[TTI] Refine the cost of EXT in getUserCost()

Now, getUserCost() only checks the src and dst types of EXT to decide it is free
or not. This change first checks the types, then calls isExtFreeImpl(), and
check if EXT can form ExtLoad at last. Currently, only AArch64 has customized
implementation of isExtFreeImpl() to check if EXT can be folded into its use.

Differential Revision: https://reviews.llvm.org/D34458

llvm-svn: 308076

2 files changed, 6 insertions, 19 deletions

diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index 94bbc58541a..25813c65037 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -82,6 +82,11 @@ int TargetTransformInfo::getGEPCost(Type *PointeeType, const Value *Ptr,
   return TTIImpl->getGEPCost(PointeeType, Ptr, Operands);
 }
 
+int TargetTransformInfo::getExtCost(const Instruction *I,
+                                    const Value *Src) const {
+  return TTIImpl->getExtCost(I, Src);
+}
+
 int TargetTransformInfo::getIntrinsicCost(
     Intrinsic::ID IID, Type *RetTy, ArrayRef<const Value *> Arguments) const {
   int Cost = TTIImpl->getIntrinsicCost(IID, RetTy, Arguments);
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index b7155ac2480..871e4fa2444 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -4847,25 +4847,7 @@ bool CodeGenPrepare::canFormExtLd(
   if (!HasPromoted && LI->getParent() == Inst->getParent())
     return false;
 
-  EVT VT = TLI->getValueType(*DL, Inst->getType());
-  EVT LoadVT = TLI->getValueType(*DL, LI->getType());
-
-  // If the load has other users and the truncate is not free, this probably
-  // isn't worthwhile.
-  if (!LI->hasOneUse() && (TLI->isTypeLegal(LoadVT) || !TLI->isTypeLegal(VT)) &&
-      !TLI->isTruncateFree(Inst->getType(), LI->getType()))
-    return false;
-
-  // Check whether the target supports casts folded into loads.
-  unsigned LType;
-  if (isa<ZExtInst>(Inst))
-    LType = ISD::ZEXTLOAD;
-  else {
-    assert(isa<SExtInst>(Inst) && "Unexpected ext type!");
-    LType = ISD::SEXTLOAD;
-  }
-
-  return TLI->isLoadExtLegal(LType, VT, LoadVT);
+  return TLI->isExtLoad(LI, Inst, *DL);
 }
 
 /// Move a zext or sext fed by a load into the same basic block as the load,