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[X86] Disable loop unrolling in loop vectorization pass when VF is 1.

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The patch disabled unrolling in loop vectorization pass when VF==1 on x86 architecture,
by setting MaxInterleaveFactor to 1. Unrolling in loop vectorization pass may introduce
the cost of overflow check, memory boundary check and extra prologue/epilogue code when
regular unroller will unroll the loop another time. Disable it when VF==1 remove the
unnecessary cost on x86. The same can be done for other platforms after verifying
interleaving/memory bound checking to be not perf critical on those platforms.

Differential Revision: http://reviews.llvm.org/D9515


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236613 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Wei Mi
2015-05-06 17:12:25 +00:00
parent 530a574a9d
commit cac51be31f
16 changed files with 64 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
lib/Target/R600/AMDGPUTargetTransformInfo.cpp
View File

@@ -76,7 +76,7 @@ unsigned AMDGPUTTIImpl::getNumberOfRegisters(bool Vec) {
unsigned AMDGPUTTIImpl::getRegisterBitWidth(bool) { return 32; }
unsigned AMDGPUTTIImpl::getMaxInterleaveFactor() {
unsigned AMDGPUTTIImpl::getMaxInterleaveFactor(unsigned VF) {
// Semi-arbitrary large amount.
return 64;
}

2
lib/Target/R600/AMDGPUTargetTransformInfo.h
View File

@@ -70,7 +70,7 @@ public:
unsigned getNumberOfRegisters(bool Vector);
unsigned getRegisterBitWidth(bool Vector);
unsigned getMaxInterleaveFactor();
unsigned getMaxInterleaveFactor(unsigned VF);
};
} // end namespace llvm