[LoopStrengthReduce, x86] don't add cost for a cmp that will be macro-fused (PR35681)
In the motivating case from PR35681 and represented by the macro-fuse-cmp test:
https://bugs.llvm.org/show_bug.cgi?id=35681
...there's a 37 -> 31 byte size win for the loop because we eliminate the big base
address offsets.
SPEC2017 on Ryzen shows no significant perf difference.
Differential Revision: https://reviews.llvm.org/D42607
llvm-svn: 324289
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 8571be8..adda349 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -2482,6 +2482,10 @@
C2.ScaleCost, C2.ImmCost, C2.SetupCost);
}
+bool X86TTIImpl::canMacroFuseCmp() {
+ return ST->hasMacroFusion();
+}
+
bool X86TTIImpl::isLegalMaskedLoad(Type *DataTy) {
// The backend can't handle a single element vector.
if (isa<VectorType>(DataTy) && DataTy->getVectorNumElements() == 1)