[MemCpyOpt] Use LocationSize instead of ints; NFC

Trying to keep these patches super small so they're easily post-commit
verifiable, as requested in D44748.

srcSize is derived from the size of an alloca, and we quit out if the
size of that is > the size of the thing we're copying to. Hence, we
should always copy everything over, so these sizes are precise.

Don't make srcSize itself a LocationSize, since optionality isn't
helpful, and we do some comparisons against other sizes elsewhere in
that function.

llvm-svn: 350019

diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 2dd961b..3315181 100644 (file)
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -944,10 +944,10 @@ bool MemCpyOptPass::performCallSlotOptzn(Instruction *cpy, Value *cpyDest,
   // the use analysis, we also need to know that it does not sneakily
   // access dest.  We rely on AA to figure this out for us.
   AliasAnalysis &AA = LookupAliasAnalysis();
-  ModRefInfo MR = AA.getModRefInfo(C, cpyDest, srcSize);
+  ModRefInfo MR = AA.getModRefInfo(C, cpyDest, LocationSize::precise(srcSize));
   // If necessary, perform additional analysis.
   if (isModOrRefSet(MR))
-    MR = AA.callCapturesBefore(C, cpyDest, srcSize, &DT);
+    MR = AA.callCapturesBefore(C, cpyDest, LocationSize::precise(srcSize), &DT);
   if (isModOrRefSet(MR))
     return false;
 
@@ -1343,7 +1343,7 @@ bool MemCpyOptPass::processByValArgument(CallSite CS, unsigned ArgNo) {
   Type *ByValTy = cast<PointerType>(ByValArg->getType())->getElementType();
   uint64_t ByValSize = DL.getTypeAllocSize(ByValTy);
   MemDepResult DepInfo = MD->getPointerDependencyFrom(
-      MemoryLocation(ByValArg, ByValSize), true,
+      MemoryLocation(ByValArg, LocationSize::precise(ByValSize)), true,
       CS.getInstruction()->getIterator(), CS.getInstruction()->getParent());
   if (!DepInfo.isClobber())
     return false;