Cleanup PPC(64) i32 -> float/double conversion

The existing SINT_TO_FP code for i32 -> float/double conversion was disabled
because it relied on broken EXTSW_32/STD_32 instruction definitions. The
original intent had been to enable these 64-bit instructions to be used on CPUs
that support them even in 32-bit mode.  Unfortunately, this form of lying to
the infrastructure was buggy (as explained in the FIXME comment) and had
therefore been disabled.

This re-enables this functionality, using regular DAG nodes, but only when
compiling in 64-bit mode. The old STD_32/EXTSW_32 definitions (which were dead)
are removed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178438 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 0574f04..bf31029 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -326,10 +326,8 @@
     // We cannot do this with Promote because i64 is not a legal type.
     setOperationAction(ISD::FP_TO_UINT, MVT::i32, Custom);
 
-    // FIXME: disable this lowered code.  This generates 64-bit register values,
-    // and we don't model the fact that the top part is clobbered by calls.  We
-    // need to flag these together so that the value isn't live across a call.
-    //setOperationAction(ISD::SINT_TO_FP, MVT::i32, Custom);
+    if (Subtarget->isPPC64())
+      setOperationAction(ISD::SINT_TO_FP, MVT::i32, Custom);
   } else {
     // PowerPC does not have FP_TO_UINT on 32-bit implementations.
     setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
@@ -592,8 +590,6 @@
   case PPCISD::SRL:             return "PPCISD::SRL";
   case PPCISD::SRA:             return "PPCISD::SRA";
   case PPCISD::SHL:             return "PPCISD::SHL";
-  case PPCISD::EXTSW_32:        return "PPCISD::EXTSW_32";
-  case PPCISD::STD_32:          return "PPCISD::STD_32";
   case PPCISD::CALL:            return "PPCISD::CALL";
   case PPCISD::CALL_NOP:        return "PPCISD::CALL_NOP";
   case PPCISD::MTCTR:           return "PPCISD::MTCTR";
@@ -4817,17 +4813,13 @@
   EVT PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
   SDValue FIdx = DAG.getFrameIndex(FrameIdx, PtrVT);
 
-  SDValue Ext64 = DAG.getNode(PPCISD::EXTSW_32, dl, MVT::i32,
-                                Op.getOperand(0));
+  SDValue Ext64 = DAG.getNode(ISD::SIGN_EXTEND, dl, MVT::i64,
+                              Op.getOperand(0));
 
   // STD the extended value into the stack slot.
-  MachineMemOperand *MMO =
-    MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx),
-                            MachineMemOperand::MOStore, 8, 8);
-  SDValue Ops[] = { DAG.getEntryNode(), Ext64, FIdx };
-  SDValue Store =
-    DAG.getMemIntrinsicNode(PPCISD::STD_32, dl, DAG.getVTList(MVT::Other),
-                            Ops, 4, MVT::i64, MMO);
+  SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Ext64, FIdx,
+                               MachinePointerInfo(), false, false, 0);
+
   // Load the value as a double.
   SDValue Ld = DAG.getLoad(MVT::f64, dl, Store, FIdx, MachinePointerInfo(),
                            false, false, false, 0);