[InstCombine] Fold add nuw + uadd.with.overflow
Fold add nuw and uadd.with.overflow with constants if the
addition does not overflow.
Part of https://bugs.llvm.org/show_bug.cgi?id=38146.
Patch by Dan Robertson.
Differential Revision: https://reviews.llvm.org/D59471
llvm-svn: 356584
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index df80221..359f617 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2063,6 +2063,7 @@
return &CI;
break;
}
+ case Intrinsic::uadd_with_overflow:
case Intrinsic::sadd_with_overflow: {
if (Instruction *I = canonicalizeConstantArg0ToArg1(CI))
return I;
@@ -2070,25 +2071,27 @@
return I;
// Given 2 constant operands whose sum does not overflow:
+ // uaddo (X +nuw C0), C1 -> uaddo X, C0 + C1
// saddo (X +nsw C0), C1 -> saddo X, C0 + C1
Value *X;
const APInt *C0, *C1;
Value *Arg0 = II->getArgOperand(0);
Value *Arg1 = II->getArgOperand(1);
- if (match(Arg0, m_NSWAdd(m_Value(X), m_APInt(C0))) &&
- match(Arg1, m_APInt(C1))) {
+ bool IsSigned = II->getIntrinsicID() == Intrinsic::sadd_with_overflow;
+ bool HasNWAdd = IsSigned ? match(Arg0, m_NSWAdd(m_Value(X), m_APInt(C0)))
+ : match(Arg0, m_NUWAdd(m_Value(X), m_APInt(C0)));
+ if (HasNWAdd && match(Arg1, m_APInt(C1))) {
bool Overflow;
- APInt NewC = C1->sadd_ov(*C0, Overflow);
+ APInt NewC =
+ IsSigned ? C1->sadd_ov(*C0, Overflow) : C1->uadd_ov(*C0, Overflow);
if (!Overflow)
return replaceInstUsesWith(
*II, Builder.CreateBinaryIntrinsic(
- Intrinsic::sadd_with_overflow, X,
+ II->getIntrinsicID(), X,
ConstantInt::get(Arg1->getType(), NewC)));
}
-
break;
}
- case Intrinsic::uadd_with_overflow:
case Intrinsic::umul_with_overflow:
case Intrinsic::smul_with_overflow:
if (Instruction *I = canonicalizeConstantArg0ToArg1(CI))