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| author | Andrew Trick <atrick@apple.com> | 2011-04-14 05:15:06 +0000 |
|---|---|---|
| committer | Andrew Trick <atrick@apple.com> | 2011-04-14 05:15:06 +0000 |
| commit | 12f0dc6bb556976f22d89ebcf42bce273c9e7d38 (patch) | |
| tree | d3c41e0b3c32158742854b3a12ac286d59505e71 /test/CodeGen/X86/pr2659.ll | |
| parent | b57b06647ead66113a97d84c3b3d332afe807dd6 (diff) | |
| download | external_llvm-12f0dc6bb556976f22d89ebcf42bce273c9e7d38.zip external_llvm-12f0dc6bb556976f22d89ebcf42bce273c9e7d38.tar.gz external_llvm-12f0dc6bb556976f22d89ebcf42bce273c9e7d38.tar.bz2 | |
In the pre-RA scheduler, maintain cmp+br proximity.
This is done by pushing physical register definitions close to their
use, which happens to handle flag definitions if they're not glued to
the branch. This seems to be generally a good thing though, so I
didn't need to add a target hook yet.
The primary motivation is to generate code closer to what people
expect and rule out missed opportunity from enabling macro-op
fusion. As a side benefit, we get several 2-5% gains on x86
benchmarks. There is one regression:
SingleSource/Benchmarks/Shootout/lists slows down be -10%. But this is
an independent scheduler bug that will be tracked separately.
See rdar://problem/9283108.
Incidentally, pre-RA scheduling is only half the solution. Fixing the
later passes is tracked by:
<rdar://problem/8932804> [pre-RA-sched] on x86, attempt to schedule CMP/TEST adjacent with condition jump
Fixes:
<rdar://problem/9262453> Scheduler unnecessary break of cmp/jump fusion
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129508 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGen/X86/pr2659.ll')
| -rw-r--r-- | test/CodeGen/X86/pr2659.ll | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/test/CodeGen/X86/pr2659.ll b/test/CodeGen/X86/pr2659.ll index 54d043d..ef0f9ea 100644 --- a/test/CodeGen/X86/pr2659.ll +++ b/test/CodeGen/X86/pr2659.ll @@ -18,7 +18,8 @@ forcond.preheader: ; preds = %entry ; CHECK: movl $1 ; CHECK-NOT: xorl ; CHECK-NOT: movl -; CHECK-NEXT: je +; CHECK-NOT: LBB +; CHECK: je ifthen: ; preds = %entry ret i32 0 |