diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index cdcb7114640471..c6e956db8faea2 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3442,6 +3442,11 @@ static SDValue combineCarryDiamond(SelectionDAG &DAG, const TargetLowering &TLI, return SDValue(); if (Opcode != ISD::UADDO && Opcode != ISD::USUBO) return SDValue(); + // Guarantee identical type of CarryOut + EVT CarryOutType = N->getValueType(0); + if (CarryOutType != Carry0.getValue(1).getValueType() || + CarryOutType != Carry1.getValue(1).getValueType()) + return SDValue(); // Canonicalize the add/sub of A and B (the top node in the above ASCII art) // as Carry0 and the add/sub of the carry in as Carry1 (the middle node). @@ -3489,7 +3494,7 @@ static SDValue combineCarryDiamond(SelectionDAG &DAG, const TargetLowering &TLI, // TODO: match other operations that can merge flags (ADD, etc) DAG.ReplaceAllUsesOfValueWith(Carry1.getValue(0), Merged.getValue(0)); if (N->getOpcode() == ISD::AND) - return DAG.getConstant(0, DL, MVT::i1); + return DAG.getConstant(0, DL, CarryOutType); return Merged.getValue(1); } diff --git a/llvm/test/CodeGen/X86/addcarry.ll b/llvm/test/CodeGen/X86/addcarry.ll index 3fc4ed99fad0fa..f8d32fc2d29252 100644 --- a/llvm/test/CodeGen/X86/addcarry.ll +++ b/llvm/test/CodeGen/X86/addcarry.ll @@ -1490,3 +1490,26 @@ define { i64, i64 } @addcarry_commutative_2(i64 %x0, i64 %x1, i64 %y0, i64 %y1) %r1 = insertvalue { i64, i64 } %r0, i64 %b1s, 1 ret { i64, i64 } %r1 } + +define i1 @pr84831(i64 %arg) { +; CHECK-LABEL: pr84831: +; CHECK: # %bb.0: +; CHECK-NEXT: testq %rdi, %rdi +; CHECK-NEXT: setne %al +; CHECK-NEXT: xorl %ecx, %ecx +; CHECK-NEXT: addb $-1, %al +; CHECK-NEXT: adcq $1, %rcx +; CHECK-NEXT: setb %al +; CHECK-NEXT: retq + %a = icmp ult i64 0, %arg + %add1 = add i64 0, 1 + %carryout1 = icmp ult i64 %add1, 0 + %b = zext i1 %a to i64 + %add2 = add i64 %add1, %b + %carryout2 = icmp ult i64 %add2, %add1 + %zc1 = zext i1 %carryout1 to i63 + %zc2 = zext i1 %carryout2 to i63 + %or = or i63 %zc1, %zc2 + %trunc = trunc i63 %or to i1 + ret i1 %trunc +}