Add support for PHI-translating sext, zext, and trunc instructions,
enabling more PRE. PR8586.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119704 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PHITransAddr.cpp b/lib/Analysis/PHITransAddr.cpp
index a9ccab1..178d29e 100644
--- a/lib/Analysis/PHITransAddr.cpp
+++ b/lib/Analysis/PHITransAddr.cpp
@@ -20,9 +20,12 @@
static bool CanPHITrans(Instruction *Inst) {
if (isa<PHINode>(Inst) ||
- isa<BitCastInst>(Inst) ||
isa<GetElementPtrInst>(Inst))
return true;
+
+ if (isa<CastInst>(Inst) &&
+ Inst->isSafeToSpeculativelyExecute())
+ return true;
if (Inst->getOpcode() == Instruction::Add &&
isa<ConstantInt>(Inst->getOperand(1)))
@@ -177,26 +180,29 @@
// or because we just incorporated it into the expression). See if its
// operands need to be phi translated, and if so, reconstruct it.
- if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
- Value *PHIIn = PHITranslateSubExpr(BC->getOperand(0), CurBB, PredBB, DT);
+ if (CastInst *Cast = dyn_cast<CastInst>(Inst)) {
+ if (!Cast->isSafeToSpeculativelyExecute()) return 0;
+ Value *PHIIn = PHITranslateSubExpr(Cast->getOperand(0), CurBB, PredBB, DT);
if (PHIIn == 0) return 0;
- if (PHIIn == BC->getOperand(0))
- return BC;
+ if (PHIIn == Cast->getOperand(0))
+ return Cast;
// Find an available version of this cast.
// Constants are trivial to find.
if (Constant *C = dyn_cast<Constant>(PHIIn))
- return AddAsInput(ConstantExpr::getBitCast(C, BC->getType()));
+ return AddAsInput(ConstantExpr::getCast(Cast->getOpcode(),
+ C, Cast->getType()));
- // Otherwise we have to see if a bitcasted version of the incoming pointer
+ // Otherwise we have to see if a casted version of the incoming pointer
// is available. If so, we can use it, otherwise we have to fail.
for (Value::use_iterator UI = PHIIn->use_begin(), E = PHIIn->use_end();
UI != E; ++UI) {
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI))
- if (BCI->getType() == BC->getType() &&
- (!DT || DT->dominates(BCI->getParent(), PredBB)))
- return BCI;
+ if (CastInst *CastI = dyn_cast<CastInst>(*UI))
+ if (CastI->getOpcode() == Cast->getOpcode() &&
+ CastI->getType() == Cast->getType() &&
+ (!DT || DT->dominates(CastI->getParent(), PredBB)))
+ return CastI;
}
return 0;
}
@@ -368,16 +374,18 @@
// instruction.
Instruction *Inst = cast<Instruction>(InVal);
- // Handle bitcast of PHI translatable value.
- if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
- Value *OpVal = InsertPHITranslatedSubExpr(BC->getOperand(0),
+ // Handle cast of PHI translatable value.
+ if (CastInst *Cast = dyn_cast<CastInst>(Inst)) {
+ if (!Cast->isSafeToSpeculativelyExecute()) return 0;
+ Value *OpVal = InsertPHITranslatedSubExpr(Cast->getOperand(0),
CurBB, PredBB, DT, NewInsts);
if (OpVal == 0) return 0;
- // Otherwise insert a bitcast at the end of PredBB.
- BitCastInst *New = new BitCastInst(OpVal, InVal->getType(),
- InVal->getName()+".phi.trans.insert",
- PredBB->getTerminator());
+ // Otherwise insert a cast at the end of PredBB.
+ CastInst *New = CastInst::Create(Cast->getOpcode(),
+ OpVal, InVal->getType(),
+ InVal->getName()+".phi.trans.insert",
+ PredBB->getTerminator());
NewInsts.push_back(New);
return New;
}