mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-19 04:29:21 +00:00
fdiv/frem of undef can produce undef, because the undef operand
can be a SNaN. We could be more aggressive and turn this into unreachable, but that is less nice, and not really worth it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47313 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
389056110f
commit
50b2ca4c73
@ -2590,9 +2590,13 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
|
||||
Instruction *InstCombiner::commonDivTransforms(BinaryOperator &I) {
|
||||
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
||||
|
||||
// undef / X -> 0
|
||||
if (isa<UndefValue>(Op0))
|
||||
// undef / X -> 0 for integer.
|
||||
// undef / X -> undef for FP (the undef could be a snan).
|
||||
if (isa<UndefValue>(Op0)) {
|
||||
if (Op0->getType()->isFPOrFPVector())
|
||||
return ReplaceInstUsesWith(I, Op0);
|
||||
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
|
||||
}
|
||||
|
||||
// X / undef -> undef
|
||||
if (isa<UndefValue>(Op1))
|
||||
@ -2821,13 +2825,16 @@ static Constant *GetFactor(Value *V) {
|
||||
Instruction *InstCombiner::commonRemTransforms(BinaryOperator &I) {
|
||||
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
||||
|
||||
// 0 % X == 0, we don't need to preserve faults!
|
||||
// 0 % X == 0 for integer, we don't need to preserve faults!
|
||||
if (Constant *LHS = dyn_cast<Constant>(Op0))
|
||||
if (LHS->isNullValue())
|
||||
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
|
||||
|
||||
if (isa<UndefValue>(Op0)) // undef % X -> 0
|
||||
if (isa<UndefValue>(Op0)) { // undef % X -> 0
|
||||
if (I.getType()->isFPOrFPVector())
|
||||
return ReplaceInstUsesWith(I, Op0); // X % undef -> undef (could be SNaN)
|
||||
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
|
||||
}
|
||||
if (isa<UndefValue>(Op1))
|
||||
return ReplaceInstUsesWith(I, Op1); // X % undef -> undef
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user