- if (HiReg == X86::AH && Subtarget->is64Bit() &&
- !SDValue(Node, 1).use_empty()) {
- SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
- X86::AX, MVT::i16, InFlag);
- InFlag = Result.getValue(2);
-
- // If we also need AL (the quotient), get it by extracting a subreg from
- // Result. The fast register allocator does not like multiple CopyFromReg
- // nodes using aliasing registers.
- if (!SDValue(Node, 0).use_empty())
- ReplaceUses(SDValue(Node, 0),
- CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
-
- // Shift AX right by 8 bits instead of using AH.
- Result = SDValue(CurDAG->getMachineNode(X86::SHR16ri, dl, MVT::i16,
- Result,
- CurDAG->getTargetConstant(8, MVT::i8)),
- 0);
- ReplaceUses(SDValue(Node, 1),
- CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
+ if (HiReg == X86::AH && !SDValue(Node, 1).use_empty()) {
+ SDValue AHCopy = CurDAG->getRegister(X86::AH, MVT::i8);
+ unsigned AHExtOpcode =
+ isSigned ? X86::MOVSX32_NOREXrr8 : X86::MOVZX32_NOREXrr8;
+
+ SDNode *RNode = CurDAG->getMachineNode(AHExtOpcode, dl, MVT::i32,
+ MVT::Glue, AHCopy, InFlag);
+ SDValue Result(RNode, 0);
+ InFlag = SDValue(RNode, 1);
+
+ if (Opcode == X86ISD::UDIVREM8_ZEXT_HREG ||
+ Opcode == X86ISD::SDIVREM8_SEXT_HREG) {
+ if (Node->getValueType(1) == MVT::i64) {
+ // It's not possible to directly movsx AH to a 64bit register, because
+ // the latter needs the REX prefix, but the former can't have it.
+ assert(Opcode != X86ISD::SDIVREM8_SEXT_HREG &&
+ "Unexpected i64 sext of h-register");
+ Result =
+ SDValue(CurDAG->getMachineNode(
+ TargetOpcode::SUBREG_TO_REG, dl, MVT::i64,
+ CurDAG->getTargetConstant(0, MVT::i64), Result,
+ CurDAG->getTargetConstant(X86::sub_32bit, MVT::i32)),
+ 0);
+ }
+ } else {
+ Result =
+ CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result);
+ }
+ ReplaceUses(SDValue(Node, 1), Result);
+ DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');