- if (!DepInfo.isClobber())
- return false;
-
- if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(DepInfo.getInst()))
- return processMemCpyMemCpyDependence(M, MDep, CopySize->getZExtValue());
-
- if (CallInst *C = dyn_cast<CallInst>(DepInfo.getInst())) {
- if (performCallSlotOptzn(M, M->getDest(), M->getSource(),
- CopySize->getZExtValue(), C)) {
+ if (DepInfo.isClobber()) {
+ if (CallInst *C = dyn_cast<CallInst>(DepInfo.getInst())) {
+ if (performCallSlotOptzn(M, M->getDest(), M->getSource(),
+ CopySize->getZExtValue(), M->getAlignment(),
+ C)) {
+ MD->removeInstruction(M);
+ M->eraseFromParent();
+ return true;
+ }
+ }
+ }
+
+ AliasAnalysis::Location SrcLoc = AliasAnalysis::getLocationForSource(M);
+ MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(SrcLoc, true,
+ M, M->getParent());
+ if (SrcDepInfo.isClobber()) {
+ if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(SrcDepInfo.getInst()))
+ return processMemCpyMemCpyDependence(M, MDep, CopySize->getZExtValue());
+ } else if (SrcDepInfo.isDef()) {
+ Instruction *I = SrcDepInfo.getInst();
+ bool hasUndefContents = false;
+
+ if (isa<AllocaInst>(I)) {
+ hasUndefContents = true;
+ } else if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+ if (II->getIntrinsicID() == Intrinsic::lifetime_start)
+ if (ConstantInt *LTSize = dyn_cast<ConstantInt>(II->getArgOperand(0)))
+ if (LTSize->getZExtValue() >= CopySize->getZExtValue())
+ hasUndefContents = true;
+ }
+
+ if (hasUndefContents) {