1 files changed, 40 insertions, 25 deletions

diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index b33ced8..117d273 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1162,12 +1162,9 @@ SDNode *X86DAGToDAGISel::Select(SDOperand N) {
       return NULL;
     }
       
-    case ISD::SDIV:
-    case ISD::UDIV:
-    case ISD::SREM:
-    case ISD::UREM: {
-      bool isSigned = Opcode == ISD::SDIV || Opcode == ISD::SREM;
-      bool isDiv    = Opcode == ISD::SDIV || Opcode == ISD::UDIV;
+    case X86ISD::DIV:
+    case X86ISD::IDIV: {
+      bool isSigned = Opcode == X86ISD::IDIV;
       if (!isSigned)
         switch (NVT) {
         default: assert(0 && "Unsupported VT!");
@@ -1275,31 +1272,49 @@ SDNode *X86DAGToDAGISel::Select(SDOperand N) {
           SDOperand(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0);
       }
 
-      unsigned Reg = isDiv ? LoReg : HiReg;
-      SDOperand Result;
-      if (Reg == X86::AH && Subtarget->is64Bit()) {
-        // Prevent use of AH in a REX instruction by referencing AX instead.
-        // Shift it down 8 bits.
-        Result = CurDAG->getCopyFromReg(Chain, X86::AX, MVT::i16, InFlag);
-        Chain = Result.getValue(1);
-        Result = SDOperand(CurDAG->getTargetNode(X86::SHR16ri, MVT::i16, Result,
-                                     CurDAG->getTargetConstant(8, MVT::i8)), 0);
-        // Then truncate it down to i8.
-        SDOperand SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1
-        Result = SDOperand(CurDAG->getTargetNode(X86::EXTRACT_SUBREG,
-                                                 MVT::i8, Result, SRIdx), 0);
-      } else {
-        Result = CurDAG->getCopyFromReg(Chain, Reg, NVT, InFlag);
+      // Copy the division (low) result, if it is needed.
+      if (!N.getValue(0).use_empty()) {
+        SDOperand Result = CurDAG->getCopyFromReg(Chain, LoReg, NVT, InFlag);
         Chain = Result.getValue(1);
+        InFlag = Result.getValue(2);
+        ReplaceUses(N.getValue(0), Result);
+#ifndef NDEBUG
+        DOUT << std::string(Indent-2, ' ') << "=> ";
+        DEBUG(Result.Val->dump(CurDAG));
+        DOUT << "\n";
+#endif
+      }
+      // Copy the remainder (high) result, if it is needed.
+      if (!N.getValue(1).use_empty()) {
+        SDOperand Result;
+        if (HiReg == X86::AH && Subtarget->is64Bit()) {
+          // Prevent use of AH in a REX instruction by referencing AX instead.
+          // Shift it down 8 bits.
+          Result = CurDAG->getCopyFromReg(Chain, X86::AX, MVT::i16, InFlag);
+          Chain = Result.getValue(1);
+          InFlag = Result.getValue(2);
+          Result = SDOperand(CurDAG->getTargetNode(X86::SHR16ri, MVT::i16, Result,
+                                       CurDAG->getTargetConstant(8, MVT::i8)), 0);
+          // Then truncate it down to i8.
+          SDOperand SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1
+          Result = SDOperand(CurDAG->getTargetNode(X86::EXTRACT_SUBREG,
+                                                   MVT::i8, Result, SRIdx), 0);
+        } else {
+          Result = CurDAG->getCopyFromReg(Chain, HiReg, NVT, InFlag);
+          Chain = Result.getValue(1);
+          InFlag = Result.getValue(2);
+        }
+        ReplaceUses(N.getValue(1), Result);
+#ifndef NDEBUG
+        DOUT << std::string(Indent-2, ' ') << "=> ";
+        DEBUG(Result.Val->dump(CurDAG));
+        DOUT << "\n";
+#endif
       }
-      ReplaceUses(N.getValue(0), Result);
       if (foldedLoad)
         ReplaceUses(N1.getValue(1), Chain);
 
 #ifndef NDEBUG
-      DOUT << std::string(Indent-2, ' ') << "=> ";
-      DEBUG(Result.Val->dump(CurDAG));
-      DOUT << "\n";
       Indent -= 2;
 #endif