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This pass keeps a map of Instructions to Rank numbers,

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and was deleting Instructions without clearing the
corresponding map entry.  This led to nondeterministic
behavior if the same address got allocated to another
Instruction within a short time.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67306 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2009-03-19 17:22:53 +00:00
parent 7fae82f67a
commit f4978e2094
1 changed files with 14 additions and 8 deletions
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22
lib/Transforms/Scalar/Reassociate.cpp
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@ -196,10 +196,12 @@ static BinaryOperator *isReassociableOp(Value *V, unsigned Opcode) {
/// LowerNegateToMultiply - Replace 0-X with X*-1.
///
static Instruction *LowerNegateToMultiply(Instruction *Neg) {
static Instruction *LowerNegateToMultiply(Instruction *Neg,
std::map<Value*, unsigned> &ValueRankMap) {
Constant *Cst = ConstantInt::getAllOnesValue(Neg->getType());
Instruction *Res = BinaryOperator::CreateMul(Neg->getOperand(1), Cst, "",Neg);
ValueRankMap.erase(Neg);
Res->takeName(Neg);
Neg->replaceAllUsesWith(Res);
Neg->eraseFromParent();
@ -260,11 +262,11 @@ void Reassociate::LinearizeExprTree(BinaryOperator *I,
// transform them into multiplies by -1 so they can be reassociated.
if (I->getOpcode() == Instruction::Mul) {
if (!LHSBO && LHS->hasOneUse() && BinaryOperator::isNeg(LHS)) {
LHS = LowerNegateToMultiply(cast<Instruction>(LHS));
LHS = LowerNegateToMultiply(cast<Instruction>(LHS), ValueRankMap);
LHSBO = isReassociableOp(LHS, Opcode);
}
if (!RHSBO && RHS->hasOneUse() && BinaryOperator::isNeg(RHS)) {
RHS = LowerNegateToMultiply(cast<Instruction>(RHS));
RHS = LowerNegateToMultiply(cast<Instruction>(RHS), ValueRankMap);
RHSBO = isReassociableOp(RHS, Opcode);
}
}
@ -424,7 +426,8 @@ static bool ShouldBreakUpSubtract(Instruction *Sub) {
/// BreakUpSubtract - If we have (X-Y), and if either X is an add, or if this is
/// only used by an add, transform this into (X+(0-Y)) to promote better
/// reassociation.
static Instruction *BreakUpSubtract(Instruction *Sub) {
static Instruction *BreakUpSubtract(Instruction *Sub,
std::map<Value*, unsigned> &ValueRankMap) {
// Convert a subtract into an add and a neg instruction... so that sub
// instructions can be commuted with other add instructions...
//
@ -437,6 +440,7 @@ static Instruction *BreakUpSubtract(Instruction *Sub) {
New->takeName(Sub);
// Everyone now refers to the add instruction.
ValueRankMap.erase(Sub);
Sub->replaceAllUsesWith(New);
Sub->eraseFromParent();
@ -447,7 +451,8 @@ static Instruction *BreakUpSubtract(Instruction *Sub) {
/// ConvertShiftToMul - If this is a shift of a reassociable multiply or is used
/// by one, change this into a multiply by a constant to assist with further
/// reassociation.
static Instruction *ConvertShiftToMul(Instruction *Shl) {
static Instruction *ConvertShiftToMul(Instruction *Shl,
std::map<Value*, unsigned> &ValueRankMap){
// If an operand of this shift is a reassociable multiply, or if the shift
// is used by a reassociable multiply or add, turn into a multiply.
if (isReassociableOp(Shl->getOperand(0), Instruction::Mul) ||
@ -459,6 +464,7 @@ static Instruction *ConvertShiftToMul(Instruction *Shl) {
Instruction *Mul = BinaryOperator::CreateMul(Shl->getOperand(0), MulCst,
"", Shl);
ValueRankMap.erase(Shl);
Mul->takeName(Shl);
Shl->replaceAllUsesWith(Mul);
Shl->eraseFromParent();
@ -772,7 +778,7 @@ void Reassociate::ReassociateBB(BasicBlock *BB) {
Instruction *BI = BBI++;
if (BI->getOpcode() == Instruction::Shl &&
isa<ConstantInt>(BI->getOperand(1)))
if (Instruction *NI = ConvertShiftToMul(BI)) {
if (Instruction *NI = ConvertShiftToMul(BI, ValueRankMap)) {
MadeChange = true;
BI = NI;
}
@ -786,7 +792,7 @@ void Reassociate::ReassociateBB(BasicBlock *BB) {
// see if we can convert it to X+-Y.
if (BI->getOpcode() == Instruction::Sub) {
if (ShouldBreakUpSubtract(BI)) {
BI = BreakUpSubtract(BI);
BI = BreakUpSubtract(BI, ValueRankMap);
MadeChange = true;
} else if (BinaryOperator::isNeg(BI)) {
// Otherwise, this is a negation. See if the operand is a multiply tree
@ -794,7 +800,7 @@ void Reassociate::ReassociateBB(BasicBlock *BB) {
if (isReassociableOp(BI->getOperand(1), Instruction::Mul) &&
(!BI->hasOneUse() ||
!isReassociableOp(BI->use_back(), Instruction::Mul))) {
BI = LowerNegateToMultiply(BI);
BI = LowerNegateToMultiply(BI, ValueRankMap);
MadeChange = true;
}
}