summaryrefslogtreecommitdiffstats
path: root/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Transforms/Scalar/IndVarSimplify.cpp')
-rw-r--r--llvm/lib/Transforms/Scalar/IndVarSimplify.cpp99
1 files changed, 77 insertions, 22 deletions
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index b07a69cc8b4..c979613aa14 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -663,6 +663,23 @@ static Value *getZeroExtendedTruncVar(const SCEVAddRecExpr *AR,
return Rewriter.expandCodeFor(ExtendedAddRec, InsertPt);
}
+/// allUsesAreSameTyped - See whether all Uses of I are instructions
+/// with the same Opcode and the same type.
+static bool allUsesAreSameTyped(unsigned int Opcode, Instruction *I) {
+ const Type* firstType = NULL;
+ for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
+ UI != UE; ++UI) {
+ Instruction *II = dyn_cast<Instruction>(*UI);
+ if (!II || II->getOpcode() != Opcode)
+ return false;
+ if (!firstType)
+ firstType = II->getType();
+ else if (firstType != II->getType())
+ return false;
+ }
+ return true;
+}
+
bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
LI = &getAnalysis<LoopInfo>();
SE = &getAnalysis<ScalarEvolution>();
@@ -808,7 +825,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
// See if we can figure out sext(i+constant) doesn't wrap, so we can
// use a larger add. This is common in subscripting.
if (UInst && UInst->getOpcode()==Instruction::Add &&
- UInst->hasOneUse() &&
+ allUsesAreSameTyped(Instruction::SExt, UInst) &&
isa<ConstantInt>(UInst->getOperand(1)) &&
NoSignedWrap && LimitVal) {
uint64_t oldBitSize = LimitVal->getValue().getBitWidth();
@@ -827,27 +844,56 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
Value *NewAdd =
BinaryOperator::CreateAdd(TruncIndVar, newAddRHS,
UInst->getName()+".nosex", UInst);
- oldSext->replaceAllUsesWith(NewAdd);
- if (Instruction *DeadUse = dyn_cast<Instruction>(oldSext))
- DeadInsts.insert(DeadUse);
+ for (Value::use_iterator UI2 = UInst->use_begin(),
+ UE2 = UInst->use_end(); UI2 != UE2; ++UI2) {
+ Instruction *II = dyn_cast<Instruction>(UI2);
+ II->replaceAllUsesWith(NewAdd);
+ DeadInsts.insert(II);
+ }
DeadInsts.insert(UInst);
}
}
}
- if (UInst && isa<ZExtInst>(UInst) && NoUnsignedWrap) {
+ // Try for sext(i | constant). This is safe as long as the
+ // high bit of the constant is not set.
+ if (UInst && UInst->getOpcode()==Instruction::Or &&
+ allUsesAreSameTyped(Instruction::SExt, UInst) && NoSignedWrap &&
+ isa<ConstantInt>(UInst->getOperand(1))) {
+ ConstantInt* RHS = dyn_cast<ConstantInt>(UInst->getOperand(1));
+ if (!RHS->getValue().isNegative()) {
+ uint64_t newBitSize = LargestType->getPrimitiveSizeInBits();
+ SExtInst* oldSext = dyn_cast<SExtInst>(UInst->use_begin());
+ Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType,
+ L, oldSext->getType(), Rewriter,
+ InsertPt);
+ APInt APcopy = APInt(RHS->getValue());
+ ConstantInt* newRHS =ConstantInt::get(APcopy.sext(newBitSize));
+ Value *NewAdd =
+ BinaryOperator::CreateOr(TruncIndVar, newRHS,
+ UInst->getName()+".nosex", UInst);
+ for (Value::use_iterator UI2 = UInst->use_begin(),
+ UE2 = UInst->use_end(); UI2 != UE2; ++UI2) {
+ Instruction *II = dyn_cast<Instruction>(UI2);
+ II->replaceAllUsesWith(NewAdd);
+ DeadInsts.insert(II);
+ }
+ DeadInsts.insert(UInst);
+ }
+ }
+ // A zext of a signed variable known not to overflow is still safe.
+ if (UInst && isa<ZExtInst>(UInst) && (NoUnsignedWrap || NoSignedWrap)) {
Value *TruncIndVar = getZeroExtendedTruncVar(AR, SE, LargestType, L,
UInst->getType(), Rewriter, InsertPt);
UInst->replaceAllUsesWith(TruncIndVar);
DeadInsts.insert(UInst);
}
- // If we have zext(i&constant), we can use the larger variable. This
- // is not common but is a bottleneck in Openssl.
+ // If we have zext(i&constant), it's always safe to use the larger
+ // variable. This is not common but is a bottleneck in Openssl.
// (RHS doesn't have to be constant. There should be a better approach
// than bottom-up pattern matching for this...)
if (UInst && UInst->getOpcode()==Instruction::And &&
- UInst->hasOneUse() &&
- isa<ConstantInt>(UInst->getOperand(1)) &&
- isa<ZExtInst>(UInst->use_begin())) {
+ allUsesAreSameTyped(Instruction::ZExt, UInst) &&
+ isa<ConstantInt>(UInst->getOperand(1))) {
uint64_t newBitSize = LargestType->getPrimitiveSizeInBits();
ConstantInt* AndRHS = dyn_cast<ConstantInt>(UInst->getOperand(1));
ZExtInst* oldZext = dyn_cast<ZExtInst>(UInst->use_begin());
@@ -858,9 +904,12 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
Value *NewAnd =
BinaryOperator::CreateAnd(TruncIndVar, newAndRHS,
UInst->getName()+".nozex", UInst);
- oldZext->replaceAllUsesWith(NewAnd);
- if (Instruction *DeadUse = dyn_cast<Instruction>(oldZext))
- DeadInsts.insert(DeadUse);
+ for (Value::use_iterator UI2 = UInst->use_begin(),
+ UE2 = UInst->use_end(); UI2 != UE2; ++UI2) {
+ Instruction *II = dyn_cast<Instruction>(UI2);
+ II->replaceAllUsesWith(NewAnd);
+ DeadInsts.insert(II);
+ }
DeadInsts.insert(UInst);
}
// If we have zext((i+constant)&constant), we can use the larger
@@ -868,33 +917,39 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
// constant being ANDed is the same size as i, which it presumably is.
// We don't need to restrict the expression being and'ed to i+const,
// but we have to promote everything in it, so it's convenient.
- if (UInst && UInst->getOpcode()==Instruction::Add &&
+ // zext((i | constant)&constant) is also valid and accepted here.
+ if (UInst && (UInst->getOpcode()==Instruction::Add ||
+ UInst->getOpcode()==Instruction::Or) &&
UInst->hasOneUse() &&
isa<ConstantInt>(UInst->getOperand(1))) {
uint64_t newBitSize = LargestType->getPrimitiveSizeInBits();
ConstantInt* AddRHS = dyn_cast<ConstantInt>(UInst->getOperand(1));
Instruction *UInst2 = dyn_cast<Instruction>(UInst->use_begin());
if (UInst2 && UInst2->getOpcode() == Instruction::And &&
- UInst2->hasOneUse() &&
- isa<ConstantInt>(UInst2->getOperand(1)) &&
- isa<ZExtInst>(UInst2->use_begin())) {
+ allUsesAreSameTyped(Instruction::ZExt, UInst2) &&
+ isa<ConstantInt>(UInst2->getOperand(1))) {
ZExtInst* oldZext = dyn_cast<ZExtInst>(UInst2->use_begin());
Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType,
L, oldZext->getType(), Rewriter, InsertPt);
ConstantInt* AndRHS = dyn_cast<ConstantInt>(UInst2->getOperand(1));
APInt APcopy = APInt(AddRHS->getValue());
ConstantInt* newAddRHS = ConstantInt::get(APcopy.zext(newBitSize));
- Value *NewAdd =
+ Value *NewAdd = ((UInst->getOpcode()==Instruction::Add) ?
BinaryOperator::CreateAdd(TruncIndVar, newAddRHS,
- UInst->getName()+".nozex", UInst2);
+ UInst->getName()+".nozex", UInst2) :
+ BinaryOperator::CreateOr(TruncIndVar, newAddRHS,
+ UInst->getName()+".nozex", UInst2));
APInt APcopy2 = APInt(AndRHS->getValue());
ConstantInt* newAndRHS = ConstantInt::get(APcopy2.zext(newBitSize));
Value *NewAnd =
BinaryOperator::CreateAnd(NewAdd, newAndRHS,
UInst->getName()+".nozex", UInst2);
- oldZext->replaceAllUsesWith(NewAnd);
- if (Instruction *DeadUse = dyn_cast<Instruction>(oldZext))
- DeadInsts.insert(DeadUse);
+ for (Value::use_iterator UI2 = UInst2->use_begin(),
+ UE2 = UInst2->use_end(); UI2 != UE2; ++UI2) {
+ Instruction *II = dyn_cast<Instruction>(UI2);
+ II->replaceAllUsesWith(NewAnd);
+ DeadInsts.insert(II);
+ }
DeadInsts.insert(UInst);
DeadInsts.insert(UInst2);
}
OpenPOWER on IntegriCloud