[InstCombine] fold udiv with sext bool divisor
Note: I didn't add a hasOneUse() check because the existing,
related fold doesn't have that check. I suspect that the
improved analysis and codegen make these some of the rare
canonicalization cases where we allow an increase in
instructions.
llvm-svn: 335597
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index bb714d0..7a8f2c2 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -954,9 +954,15 @@
// Op0 / C where C is large (negative) --> zext (Op0 >= C)
// TODO: Could use isKnownNegative() to handle non-constant values.
+ Type *Ty = I.getType();
if (match(Op1, m_Negative())) {
Value *Cmp = Builder.CreateICmpUGE(Op0, Op1);
- return CastInst::CreateZExtOrBitCast(Cmp, I.getType());
+ return CastInst::CreateZExtOrBitCast(Cmp, Ty);
+ }
+ // Op0 / (sext i1 X) --> zext (Op0 == -1) (if X is 0, the div is undefined)
+ if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) {
+ Value *Cmp = Builder.CreateICmpEQ(Op0, ConstantInt::getAllOnesValue(Ty));
+ return CastInst::CreateZExtOrBitCast(Cmp, Ty);
}
if (Instruction *NarrowDiv = narrowUDivURem(I, Builder))