Skip bitcasts while looking for GEP in LoadStoreVectorizer

Differential Revisison: https://reviews.llvm.org/D32101

llvm-svn: 301343

1 files changed, 19 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
index f709d6a516e..b0324d087fb 100644
--- a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -65,7 +65,9 @@ public:
   bool run();
 
 private:
-  Value *getPointerOperand(Value *I);
+  Value *getPointerOperand(Value *I) const;
+
+  GetElementPtrInst *getSourceGEP(Value *Src) const;
 
   unsigned getPointerAddressSpace(Value *I);
 
@@ -215,7 +217,7 @@ bool Vectorizer::run() {
   return Changed;
 }
 
-Value *Vectorizer::getPointerOperand(Value *I) {
+Value *Vectorizer::getPointerOperand(Value *I) const {
   if (LoadInst *LI = dyn_cast<LoadInst>(I))
     return LI->getPointerOperand();
   if (StoreInst *SI = dyn_cast<StoreInst>(I))
@@ -231,6 +233,19 @@ unsigned Vectorizer::getPointerAddressSpace(Value *I) {
   return -1;
 }
 
+GetElementPtrInst *Vectorizer::getSourceGEP(Value *Src) const {
+  // First strip pointer bitcasts. Make sure pointee size is the same with
+  // and without casts.
+  // TODO: a stride set by the add instruction below can match the difference
+  // in pointee type size here. Currently it will not be vectorized.
+  Value *SrcPtr = getPointerOperand(Src);
+  Value *SrcBase = SrcPtr->stripPointerCasts();
+  if (DL.getTypeStoreSize(SrcPtr->getType()->getPointerElementType()) ==
+      DL.getTypeStoreSize(SrcBase->getType()->getPointerElementType()))
+    SrcPtr = SrcBase;
+  return dyn_cast<GetElementPtrInst>(SrcPtr);
+}
+
 // FIXME: Merge with llvm::isConsecutiveAccess
 bool Vectorizer::isConsecutiveAccess(Value *A, Value *B) {
   Value *PtrA = getPointerOperand(A);
@@ -283,8 +298,8 @@ bool Vectorizer::isConsecutiveAccess(Value *A, Value *B) {
 
   // Look through GEPs after checking they're the same except for the last
   // index.
-  GetElementPtrInst *GEPA = dyn_cast<GetElementPtrInst>(getPointerOperand(A));
-  GetElementPtrInst *GEPB = dyn_cast<GetElementPtrInst>(getPointerOperand(B));
+  GetElementPtrInst *GEPA = getSourceGEP(A);
+  GetElementPtrInst *GEPB = getSourceGEP(B);
   if (!GEPA || !GEPB || GEPA->getNumOperands() != GEPB->getNumOperands())
     return false;
   unsigned FinalIndex = GEPA->getNumOperands() - 1;