Peer through sext/zext when looking for not(cmp).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51819 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 6222d2a..89c49c1 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -5013,6 +5013,25 @@
FCI->getOperand(0), FCI->getOperand(1));
}
+ // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
+ if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
+ if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
+ if (CI->hasOneUse() && Op0C->hasOneUse()) {
+ Instruction::CastOps Opcode = Op0C->getOpcode();
+ if (Opcode == Instruction::ZExt || Opcode == Instruction::SExt) {
+ if (RHS == ConstantExpr::getCast(Opcode, ConstantInt::getTrue(),
+ Op0C->getDestTy())) {
+ Instruction *NewCI = InsertNewInstBefore(CmpInst::Create(
+ CI->getOpcode(), CI->getInversePredicate(),
+ CI->getOperand(0), CI->getOperand(1)), I);
+ NewCI->takeName(CI);
+ return CastInst::Create(Opcode, NewCI, Op0C->getType());
+ }
+ }
+ }
+ }
+ }
+
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
// ~(c-X) == X-c-1 == X+(-c-1)
if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue())
@@ -5206,6 +5225,7 @@
}
}
}
+
return Changed ? &I : 0;
}