[SLP] Support for horizontal min/max reduction.

SLP vectorizer supports horizontal reductions for Add/FAdd binary
operations. Patch adds support for horizontal min/max reductions.
Function getReductionCost() is split to getArithmeticReductionCost() for
binary operation reductions and getMinMaxReductionCost() for min/max
reductions.
Patch fixes PR26956.

Differential revision: https://reviews.llvm.org/D27846

llvm-svn: 312791

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index e09138168c9..8673b1b55d9 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -484,6 +484,15 @@ int TargetTransformInfo::getArithmeticReductionCost(unsigned Opcode, Type *Ty,
   return Cost;
 }
 
+int TargetTransformInfo::getMinMaxReductionCost(Type *Ty, Type *CondTy,
+                                                bool IsPairwiseForm,
+                                                bool IsUnsigned) const {
+  int Cost =
+      TTIImpl->getMinMaxReductionCost(Ty, CondTy, IsPairwiseForm, IsUnsigned);
+  assert(Cost >= 0 && "TTI should not produce negative costs!");
+  return Cost;
+}
+
 unsigned
 TargetTransformInfo::getCostOfKeepingLiveOverCall(ArrayRef<Type *> Tys) const {
   return TTIImpl->getCostOfKeepingLiveOverCall(Tys);