Loop Vectorizer - skipping "bitcast" before GEP

Vectorization of memory instruction (Load/Store) is possible when the pointer is coming from GEP. The GEP analysis allows to estimate the profit.
In some cases we have a "bitcast" between GEP and memory instruction.
I added code that skips the "bitcast".

http://reviews.llvm.org/D13886

llvm-svn: 251291

1 files changed, 16 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index c61a496b747..899b639fd12 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -254,6 +254,19 @@ static Type* ToVectorTy(Type *Scalar, unsigned VF) {
   return VectorType::get(Scalar, VF);
 }
 
+/// A helper function that returns GEP instruction and knows to skip
+/// 'bitcast'.
+static GetElementPtrInst *getGEPInstruction(Value *Ptr) {
+
+  if (isa<GetElementPtrInst>(Ptr))
+    return cast<GetElementPtrInst>(Ptr);
+
+  if (isa<BitCastInst>(Ptr) &&
+      isa<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0)))
+    return cast<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0));
+  return nullptr;
+}
+
 /// InnerLoopVectorizer vectorizes loops which contain only one basic
 /// block to a specified vectorization factor (VF).
 /// This class performs the widening of scalars into vectors, or multiple
@@ -1943,7 +1956,7 @@ int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
     return II.getConsecutiveDirection();
   }
 
-  GetElementPtrInst *Gep = dyn_cast_or_null<GetElementPtrInst>(Ptr);
+  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
   if (!Gep)
     return 0;
 
@@ -2337,7 +2350,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
   VectorParts &Entry = WidenMap.get(Instr);
 
   // Handle consecutive loads/stores.
-  GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
   if (Gep && Legal->isInductionVariable(Gep->getPointerOperand())) {
     setDebugLocFromInst(Builder, Gep);
     Value *PtrOperand = Gep->getPointerOperand();
@@ -2397,7 +2410,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
     // We don't want to update the value in the map as it might be used in
     // another expression. So don't use a reference type for "StoredVal".
     VectorParts StoredVal = getVectorValue(SI->getValueOperand());
-    
+
     for (unsigned Part = 0; Part < UF; ++Part) {
       // Calculate the pointer for the specific unroll-part.
       Value *PartPtr =