2010-05-25 Paolo Bonzini <bonzini@gnu.org>

	* doc/tm.texi (STORE_FLAG_VALUE): Do not refer to sCC patterns.
	* doc/md.texi (cstoreXX4): Update for cond-optab changes.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@159814 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 28c74e278b04e8f086d7cea34d014f36d2ccb330..0546d7218354aaa4abf99f135aa7e6bee7fba09b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,9 @@
-2010-05-09  Paolo Bonzini  <bonzini@gnu.org>
+2010-05-25  Paolo Bonzini  <bonzini@gnu.org>
+
+       * doc/tm.texi (STORE_FLAG_VALUE): Do not refer to sCC patterns.
+       * doc/md.texi (cstoreXX4): Update for cond-optab changes.
+
+2010-05-25  Paolo Bonzini  <bonzini@gnu.org>
 
        PR target/43610
        * optabs.c (prepare_float_lib_cmp): Allow reversing the comparison

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index bcdbabcafdf11bbc3a25d36af9f17504c3208a84..ead8b26545808ff049b74f105071874945cc754c 100644 (file)
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -4705,20 +4705,28 @@ else must be negative.  Otherwise the instruction is not suitable and
 you should omit it from the machine description.  You describe to the
 compiler exactly which value is stored by defining the macro
 @code{STORE_FLAG_VALUE} (@pxref{Misc}).  If a description cannot be
-found that can be used for all the @samp{s@var{cond}} patterns, you
-should omit those operations from the machine description.
-
-These operations may fail, but should do so only in relatively
-uncommon cases; if they would fail for common cases involving
-integer comparisons, it is best to omit these patterns.
-
-If these operations are omitted, the compiler will usually generate code
-that copies the constant one to the target and branches around an
-assignment of zero to the target.  If this code is more efficient than
-the potential instructions used for the @samp{cstore@var{mode}4} pattern
-followed by those required to convert the result into a 1 or a zero in
-@code{SImode}, you should omit the @samp{cstore@var{mode}4} operations from
-the machine description.
+found that can be used for all the possible comparison operators, you
+should pick one and use a @code{define_expand} to map all results
+onto the one you chose.
+
+These operations may @code{FAIL}, but should do so only in relatively
+uncommon cases; if they would @code{FAIL} for common cases involving
+integer comparisons, it is best to restrict the predicates to not
+allow these operands.  Likewise if a given comparison operator will
+always fail, independent of the operands (for floating-point modes, the
+@code{ordered_comparison_operator} predicate is often useful in this case).
+
+If this pattern is omitted, the compiler will generate a conditional
+branch---for example, it may copy a constant one to the target and branching
+around an assignment of zero to the target---or a libcall.  If the predicate
+for operand 1 only rejects some operators, it will also try reordering the
+operands and/or inverting the result value (e.g.@: by an exclusive OR).
+These possibilities could be cheaper or equivalent to the instructions
+used for the @samp{cstore@var{mode}4} pattern followed by those required
+to convert a positive result from @code{STORE_FLAG_VALUE} to 1; in this
+case, you can and should make operand 1's predicate reject some operators
+in the @samp{cstore@var{mode}4} pattern, or remove the pattern altogether
+from the machine description.
 
 @cindex @code{cbranch@var{mode}4} instruction pattern
 @item @samp{cbranch@var{mode}4}

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 80e28a34b90d67208e9210e6532f95696bd0d9c1..b0175eaa1a44aca982563919bd9e16ddcb7ea674 100644 (file)
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -10264,8 +10264,8 @@ In order to enforce the representation of @code{mode},
 @defmac STORE_FLAG_VALUE
 A C expression describing the value returned by a comparison operator
 with an integral mode and stored by a store-flag instruction
-(@samp{s@var{cond}}) when the condition is true.  This description must
-apply to @emph{all} the @samp{s@var{cond}} patterns and all the
+(@samp{cstore@var{mode}4}) when the condition is true.  This description must
+apply to @emph{all} the @samp{cstore@var{mode}4} patterns and all the
 comparison operators whose results have a @code{MODE_INT} mode.
 
 A value of 1 or @minus{}1 means that the instruction implementing the
@@ -10274,7 +10274,7 @@ and 0 when the comparison is false.  Otherwise, the value indicates
 which bits of the result are guaranteed to be 1 when the comparison is
 true.  This value is interpreted in the mode of the comparison
 operation, which is given by the mode of the first operand in the
-@samp{s@var{cond}} pattern.  Either the low bit or the sign bit of
+@samp{cstore@var{mode}4} pattern.  Either the low bit or the sign bit of
 @code{STORE_FLAG_VALUE} be on.  Presently, only those bits are used by
 the compiler.
 
@@ -10347,7 +10347,7 @@ those cases, e.g., one matching
 
 Some machines can also perform @code{and} or @code{plus} operations on
 condition code values with less instructions than the corresponding
-@samp{s@var{cond}} insn followed by @code{and} or @code{plus}.  On those
+@samp{cstore@var{mode}4} insn followed by @code{and} or @code{plus}.  On those
 machines, define the appropriate patterns.  Use the names @code{incscc}
 and @code{decscc}, respectively, for the patterns which perform
 @code{plus} or @code{minus} operations on condition code values.  See