Noticed while investigating a regression for cris-elf with
r15-9239-g4d7a634f6d4102 "combine: Allow 2->2 combinations,
but with a tweak [PR116398]" (to-be-reported).
The comment was introduced when breaking out the
combine_validate_cost function, in r0-59417-g64b8935d4809f3.
I thought about wordsmithing to keep the "polarity" of the
statement, but "are equal to or cheaper than" didn't read
well.
Ok to commit?
-- >8 --
The *code* has been the same since forever, but this
comment, at a critical path, is misleading: if the new cost
is the same (like, when doing an identity replacement), then
combine_validate_cost returns true.
* combine.cc (try_combine): Correct comment about
combine_validate_cost.
---
gcc/combine.cc | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/combine.cc b/gcc/combine.cc
index 5f085187cfef..c2c1d50ca49f 100644
--- a/gcc/combine.cc
+++ b/gcc/combine.cc
@@ -4129,8 +4129,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1,
rtx_insn *i0,
}
}
- /* Only allow this combination if insn_cost reports that the
- replacement instructions are cheaper than the originals. */
+ /* Reject this combination if insn_cost reports that the replacement
+ instructions are more expensive than the originals. */
if (!combine_validate_cost (i0, i1, i2, i3, newpat, newi2pat, other_pat))
{
undo_all ();
--
2.30.2
