhs);
+ if (gimple_code (def_stmt) == GIMPLE_ASSIGN)
+ and_or_code = gimple_assign_rhs_code (def_stmt);
+ if (and_or_code != BIT_IOR_EXPR && and_or_code != BIT_AND_EXPR)
+ {
+ if (TREE_CODE_CLASS (and_or_code) == tcc_comparison)
+ {
+ pred_info n_pred = get_pred_info_from_cmp (def_stmt);
+ push_pred (norm_preds, n_pred);
+ }
+ else
+ push_pred (norm_preds, pred);
+ return;
+ }
+
+ work_list.safe_push (pred);
+ hash_set<tree> mark_set;
+
+ while (!work_list.is_empty ())
+ {
+ pred_info a_pred = work_list.pop ();
+ normalize_one_pred_1 (norm_preds, &norm_chain, a_pred, and_or_code,
+ &work_list, &mark_set);
+ }
+ if (and_or_code == BIT_AND_EXPR)
+ norm_preds->safe_push (norm_chain);
+
+ work_list.release ();
+}
+
+static void
+normalize_one_pred_chain (pred_chain_union *norm_preds, pred_chain one_chain)
+{
+ vec<pred_info, va_heap, vl_ptr> work_list = vNULL;
+ hash_set<tree> mark_set;
+ pred_chain norm_chain = vNULL;
+ size_t i;
- x.safe_push (pred_chain[0]);
+ for (i = 0; i < one_chain.length (); i++)
+ {
+ work_list.safe_push (one_chain[i]);
+ mark_set.add (one_chain[i].pred_lhs);
+ }
- /* The loop extracts x1, x2, x3, etc from chains
- x1 OR (!x1 AND x2) OR (!x1 AND !x2 AND x3) OR ... */
- for (i = 1; i < *n; i++)
+ while (!work_list.is_empty ())
{
- pred_chain = preds[i];
- if (pred_chain.length () != i + 1)
- return false;
+ pred_info a_pred = work_list.pop ();
+ normalize_one_pred_1 (0, &norm_chain, a_pred, BIT_AND_EXPR, &work_list,
+ &mark_set);
+ }
- for (j = 0; j < i; j++)
- {
- xj = x[j];
- nxj = pred_chain[j];
+ norm_preds->safe_push (norm_chain);
+ work_list.release ();
+}
- /* Check if nxj is !xj */
- if (gimple_cond_lhs (xj->cond) != gimple_cond_lhs (nxj->cond)
- || gimple_cond_rhs (xj->cond) != gimple_cond_rhs (nxj->cond)
- || gimple_cond_code (xj->cond) != gimple_cond_code (nxj->cond)
- || (xj->invert == nxj->invert))
- return false;
- }
+/* Normalize predicate chains PREDS and returns the normalized one. */
+
+static pred_chain_union
+normalize_preds (pred_chain_union preds, gimple *use_or_def, bool is_use)
+{
+ pred_chain_union norm_preds = vNULL;
+ size_t n = preds.length ();
+ size_t i;
- x.safe_push (pred_chain[i]);
+ if (dump_file && dump_flags & TDF_DETAILS)
+ {
+ fprintf (dump_file, "[BEFORE NORMALIZATION --");
+ dump_predicates (use_or_def, preds, is_use ? "[USE]:\n" : "[DEF]:\n");
}
- /* Now normalize the pred chains using the extraced x1, x2, x3 etc. */
- for (j = 0; j < *n; j++)
+ for (i = 0; i < n; i++)
{
- use_pred_info_t t;
- xj = x[j];
+ if (preds[i].length () != 1)
+ normalize_one_pred_chain (&norm_preds, preds[i]);
+ else
+ {
+ normalize_one_pred (&norm_preds, preds[i][0]);
+ preds[i].release ();
+ }
+ }
- t = XNEW (struct use_pred_info);
- *t = *xj;
+ if (dump_file)
+ {
+ fprintf (dump_file, "[AFTER NORMALIZATION -- ");
+ dump_predicates (use_or_def, norm_preds,
+ is_use ? "[USE]:\n" : "[DEF]:\n");
+ }
+
+ destroy_predicate_vecs (&preds);
+ return norm_preds;
+}
+
+/* Return TRUE if PREDICATE can be invalidated by any individual
+ predicate in USE_GUARD. */
- x[j] = t;
+static bool
+can_one_predicate_be_invalidated_p (pred_info predicate,
+ pred_chain use_guard)
+{
+ if (dump_file && dump_flags & TDF_DETAILS)
+ {
+ fprintf (dump_file, "Testing if this predicate: ");
+ dump_pred_info (predicate);
+ fprintf (dump_file, "\n...can be invalidated by a USE guard of: ");
+ dump_pred_chain (use_guard);
}
+ for (size_t i = 0; i < use_guard.length (); ++i)
+ {
+ /* NOTE: This is a very simple check, and only understands an
+ exact opposite. So, [i == 0] is currently only invalidated
+ by [.NOT. i == 0] or [i != 0]. Ideally we should also
+ invalidate with say [i > 5] or [i == 8]. There is certainly
+ room for improvement here. */
+ if (pred_neg_p (predicate, use_guard[i]))
+ {
+ if (dump_file && dump_flags & TDF_DETAILS)
+ {
+ fprintf (dump_file, " Predicate was invalidated by: ");
+ dump_pred_info (use_guard[i]);
+ fputc ('\n', dump_file);
+ }
+ return true;
+ }
+ }
+ return false;
+}
+
+/* Return TRUE if all predicates in UNINIT_PRED are invalidated by
+ USE_GUARD being true. */
- for (i = 0; i < *n; i++)
+static bool
+can_chain_union_be_invalidated_p (pred_chain_union uninit_pred,
+ pred_chain use_guard)
+{
+ if (uninit_pred.is_empty ())
+ return false;
+ if (dump_file && dump_flags & TDF_DETAILS)
+ dump_predicates (NULL, uninit_pred,
+ "Testing if anything here can be invalidated: ");
+ for (size_t i = 0; i < uninit_pred.length (); ++i)
{
- pred_chain = preds[i];
- for (j = 0; j < pred_chain.length (); j++)
- free (pred_chain[j]);
- pred_chain.release ();
- /* A new chain. */
- pred_chain.safe_push (x[i]);
- preds[i] = pred_chain;
+ pred_chain c = uninit_pred[i];
+ size_t j;
+ for (j = 0; j < c.length (); ++j)
+ if (can_one_predicate_be_invalidated_p (c[j], use_guard))
+ break;
+
+ /* If we were unable to invalidate any predicate in C, then there
+ is a viable path from entry to the PHI where the PHI takes
+ an uninitialized value and continues to a use of the PHI. */
+ if (j == c.length ())
+ return false;
}
return true;
}
+/* Return TRUE if none of the uninitialized operands in UNINT_OPNDS
+ can actually happen if we arrived at a use for PHI.
+
+ PHI_USE_GUARDS are the guard conditions for the use of the PHI. */
+
+static bool
+uninit_uses_cannot_happen (gphi *phi, unsigned uninit_opnds,
+ pred_chain_union phi_use_guards)
+{
+ unsigned phi_args = gimple_phi_num_args (phi);
+ if (phi_args > max_phi_args)
+ return false;
+
+ /* PHI_USE_GUARDS are OR'ed together. If we have more than one
+ possible guard, there's no way of knowing which guard was true.
+ Since we need to be absolutely sure that the uninitialized
+ operands will be invalidated, bail. */
+ if (phi_use_guards.length () != 1)
+ return false;
+
+ /* Look for the control dependencies of all the uninitialized
+ operands and build guard predicates describing them. */
+ pred_chain_union uninit_preds;
+ bool ret = true;
+ for (unsigned i = 0; i < phi_args; ++i)
+ {
+ if (!MASK_TEST_BIT (uninit_opnds, i))
+ continue;
+
+ edge e = gimple_phi_arg_edge (phi, i);
+ vec<edge> dep_chains[MAX_NUM_CHAINS];
+ auto_vec<edge, MAX_CHAIN_LEN + 1> cur_chain;
+ size_t num_chains = 0;
+ int num_calls = 0;
+
+ /* Build the control dependency chain for uninit operand `i'... */
+ uninit_preds = vNULL;
+ if (!compute_control_dep_chain (ENTRY_BLOCK_PTR_FOR_FN (cfun),
+ e->src, dep_chains, &num_chains,
+ &cur_chain, &num_calls))
+ {
+ ret = false;
+ break;
+ }
+ /* ...and convert it into a set of predicates. */
+ bool has_valid_preds
+ = convert_control_dep_chain_into_preds (dep_chains, num_chains,
+ &uninit_preds);
+ for (size_t j = 0; j < num_chains; ++j)
+ dep_chains[j].release ();
+ if (!has_valid_preds)
+ {
+ ret = false;
+ break;
+ }
+ simplify_preds (&uninit_preds, NULL, false);
+ uninit_preds = normalize_preds (uninit_preds, NULL, false);
+ /* Can the guard for this uninitialized operand be invalidated
+ by the PHI use? */
+ if (!can_chain_union_be_invalidated_p (uninit_preds, phi_use_guards[0]))
+ {
+ ret = false;
+ break;
+ }
+ }
+ destroy_predicate_vecs (&uninit_preds);
+ return ret;
+}
/* Computes the predicates that guard the use and checks
if the incoming paths that have empty (or possibly
- empty) definition can be pruned/filtered. The function returns
+ empty) definition can be pruned/filtered. The function returns
true if it can be determined that the use of PHI's def in
USE_STMT is guarded with a predicate set not overlapping with
predicate sets of all runtime paths that do not have a definition.
- Returns false if it is not or it can not be determined. USE_BB is
+
+ Returns false if it is not or it cannot be determined. USE_BB is
the bb of the use (for phi operand use, the bb is not the bb of
- the phi stmt, but the src bb of the operand edge). UNINIT_OPNDS
- is a bit vector. If an operand of PHI is uninitialized, the
- corresponding bit in the vector is 1. VISIED_PHIS is a pointer
- set of phis being visted. */
+ the phi stmt, but the src bb of the operand edge).
+
+ UNINIT_OPNDS is a bit vector. If an operand of PHI is uninitialized, the
+ corresponding bit in the vector is 1. VISITED_PHIS is a pointer
+ set of phis being visited.
+
+ *DEF_PREDS contains the (memoized) defining predicate chains of PHI.
+ If *DEF_PREDS is the empty vector, the defining predicate chains of
+ PHI will be computed and stored into *DEF_PREDS as needed.
+
+ VISITED_PHIS is a pointer set of phis being visited. */
static bool
-is_use_properly_guarded (gimple use_stmt,
- basic_block use_bb,
- gimple phi,
- unsigned uninit_opnds,
- struct pointer_set_t *visited_phis)
+is_use_properly_guarded (gimple *use_stmt,
+ basic_block use_bb,
+ gphi *phi,
+ unsigned uninit_opnds,
+ pred_chain_union *def_preds,
+ hash_set<gphi *> *visited_phis)
{
basic_block phi_bb;
- vec<use_pred_info_t> *preds = 0;
- vec<use_pred_info_t> *def_preds = 0;
- size_t num_preds = 0, num_def_preds = 0;
+ pred_chain_union preds = vNULL;
bool has_valid_preds = false;
bool is_properly_guarded = false;
- if (pointer_set_insert (visited_phis, phi))
+ if (visited_phis->add (phi))
return false;
phi_bb = gimple_bb (phi);
if (is_non_loop_exit_postdominating (use_bb, phi_bb))
return false;
- has_valid_preds = find_predicates (&preds, &num_preds,
- phi_bb, use_bb);
+ has_valid_preds = find_predicates (&preds, phi_bb, use_bb);
if (!has_valid_preds)
{
- destroy_predicate_vecs (num_preds, preds);
+ destroy_predicate_vecs (&preds);
return false;
}
- if (dump_file)
- dump_predicates (use_stmt, num_preds, preds,
- "\nUse in stmt ");
+ /* Try to prune the dead incoming phi edges. */
+ is_properly_guarded
+ = use_pred_not_overlap_with_undef_path_pred (preds, phi, uninit_opnds,
+ visited_phis);
- has_valid_preds = find_def_preds (&def_preds,
- &num_def_preds, phi);
+ /* We might be able to prove that if the control dependencies
+ for UNINIT_OPNDS are true, that the control dependencies for
+ USE_STMT can never be true. */
+ if (!is_properly_guarded)
+ is_properly_guarded |= uninit_uses_cannot_happen (phi, uninit_opnds,
+ preds);
- if (has_valid_preds)
+ if (is_properly_guarded)
{
- bool normed;
- if (dump_file)
- dump_predicates (phi, num_def_preds, def_preds,
- "Operand defs of phi ");
+ destroy_predicate_vecs (&preds);
+ return true;
+ }
- normed = normalize_preds (def_preds, &num_def_preds);
- if (normed && dump_file)
- {
- fprintf (dump_file, "\nNormalized to\n");
- dump_predicates (phi, num_def_preds, def_preds,
- "Operand defs of phi ");
- }
- is_properly_guarded =
- is_superset_of (def_preds, num_def_preds,
- preds, num_preds);
+ if (def_preds->is_empty ())
+ {
+ has_valid_preds = find_def_preds (def_preds, phi);
+
+ if (!has_valid_preds)
+ {
+ destroy_predicate_vecs (&preds);
+ return false;
+ }
+
+ simplify_preds (def_preds, phi, false);
+ *def_preds = normalize_preds (*def_preds, phi, false);
}
- /* further prune the dead incoming phi edges. */
- if (!is_properly_guarded)
- is_properly_guarded
- = use_pred_not_overlap_with_undef_path_pred (
- num_preds, preds, phi, uninit_opnds, visited_phis);
+ simplify_preds (&preds, use_stmt, true);
+ preds = normalize_preds (preds, use_stmt, true);
+
+ is_properly_guarded = is_superset_of (*def_preds, preds);
- destroy_predicate_vecs (num_preds, preds);
- destroy_predicate_vecs (num_def_preds, def_preds);
+ destroy_predicate_vecs (&preds);
return is_properly_guarded;
}
/* Searches through all uses of a potentially
uninitialized variable defined by PHI and returns a use
- statement if the use is not properly guarded. It returns
- NULL if all uses are guarded. UNINIT_OPNDS is a bitvector
- holding the position(s) of uninit PHI operands. WORKLIST
+ statement if the use is not properly guarded. It returns
+ NULL if all uses are guarded. UNINIT_OPNDS is a bitvector
+ holding the position(s) of uninit PHI operands. WORKLIST
is the vector of candidate phis that may be updated by this
- function. ADDED_TO_WORKLIST is the pointer set tracking
+ function. ADDED_TO_WORKLIST is the pointer set tracking
if the new phi is already in the worklist. */
-static gimple
-find_uninit_use (gimple phi, unsigned uninit_opnds,
- vec<gimple> *worklist,
- struct pointer_set_t *added_to_worklist)
+static gimple *
+find_uninit_use (gphi *phi, unsigned uninit_opnds,
+ vec<gphi *> *worklist,
+ hash_set<gphi *> *added_to_worklist)
{
tree phi_result;
use_operand_p use_p;
- gimple use_stmt;
+ gimple *use_stmt;
imm_use_iterator iter;
+ pred_chain_union def_preds = vNULL;
+ gimple *ret = NULL;
phi_result = gimple_phi_result (phi);
FOR_EACH_IMM_USE_FAST (use_p, iter, phi_result)
{
- struct pointer_set_t *visited_phis;
basic_block use_bb;
use_stmt = USE_STMT (use_p);
if (is_gimple_debug (use_stmt))
continue;
- visited_phis = pointer_set_create ();
-
- if (gimple_code (use_stmt) == GIMPLE_PHI)
- use_bb = gimple_phi_arg_edge (use_stmt,
+ if (gphi *use_phi = dyn_cast<gphi *> (use_stmt))
+ use_bb = gimple_phi_arg_edge (use_phi,
PHI_ARG_INDEX_FROM_USE (use_p))->src;
else
use_bb = gimple_bb (use_stmt);
- if (is_use_properly_guarded (use_stmt,
- use_bb,
- phi,
- uninit_opnds,
- visited_phis))
- {
- pointer_set_destroy (visited_phis);
- continue;
- }
- pointer_set_destroy (visited_phis);
+ hash_set<gphi *> visited_phis;
+ if (is_use_properly_guarded (use_stmt, use_bb, phi, uninit_opnds,
+ &def_preds, &visited_phis))
+ continue;
if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[CHECK]: Found unguarded use: ");
- print_gimple_stmt (dump_file, use_stmt, 0, 0);
- }
+ {
+ fprintf (dump_file, "[CHECK]: Found unguarded use: ");
+ print_gimple_stmt (dump_file, use_stmt, 0);
+ }
/* Found one real use, return. */
if (gimple_code (use_stmt) != GIMPLE_PHI)
- return use_stmt;
+ {
+ ret = use_stmt;
+ break;
+ }
/* Found a phi use that is not guarded,
- add the phi to the worklist. */
- if (!pointer_set_insert (added_to_worklist,
- use_stmt))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[WORKLIST]: Update worklist with phi: ");
- print_gimple_stmt (dump_file, use_stmt, 0, 0);
- }
+ add the phi to the worklist. */
+ if (!added_to_worklist->add (as_a<gphi *> (use_stmt)))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "[WORKLIST]: Update worklist with phi: ");
+ print_gimple_stmt (dump_file, use_stmt, 0);
+ }
- worklist->safe_push (use_stmt);
- pointer_set_insert (possibly_undefined_names, phi_result);
- }
+ worklist->safe_push (as_a<gphi *> (use_stmt));
+ possibly_undefined_names->add (phi_result);
+ }
}
- return NULL;
+ destroy_predicate_vecs (&def_preds);
+ return ret;
}
/* Look for inputs to PHI that are SSA_NAMEs that have empty definitions
and gives warning if there exists a runtime path from the entry to a
- use of the PHI def that does not contain a definition. In other words,
- the warning is on the real use. The more dead paths that can be pruned
- by the compiler, the fewer false positives the warning is. WORKLIST
- is a vector of candidate phis to be examined. ADDED_TO_WORKLIST is
+ use of the PHI def that does not contain a definition. In other words,
+ the warning is on the real use. The more dead paths that can be pruned
+ by the compiler, the fewer false positives the warning is. WORKLIST
+ is a vector of candidate phis to be examined. ADDED_TO_WORKLIST is
a pointer set tracking if the new phi is added to the worklist or not. */
static void
-warn_uninitialized_phi (gimple phi, vec<gimple> *worklist,
- struct pointer_set_t *added_to_worklist)
+warn_uninitialized_phi (gphi *phi, vec<gphi *> *worklist,
+ hash_set<gphi *> *added_to_worklist)
{
unsigned uninit_opnds;
- gimple uninit_use_stmt = 0;
+ gimple *uninit_use_stmt = 0;
tree uninit_op;
+ int phiarg_index;
+ location_t loc;
/* Don't look at virtual operands. */
if (virtual_operand_p (gimple_phi_result (phi)))
uninit_opnds = compute_uninit_opnds_pos (phi);
- if (MASK_EMPTY (uninit_opnds))
+ if (MASK_EMPTY (uninit_opnds))
return;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "[CHECK]: examining phi: ");
- print_gimple_stmt (dump_file, phi, 0, 0);
+ print_gimple_stmt (dump_file, phi, 0);
}
/* Now check if we have any use of the value without proper guard. */
uninit_use_stmt = find_uninit_use (phi, uninit_opnds,
- worklist, added_to_worklist);
+ worklist, added_to_worklist);
/* All uses are properly guarded. */
if (!uninit_use_stmt)
return;
- uninit_op = gimple_phi_arg_def (phi, MASK_FIRST_SET_BIT (uninit_opnds));
+ phiarg_index = MASK_FIRST_SET_BIT (uninit_opnds);
+ uninit_op = gimple_phi_arg_def (phi, phiarg_index);
if (SSA_NAME_VAR (uninit_op) == NULL_TREE)
return;
+ if (gimple_phi_arg_has_location (phi, phiarg_index))
+ loc = gimple_phi_arg_location (phi, phiarg_index);
+ else
+ loc = UNKNOWN_LOCATION;
warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, SSA_NAME_VAR (uninit_op),
SSA_NAME_VAR (uninit_op),
- "%qD may be used uninitialized in this function",
- uninit_use_stmt);
+ "%qD may be used uninitialized in this function",
+ uninit_use_stmt, loc);
+}
+static bool
+gate_warn_uninitialized (void)
+{
+ return warn_uninitialized || warn_maybe_uninitialized;
}
+namespace {
-/* Entry point to the late uninitialized warning pass. */
+const pass_data pass_data_late_warn_uninitialized =
+{
+ GIMPLE_PASS, /* type */
+ "uninit", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_NONE, /* tv_id */
+ PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+};
-static unsigned int
-execute_late_warn_uninitialized (void)
+class pass_late_warn_uninitialized : public gimple_opt_pass
+{
+public:
+ pass_late_warn_uninitialized (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_late_warn_uninitialized, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ opt_pass *clone () { return new pass_late_warn_uninitialized (m_ctxt); }
+ virtual bool gate (function *) { return gate_warn_uninitialized (); }
+ virtual unsigned int execute (function *);
+
+}; // class pass_late_warn_uninitialized
+
+unsigned int
+pass_late_warn_uninitialized::execute (function *fun)
{
basic_block bb;
- gimple_stmt_iterator gsi;
- vec<gimple> worklist = vNULL;
- struct pointer_set_t *added_to_worklist;
+ gphi_iterator gsi;
+ vec<gphi *> worklist = vNULL;
calculate_dominance_info (CDI_DOMINATORS);
calculate_dominance_info (CDI_POST_DOMINATORS);
/* Re-do the plain uninitialized variable check, as optimization may have
straightened control flow. Do this first so that we don't accidentally
get a "may be" warning when we'd have seen an "is" warning later. */
- warn_uninitialized_vars (/*warn_possibly_uninitialized=*/1);
+ warn_uninitialized_vars (/*warn_maybe_uninitialized=*/1);
timevar_push (TV_TREE_UNINIT);
- possibly_undefined_names = pointer_set_create ();
- added_to_worklist = pointer_set_create ();
+ possibly_undefined_names = new hash_set<tree>;
+ hash_set<gphi *> added_to_worklist;
/* Initialize worklist */
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, fun)
for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- gimple phi = gsi_stmt (gsi);
- size_t n, i;
-
- n = gimple_phi_num_args (phi);
-
- /* Don't look at virtual operands. */
- if (virtual_operand_p (gimple_phi_result (phi)))
- continue;
-
- for (i = 0; i < n; ++i)
- {
- tree op = gimple_phi_arg_def (phi, i);
- if (TREE_CODE (op) == SSA_NAME
- && uninit_undefined_value_p (op))
- {
- worklist.safe_push (phi);
- pointer_set_insert (added_to_worklist, phi);
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "[WORKLIST]: add to initial list: ");
- print_gimple_stmt (dump_file, phi, 0, 0);
- }
- break;
- }
- }
+ gphi *phi = gsi.phi ();
+ size_t n, i;
+
+ n = gimple_phi_num_args (phi);
+
+ /* Don't look at virtual operands. */
+ if (virtual_operand_p (gimple_phi_result (phi)))
+ continue;
+
+ for (i = 0; i < n; ++i)
+ {
+ tree op = gimple_phi_arg_def (phi, i);
+ if (TREE_CODE (op) == SSA_NAME && uninit_undefined_value_p (op))
+ {
+ worklist.safe_push (phi);
+ added_to_worklist.add (phi);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "[WORKLIST]: add to initial list: ");
+ print_gimple_stmt (dump_file, phi, 0);
+ }
+ break;
+ }
+ }
}
while (worklist.length () != 0)
{
- gimple cur_phi = 0;
+ gphi *cur_phi = 0;
cur_phi = worklist.pop ();
- warn_uninitialized_phi (cur_phi, &worklist, added_to_worklist);
+ warn_uninitialized_phi (cur_phi, &worklist, &added_to_worklist);
}
worklist.release ();
- pointer_set_destroy (added_to_worklist);
- pointer_set_destroy (possibly_undefined_names);
+ delete possibly_undefined_names;
possibly_undefined_names = NULL;
free_dominance_info (CDI_POST_DOMINATORS);
timevar_pop (TV_TREE_UNINIT);
return 0;
}
-static bool
-gate_warn_uninitialized (void)
-{
- return warn_uninitialized != 0;
-}
-
-namespace {
-
-const pass_data pass_data_late_warn_uninitialized =
-{
- GIMPLE_PASS, /* type */
- "uninit", /* name */
- OPTGROUP_NONE, /* optinfo_flags */
- true, /* has_gate */
- true, /* has_execute */
- TV_NONE, /* tv_id */
- PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- 0, /* todo_flags_finish */
-};
-
-class pass_late_warn_uninitialized : public gimple_opt_pass
-{
-public:
- pass_late_warn_uninitialized (gcc::context *ctxt)
- : gimple_opt_pass (pass_data_late_warn_uninitialized, ctxt)
- {}
-
- /* opt_pass methods: */
- opt_pass * clone () { return new pass_late_warn_uninitialized (ctxt_); }
- bool gate () { return gate_warn_uninitialized (); }
- unsigned int execute () { return execute_late_warn_uninitialized (); }
-
-}; // class pass_late_warn_uninitialized
-
} // anon namespace
gimple_opt_pass *
return new pass_late_warn_uninitialized (ctxt);
}
-
static unsigned int
execute_early_warn_uninitialized (void)
{
/* Currently, this pass runs always but
- execute_late_warn_uninitialized only runs with optimization. With
+ execute_late_warn_uninitialized only runs with optimization. With
optimization we want to warn about possible uninitialized as late
as possible, thus don't do it here. However, without
- optimization we need to warn here about "may be uninitialized".
- */
+ optimization we need to warn here about "may be uninitialized". */
+ calculate_dominance_info (CDI_DOMINATORS);
calculate_dominance_info (CDI_POST_DOMINATORS);
- warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize);
+ warn_uninitialized_vars (/*warn_maybe_uninitialized=*/!optimize);
- /* Post-dominator information can not be reliably updated. Free it
+ /* Post-dominator information cannot be reliably updated. Free it
after the use. */
free_dominance_info (CDI_POST_DOMINATORS);
return 0;
}
-
namespace {
const pass_data pass_data_early_warn_uninitialized =
GIMPLE_PASS, /* type */
"*early_warn_uninitialized", /* name */
OPTGROUP_NONE, /* optinfo_flags */
- true, /* has_gate */
- true, /* has_execute */
TV_TREE_UNINIT, /* tv_id */
PROP_ssa, /* properties_required */
0, /* properties_provided */
{}
/* opt_pass methods: */
- bool gate () { return gate_warn_uninitialized (); }
- unsigned int execute () { return execute_early_warn_uninitialized (); }
+ virtual bool gate (function *) { return gate_warn_uninitialized (); }
+ virtual unsigned int execute (function *)
+ {
+ return execute_early_warn_uninitialized ();
+ }
}; // class pass_early_warn_uninitialized
{
return new pass_early_warn_uninitialized (ctxt);
}
-
-
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