static void deleteIfDeadInstruction(Value *V, ScalarEvolution &SE) {
if (Instruction *I = dyn_cast<Instruction>(V))
if (isInstructionTriviallyDead(I))
- deleteDeadInstruction(I, SE);
+ deleteDeadInstruction(I, SE);
}
bool LoopIdiomRecognize::runOnLoop(Loop *L, LPPassManager &LPM) {
CurLoop = L;
+ // Disable loop idiom recognition if the function's name is a common idiom.
+ StringRef Name = L->getHeader()->getParent()->getName();
+ if (Name == "memset" || Name == "memcpy")
+ return false;
+
// The trip count of the loop must be analyzable.
SE = &getAnalysis<ScalarEvolution>();
if (!SE->hasLoopInvariantBackedgeTakenCount(L))
/// processLoopStore - See if this store can be promoted to a memset or memcpy.
bool LoopIdiomRecognize::processLoopStore(StoreInst *SI, const SCEV *BECount) {
- if (SI->isVolatile()) return false;
+ if (!SI->isSimple()) return false;
Value *StoredVal = SI->getValueOperand();
Value *StorePtr = SI->getPointerOperand();
const SCEVAddRecExpr *LoadEv =
dyn_cast<SCEVAddRecExpr>(SE->getSCEV(LI->getOperand(0)));
if (LoadEv && LoadEv->getLoop() == CurLoop && LoadEv->isAffine() &&
- StoreEv->getOperand(1) == LoadEv->getOperand(1) && !LI->isVolatile())
+ StoreEv->getOperand(1) == LoadEv->getOperand(1) && LI->isSimple())
if (processLoopStoreOfLoopLoad(SI, StoreSize, StoreEv, LoadEv, BECount))
return true;
}
SplatValue = 0;
} else {
// Otherwise, this isn't an idiom we can transform. For example, we can't
- // do anything with a 3-byte store, for example.
+ // do anything with a 3-byte store.
return false;
}
// header. This allows us to insert code for it in the preheader.
BasicBlock *Preheader = CurLoop->getLoopPreheader();
IRBuilder<> Builder(Preheader->getTerminator());
- SCEVExpander Expander(*SE);
-
+ SCEVExpander Expander(*SE, "loop-idiom");
+
// Okay, we have a strided store "p[i]" of a splattable value. We can turn
// this into a memset in the loop preheader now if we want. However, this
// would be unsafe to do if there is anything else in the loop that may read
deleteIfDeadInstruction(BasePtr, *SE);
return false;
}
-
+
// Okay, everything looks good, insert the memset.
// The # stored bytes is (BECount+1)*Size. Expand the trip count out to
// pointer size if it isn't already.
- const Type *IntPtr = TD->getIntPtrType(DestPtr->getContext());
+ Type *IntPtr = TD->getIntPtrType(DestPtr->getContext());
BECount = SE->getTruncateOrZeroExtend(BECount, IntPtr);
const SCEV *NumBytesS = SE->getAddExpr(BECount, SE->getConstant(IntPtr, 1),
// header. This allows us to insert code for it in the preheader.
BasicBlock *Preheader = CurLoop->getLoopPreheader();
IRBuilder<> Builder(Preheader->getTerminator());
- SCEVExpander Expander(*SE);
-
+ SCEVExpander Expander(*SE, "loop-idiom");
+
// Okay, we have a strided store "p[i]" of a loaded value. We can turn
// this into a memcpy in the loop preheader now if we want. However, this
// would be unsafe to do if there is anything else in the loop that may read
Expander.expandCodeFor(StoreEv->getStart(),
Builder.getInt8PtrTy(SI->getPointerAddressSpace()),
Preheader->getTerminator());
-
+
if (mayLoopAccessLocation(StoreBasePtr, AliasAnalysis::ModRef,
CurLoop, BECount, StoreSize,
getAnalysis<AliasAnalysis>(), SI)) {
deleteIfDeadInstruction(StoreBasePtr, *SE);
return false;
}
-
+
// Okay, everything is safe, we can transform this!
-
+
// The # stored bytes is (BECount+1)*Size. Expand the trip count out to
// pointer size if it isn't already.
- const Type *IntPtr = TD->getIntPtrType(SI->getContext());
+ Type *IntPtr = TD->getIntPtrType(SI->getContext());
BECount = SE->getTruncateOrZeroExtend(BECount, IntPtr);
const SCEV *NumBytesS = SE->getAddExpr(BECount, SE->getConstant(IntPtr, 1),
DEBUG(dbgs() << " Formed memcpy: " << *NewCall << "\n"
<< " from load ptr=" << *LoadEv << " at: " << *LI << "\n"
<< " from store ptr=" << *StoreEv << " at: " << *SI << "\n");
-
+
// Okay, the memset has been formed. Zap the original store and anything that
// feeds into it.