case Instruction::Xor:
// For the xor case, we can xor two constants together, eliminating
// the explicit xor.
- if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1)))
- return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
+ if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1))) {
+ return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
ConstantExpr::getXor(RHS, BOC));
-
- // FALLTHROUGH
+ } else if (RHSV == 0) {
+ // Replace ((xor A, B) != 0) with (A != B)
+ return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
+ BO->getOperand(1));
+ }
+ break;
case Instruction::Sub:
- // Replace (([sub|xor] A, B) != 0) with (A != B)
- if (RHSV == 0)
+ // Replace ((sub A, B) != C) with (B != A-C) if A & C are constants.
+ if (ConstantInt *BOp0C = dyn_cast<ConstantInt>(BO->getOperand(0))) {
+ if (BO->hasOneUse())
+ return new ICmpInst(ICI.getPredicate(), BO->getOperand(1),
+ ConstantExpr::getSub(BOp0C, RHS));
+ } else if (RHSV == 0) {
+ // Replace ((sub A, B) != 0) with (A != B)
return new ICmpInst(ICI.getPredicate(), BO->getOperand(0),
BO->getOperand(1));
+ }
break;
-
case Instruction::Or:
// If bits are being or'd in that are not present in the constant we
// are comparing against, then the comparison could never succeed!
%ret = icmp eq i32 %and, 128
ret i1 %ret
}
+
+; CHECK: @test55
+; CHECK-NEXT: icmp eq i32 %a, -123
+define i1 @test55(i32 %a) {
+ %sub = sub i32 0, %a
+ %cmp = icmp eq i32 %sub, 123
+ ret i1 %cmp
+}
+
+; CHECK: @test56
+; CHECK-NEXT: icmp eq i32 %a, -113
+define i1 @test56(i32 %a) {
+ %sub = sub i32 10, %a
+ %cmp = icmp eq i32 %sub, 123
+ ret i1 %cmp
+}