4 files changed, 12 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index e046984ffc3..3a7b3c4db6d 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -155,6 +155,10 @@ bool TargetTransformInfo::isLSRCostLess(LSRCost &C1, LSRCost &C2) const {
   return TTIImpl->isLSRCostLess(C1, C2);
 }
 
+bool TargetTransformInfo::canMacroFuseCmp() const {
+  return TTIImpl->canMacroFuseCmp();
+}
+
 bool TargetTransformInfo::isLegalMaskedStore(Type *DataType) const {
   return TTIImpl->isLegalMaskedStore(DataType);
 }
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 8571be8cd2b..adda3490819 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -2482,6 +2482,10 @@ bool X86TTIImpl::isLSRCostLess(TargetTransformInfo::LSRCost &C1,
                     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)
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.h b/llvm/lib/Target/X86/X86TargetTransformInfo.h
index 6f01a6fd11d..3df89903882 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.h
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.h
@@ -120,6 +120,7 @@ public:
                     Type *Ty);
   bool isLSRCostLess(TargetTransformInfo::LSRCost &C1,
                      TargetTransformInfo::LSRCost &C2);
+  bool canMacroFuseCmp();
   bool isLegalMaskedLoad(Type *DataType);
   bool isLegalMaskedStore(Type *DataType);
   bool isLegalMaskedGather(Type *DataType);
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 4b8e2286ed9..b7d9a258913 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1343,14 +1343,15 @@ void Cost::RateFormula(const TargetTransformInfo &TTI,
 
   // If ICmpZero formula ends with not 0, it could not be replaced by
   // just add or sub. We'll need to compare final result of AddRec.
-  // That means we'll need an additional instruction.
+  // That means we'll need an additional instruction. But if the target can
+  // macro-fuse a compare with a branch, don't count this extra instruction.
   // For -10 + {0, +, 1}:
   // i = i + 1;
   // cmp i, 10
   //
   // For {-10, +, 1}:
   // i = i + 1;
-  if (LU.Kind == LSRUse::ICmpZero && !F.hasZeroEnd())
+  if (LU.Kind == LSRUse::ICmpZero && !F.hasZeroEnd() && !TTI.canMacroFuseCmp())
     C.Insns++;
   // Each new AddRec adds 1 instruction to calculation.
   C.Insns += (C.AddRecCost - PrevAddRecCost);