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[Bug target/64753] Redundant cmp instruction on x86_64
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 28 Jan 2015 13:31:03 +0000
- Subject: [Bug target/64753] Redundant cmp instruction on x86_64
- Auto-submitted: auto-generated
- References: <bug-64753-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64753
--- Comment #2 from UroÅ Bizjak <ubizjak at gmail dot com> ---
(In reply to Rasmus Villemoes from comment #0)
> At the two places marked # we do a cmp and a conditional jump to .L3, where
> for good measure the same cmp is done again... there's no other path to .L3,
> so it would seem that simply omitting that extra cmp should be ok.
IIRC postreload redundant compare elimination pass removes these redundant
compares. Unfortunately, the pass is not yet enabled for x86 targets.