diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 35 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/xaluo.ll | 6 |
2 files changed, 38 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 626dfaea957..d539bbeb653 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -235,6 +235,7 @@ namespace { SDValue visitADDLike(SDValue N0, SDValue N1, SDNode *LocReference); SDValue visitSUB(SDNode *N); SDValue visitADDC(SDNode *N); + SDValue visitUADDO(SDNode *N); SDValue visitSUBC(SDNode *N); SDValue visitUSUBO(SDNode *N); SDValue visitADDE(SDNode *N); @@ -1400,6 +1401,7 @@ SDValue DAGCombiner::visit(SDNode *N) { case ISD::ADD: return visitADD(N); case ISD::SUB: return visitSUB(N); case ISD::ADDC: return visitADDC(N); + case ISD::UADDO: return visitUADDO(N); case ISD::SUBC: return visitSUBC(N); case ISD::USUBO: return visitUSUBO(N); case ISD::ADDE: return visitADDE(N); @@ -1928,6 +1930,39 @@ SDValue DAGCombiner::visitADDC(SDNode *N) { return SDValue(); } +SDValue DAGCombiner::visitUADDO(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + if (VT.isVector()) + return SDValue(); + + EVT CarryVT = N->getValueType(1); + SDLoc DL(N); + + // If the flag result is dead, turn this into an ADD. + if (!N->hasAnyUseOfValue(1)) + return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1), + DAG.getUNDEF(CarryVT)); + + // canonicalize constant to RHS. + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + if (N0C && !N1C) + return DAG.getNode(ISD::UADDO, DL, N->getVTList(), N1, N0); + + // fold (uaddo x, 0) -> x + no carry out + if (isNullConstant(N1)) + return CombineTo(N, N0, DAG.getConstant(0, DL, CarryVT)); + + // If it cannot overflow, transform into an add. + if (DAG.computeOverflowKind(N0, N1) == SelectionDAG::OFK_Never) + return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1), + DAG.getConstant(0, DL, CarryVT)); + + return SDValue(); +} + SDValue DAGCombiner::visitADDE(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); diff --git a/llvm/test/CodeGen/X86/xaluo.ll b/llvm/test/CodeGen/X86/xaluo.ll index 9155350e65d..25fd21d80c6 100644 --- a/llvm/test/CodeGen/X86/xaluo.ll +++ b/llvm/test/CodeGen/X86/xaluo.ll @@ -1345,7 +1345,7 @@ define {i64, i1} @uaddoovf(i64 %a, i64 %b) { ; SDAG-NEXT: movzbl %dil, %ecx ; SDAG-NEXT: movzbl %sil, %eax ; SDAG-NEXT: addq %rcx, %rax -; SDAG-NEXT: setb %dl +; SDAG-NEXT: xorl %edx, %edx ; SDAG-NEXT: retq ; ; FAST-LABEL: uaddoovf: @@ -1353,7 +1353,7 @@ define {i64, i1} @uaddoovf(i64 %a, i64 %b) { ; FAST-NEXT: movzbl %dil, %ecx ; FAST-NEXT: movzbl %sil, %eax ; FAST-NEXT: addq %rcx, %rax -; FAST-NEXT: setb %dl +; FAST-NEXT: xorl %edx, %edx ; FAST-NEXT: retq ; ; KNL-LABEL: uaddoovf: @@ -1361,7 +1361,7 @@ define {i64, i1} @uaddoovf(i64 %a, i64 %b) { ; KNL-NEXT: movzbl %dil, %ecx ; KNL-NEXT: movzbl %sil, %eax ; KNL-NEXT: addq %rcx, %rax -; KNL-NEXT: setb %dl +; KNL-NEXT: xorl %edx, %edx ; KNL-NEXT: retq %1 = and i64 %a, 255 %2 = and i64 %b, 255 |
