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Fix InstCombine/2004-08-10-BoolSetCC.ll, a bug that is miscompiling

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176.gcc.  Note that this is apparently not the only bug miscompiling gcc
though. :(


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15639 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-08-11 00:50:51 +00:00
parent 287433594b
commit 5dbef2207e
1 changed files with 21 additions and 22 deletions
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43
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -1392,34 +1392,33 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
// setcc's with boolean values can always be turned into bitwise operations
if (Ty == Type::BoolTy) {
// If this is <, >, or !=, we can change this into a simple xor instruction
if (!isTrueWhenEqual(I))
return BinaryOperator::createXor(Op0, Op1);
// Otherwise we need to make a temporary intermediate instruction and insert
// it into the instruction stream. This is what we are after:
//
// seteq bool %A, %B -> ~(A^B)
// setle bool %A, %B -> ~A | B
// setge bool %A, %B -> A | ~B
//
if (I.getOpcode() == Instruction::SetEQ) { // seteq case
switch (I.getOpcode()) {
default: assert(0 && "Invalid setcc instruction!");
case Instruction::SetEQ: { // seteq bool %A, %B -> ~(A^B)
Instruction *Xor = BinaryOperator::createXor(Op0, Op1, I.getName()+"tmp");
InsertNewInstBefore(Xor, I);
return BinaryOperator::createNot(Xor);
}
case Instruction::SetNE:
return BinaryOperator::createXor(Op0, Op1);
// Handle the setXe cases...
assert(I.getOpcode() == Instruction::SetGE ||
I.getOpcode() == Instruction::SetLE);
if (I.getOpcode() == Instruction::SetGE)
case Instruction::SetGT:
std::swap(Op0, Op1); // Change setgt -> setlt
// FALL THROUGH
case Instruction::SetLT: { // setlt bool A, B -> ~X & Y
Instruction *Not = BinaryOperator::createNot(Op0, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::createAnd(Not, Op1);
}
case Instruction::SetGE:
std::swap(Op0, Op1); // Change setge -> setle
// Now we just have the SetLE case.
Instruction *Not = BinaryOperator::createNot(Op0, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::createOr(Not, Op1);
// FALL THROUGH
case Instruction::SetLE: { // setle bool %A, %B -> ~A | B
Instruction *Not = BinaryOperator::createNot(Op0, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::createOr(Not, Op1);
}
}
}
// See if we are doing a comparison between a constant and an instruction that