+ return AMemSet;
+}
+
+
+bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
+ if (!SI->isSimple()) return false;
+
+ if (TD == 0) return false;
+
+ // Detect cases where we're performing call slot forwarding, but
+ // happen to be using a load-store pair to implement it, rather than
+ // a memcpy.
+ if (LoadInst *LI = dyn_cast<LoadInst>(SI->getOperand(0))) {
+ if (LI->isSimple() && LI->hasOneUse() &&
+ LI->getParent() == SI->getParent()) {
+ MemDepResult ldep = MD->getDependency(LI);
+ CallInst *C = 0;
+ if (ldep.isClobber() && !isa<MemCpyInst>(ldep.getInst()))
+ C = dyn_cast<CallInst>(ldep.getInst());
+
+ if (C) {
+ // Check that nothing touches the dest of the "copy" between
+ // the call and the store.
+ AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
+ AliasAnalysis::Location StoreLoc = AA.getLocation(SI);
+ for (BasicBlock::iterator I = --BasicBlock::iterator(SI),
+ E = C; I != E; --I) {
+ if (AA.getModRefInfo(&*I, StoreLoc) != AliasAnalysis::NoModRef) {
+ C = 0;
+ break;
+ }
+ }
+ }
+
+ if (C) {
+ bool changed = performCallSlotOptzn(LI,
+ SI->getPointerOperand()->stripPointerCasts(),
+ LI->getPointerOperand()->stripPointerCasts(),
+ TD->getTypeStoreSize(SI->getOperand(0)->getType()), C);
+ if (changed) {
+ MD->removeInstruction(SI);
+ SI->eraseFromParent();
+ MD->removeInstruction(LI);
+ LI->eraseFromParent();
+ ++NumMemCpyInstr;
+ return true;
+ }
+ }
+ }
+ }
+
+ // There are two cases that are interesting for this code to handle: memcpy
+ // and memset. Right now we only handle memset.
+
+ // Ensure that the value being stored is something that can be memset'able a
+ // byte at a time like "0" or "-1" or any width, as well as things like
+ // 0xA0A0A0A0 and 0.0.
+ if (Value *ByteVal = isBytewiseValue(SI->getOperand(0)))
+ if (Instruction *I = tryMergingIntoMemset(SI, SI->getPointerOperand(),
+ ByteVal)) {
+ BBI = I; // Don't invalidate iterator.
+ return true;
+ }
+
+ return false;
+}
+
+bool MemCpyOpt::processMemSet(MemSetInst *MSI, BasicBlock::iterator &BBI) {
+ // See if there is another memset or store neighboring this memset which
+ // allows us to widen out the memset to do a single larger store.
+ if (isa<ConstantInt>(MSI->getLength()) && !MSI->isVolatile())
+ if (Instruction *I = tryMergingIntoMemset(MSI, MSI->getDest(),
+ MSI->getValue())) {
+ BBI = I; // Don't invalidate iterator.
+ return true;
+ }
+ return false;