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[Bug target/82666] [7/8 regression]: sum += (x>128 ? x : 0) puts the cmov on the critical path (at -O2)
- From: "aldyh at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 16 Jan 2018 20:29:17 +0000
- Subject: [Bug target/82666] [7/8 regression]: sum += (x>128 ? x : 0) puts the cmov on the critical path (at -O2)
- Auto-submitted: auto-generated
- References: <bug-82666-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82666
Aldy Hernandez <aldyh at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |aldyh at gcc dot gnu.org
--- Comment #3 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
I haven't looked deeply into this, but prior to Richi's PRE patch in r239414 we
had a CMOV instruction. So if anything, Richi's patch removes the problematic
instruction. It is with Bernd's patch tweaking costs in r242832 that we get
the CMOV again.
Could Bernd or someone else take a look at the cost patch to see if it's
something simple that backend experts can tackle?