Cleanup Darwin MMX calling conv stuff - make the stuff more generic. This also fixes a subtle bug, when 6th v1i64 argument passed wrongly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77963 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index b151349..ef387bb 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1429,24 +1429,10 @@
         RC = X86::FR64RegisterClass;
       else if (RegVT.isVector() && RegVT.getSizeInBits() == 128)
         RC = X86::VR128RegisterClass;
-      else if (RegVT.isVector()) {
-        assert(RegVT.getSizeInBits() == 64);
-        if (!Is64Bit)
-          RC = X86::VR64RegisterClass;     // MMX values are passed in MMXs.
-        else {
-          // Darwin calling convention passes MMX values in either GPRs or
-          // XMMs in x86-64. Other targets pass them in memory.
-          if (RegVT != MVT::v1i64 && Subtarget->hasSSE2()) {
-            RC = X86::VR128RegisterClass;  // MMX values are passed in XMMs.
-            RegVT = MVT::v2i64;
-          } else {
-            RC = X86::GR64RegisterClass;   // v1i64 values are passed in GPRs.
-            RegVT = MVT::i64;
-          }
-        }
-      } else {
+      else if (RegVT.isVector() && RegVT.getSizeInBits() == 64)
+        RC = X86::VR64RegisterClass;
+      else
         llvm_unreachable("Unknown argument type!");
-      }
 
       unsigned Reg = MF.addLiveIn(VA.getLocReg(), RC);
       SDValue ArgValue = DAG.getCopyFromReg(Root, dl, Reg, RegVT);
@@ -1460,19 +1446,19 @@
       else if (VA.getLocInfo() == CCValAssign::ZExt)
         ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
                                DAG.getValueType(VA.getValVT()));
+      else if (VA.getLocInfo() == CCValAssign::BCvt)
+        ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, RegVT, ArgValue,
+                               DAG.getValueType(VA.getValVT()));
 
-      if (VA.getLocInfo() != CCValAssign::Full)
-        ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
-
-      // Handle MMX values passed in GPRs.
-      if (Is64Bit && RegVT != VA.getLocVT()) {
-        if (RegVT.getSizeInBits() == 64 && RC == X86::GR64RegisterClass)
-          ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getLocVT(), ArgValue);
-        else if (RC == X86::VR128RegisterClass) {
+      if (VA.getLocInfo() != CCValAssign::Full &&
+          VA.getLocInfo() != CCValAssign::BCvt) {
+        // Handle MMX values passed in XMM regs.
+        if (RegVT.isVector()) {
           ArgValue = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i64,
                                  ArgValue, DAG.getConstant(0, MVT::i64));
-          ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getLocVT(), ArgValue);
-        }
+          ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getValVT(), ArgValue);
+        } else
+          ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
       }
 
       ArgValues.push_back(ArgValue);
@@ -1734,6 +1720,7 @@
   // of tail call optimization arguments are handle later.
   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
     CCValAssign &VA = ArgLocs[i];
+    MVT RegVT = VA.getLocVT();
     SDValue Arg = TheCall->getArg(i);
     ISD::ArgFlagsTy Flags = TheCall->getArgFlags(i);
     bool isByVal = Flags.isByVal();
@@ -1743,39 +1730,26 @@
     default: llvm_unreachable("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::SExt:
-      Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
+      Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, RegVT, Arg);
       break;
     case CCValAssign::ZExt:
-      Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
+      Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, RegVT, Arg);
       break;
     case CCValAssign::AExt:
-      Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
+      if (RegVT.isVector() && RegVT.getSizeInBits() == 128) {
+        // Special case: passing MMX values in XMM registers.
+        Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i64, Arg);
+        Arg = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v2i64, Arg);
+        Arg = getMOVL(DAG, dl, MVT::v2i64, DAG.getUNDEF(MVT::v2i64), Arg);
+      } else
+        Arg = DAG.getNode(ISD::ANY_EXTEND, dl, RegVT, Arg);
+      break;
+    case CCValAssign::BCvt:
+      Arg = DAG.getNode(ISD::BIT_CONVERT, dl, RegVT, Arg);
       break;
     }
 
     if (VA.isRegLoc()) {
-      if (Is64Bit) {
-        MVT RegVT = VA.getLocVT();
-        if (RegVT.isVector() && RegVT.getSizeInBits() == 64)
-          switch (VA.getLocReg()) {
-          default:
-            break;
-          case X86::RDI: case X86::RSI: case X86::RDX: case X86::RCX:
-          case X86::R8: {
-            // Special case: passing MMX values in GPR registers.
-            Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i64, Arg);
-            break;
-          }
-          case X86::XMM0: case X86::XMM1: case X86::XMM2: case X86::XMM3:
-          case X86::XMM4: case X86::XMM5: case X86::XMM6: case X86::XMM7: {
-            // Special case: passing MMX values in XMM registers.
-            Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i64, Arg);
-            Arg = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MVT::v2i64, Arg);
-            Arg = getMOVL(DAG, dl, MVT::v2i64, DAG.getUNDEF(MVT::v2i64), Arg);
-            break;
-          }
-          }
-      }
       RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
     } else {
       if (!IsTailCall || (IsTailCall && isByVal)) {