Teach the SLP Vectorizer that keeping some values live over a callsite can have a cost.

Some types, such as 128-bit vector types on AArch64, don't have any callee-saved registers. So if a value needs to stay live over a callsite, it must be spilled and refilled. This cost is now taken into account.

llvm-svn: 214859

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index 888b5cef2f8..7ac22303deb 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -230,6 +230,11 @@ unsigned TargetTransformInfo::getReductionCost(unsigned Opcode, Type *Ty,
   return PrevTTI->getReductionCost(Opcode, Ty, IsPairwise);
 }
 
+unsigned TargetTransformInfo::getCostOfKeepingLiveOverCall(ArrayRef<Type*> Tys)
+  const {
+  return PrevTTI->getCostOfKeepingLiveOverCall(Tys);
+}
+
 namespace {
 
 struct NoTTI final : ImmutablePass, TargetTransformInfo {
@@ -613,6 +618,11 @@ struct NoTTI final : ImmutablePass, TargetTransformInfo {
   unsigned getReductionCost(unsigned, Type *, bool) const override {
     return 1;
   }
+
+  unsigned getCostOfKeepingLiveOverCall(ArrayRef<Type*> Tys) const override {
+    return 0;
+  }
+
 };
 
 } // end anonymous namespace