Use getStoreSize() in various places instead of 'BitSize >> 3'.

This is needed for cases when the memory access is not as big as the width of
the data type. For instance, storing i1 (1 bit) would be done in a byte (8
bits).

Using 'BitSize >> 3' (or '/ 8') would e.g. give the memory access of an i1 a
size of 0, which for instance makes alias analysis return NoAlias even when
it shouldn't.

There are no tests as this was done as a follow-up to the bugfix for the case
where this was discovered (r318824). This handles more similar cases.

Review: Björn Petterson
https://reviews.llvm.org/D40339

llvm-svn: 319173

1 files changed, 4 insertions, 11 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 7234b97f64d..3e331cddb4f 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -334,13 +334,6 @@ bool LoopIdiomRecognize::runOnCountableLoop() {
   return MadeChange;
 }
 
-static unsigned getStoreSizeInBytes(StoreInst *SI, const DataLayout *DL) {
-  uint64_t SizeInBits = DL->getTypeSizeInBits(SI->getValueOperand()->getType());
-  assert(((SizeInBits & 7) || (SizeInBits >> 32) == 0) &&
-         "Don't overflow unsigned.");
-  return (unsigned)SizeInBits >> 3;
-}
-
 static APInt getStoreStride(const SCEVAddRecExpr *StoreEv) {
   const SCEVConstant *ConstStride = cast<SCEVConstant>(StoreEv->getOperand(1));
   return ConstStride->getAPInt();
@@ -458,7 +451,7 @@ LoopIdiomRecognize::isLegalStore(StoreInst *SI) {
     // Check to see if the stride matches the size of the store.  If so, then we
     // know that every byte is touched in the loop.
     APInt Stride = getStoreStride(StoreEv);
-    unsigned StoreSize = getStoreSizeInBytes(SI, DL);
+    unsigned StoreSize = DL->getTypeStoreSize(SI->getValueOperand()->getType());
     if (StoreSize != Stride && StoreSize != -Stride)
       return LegalStoreKind::None;
 
@@ -597,7 +590,7 @@ bool LoopIdiomRecognize::processLoopStores(SmallVectorImpl<StoreInst *> &SL,
     const SCEVAddRecExpr *FirstStoreEv =
         cast<SCEVAddRecExpr>(SE->getSCEV(FirstStorePtr));
     APInt FirstStride = getStoreStride(FirstStoreEv);
-    unsigned FirstStoreSize = getStoreSizeInBytes(SL[i], DL);
+    unsigned FirstStoreSize = DL->getTypeStoreSize(SL[i]->getValueOperand()->getType());
 
     // See if we can optimize just this store in isolation.
     if (FirstStride == FirstStoreSize || -FirstStride == FirstStoreSize) {
@@ -690,7 +683,7 @@ bool LoopIdiomRecognize::processLoopStores(SmallVectorImpl<StoreInst *> &SL,
         break;
       AdjacentStores.insert(I);
 
-      StoreSize += getStoreSizeInBytes(I, DL);
+      StoreSize += DL->getTypeStoreSize(I->getValueOperand()->getType());
       // Move to the next value in the chain.
       I = ConsecutiveChain[I];
     }
@@ -964,7 +957,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(StoreInst *SI,
   Value *StorePtr = SI->getPointerOperand();
   const SCEVAddRecExpr *StoreEv = cast<SCEVAddRecExpr>(SE->getSCEV(StorePtr));
   APInt Stride = getStoreStride(StoreEv);
-  unsigned StoreSize = getStoreSizeInBytes(SI, DL);
+  unsigned StoreSize = DL->getTypeStoreSize(SI->getValueOperand()->getType());
   bool NegStride = StoreSize == -Stride;
 
   // The store must be feeding a non-volatile load.