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| author | Manman Ren <mren@apple.com> | 2012-06-01 19:49:33 +0000 |
|---|---|---|
| committer | Manman Ren <mren@apple.com> | 2012-06-01 19:49:33 +0000 |
| commit | 73c2f7f5ed767a6fc062fd198551be902b7b7d5b (patch) | |
| tree | 0e7ddc57a166cd5f076eac14c404412061d88d0f /lib/Target/X86/X86InstrArithmetic.td | |
| parent | 68f25571e759c1fcf2da206109647259f49f7416 (diff) | |
| download | external_llvm-73c2f7f5ed767a6fc062fd198551be902b7b7d5b.zip external_llvm-73c2f7f5ed767a6fc062fd198551be902b7b7d5b.tar.gz external_llvm-73c2f7f5ed767a6fc062fd198551be902b7b7d5b.tar.bz2 | |
X86: peephole optimization to remove cmp instruction
This patch will optimize the following:
sub r1, r3
cmp r3, r1 or cmp r1, r3
bge L1
TO
sub r1, r3
bge L1 or ble L1
If the branch instruction can use flag from "sub", then we can eliminate
the "cmp" instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157831 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/X86InstrArithmetic.td')
| -rw-r--r-- | lib/Target/X86/X86InstrArithmetic.td | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/Target/X86/X86InstrArithmetic.td b/lib/Target/X86/X86InstrArithmetic.td index 0eee083..c2b59b4 100644 --- a/lib/Target/X86/X86InstrArithmetic.td +++ b/lib/Target/X86/X86InstrArithmetic.td @@ -1143,7 +1143,9 @@ let Uses = [EFLAGS] in { 0, 0>; } +let isCompare = 1 in { defm CMP : ArithBinOp_F<0x38, 0x3A, 0x3C, "cmp", MRM7r, MRM7m, X86cmp, 0, 0>; +} //===----------------------------------------------------------------------===// |