Target/X86: Fix assertion failures and warnings caused by r151382 _ftol2 lowering for i386-*-win32 targets. Patch by Joe Groff.

[Joe Groff] Hi everyone. My previous patch applied as r151382 had a few problems:
Clang raised a warning, and X86 LowerOperation would assert out for
fptoui f64 to i32 because it improperly lowered to an illegal
BUILD_PAIR. Here's a patch that addresses these issues. Let me know if
any other changes are necessary. Thanks.

llvm-svn: 151432

3 files changed, 20 insertions, 12 deletions

diff --git a/llvm/lib/Target/X86/X86FloatingPoint.cpp b/llvm/lib/Target/X86/X86FloatingPoint.cpp
index 5c003885419..32de194725c 100644
--- a/llvm/lib/Target/X86/X86FloatingPoint.cpp
+++ b/llvm/lib/Target/X86/X86FloatingPoint.cpp
@@ -1646,8 +1646,6 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
 
   case X86::WIN_FTOL_32:
   case X86::WIN_FTOL_64: {
-    MachineBasicBlock::iterator InsertPt = MI;
-
     // Push the operand into ST0.
     MachineOperand &Op = MI->getOperand(0);
     assert(Op.isUse() && Op.isReg() &&
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 8cb8fbb369a..c1ecbbb83c0 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -7712,7 +7712,7 @@ SDValue X86TargetLowering::LowerUINT_TO_FP(SDValue Op,
 }
 
 std::pair<SDValue,SDValue> X86TargetLowering::
-FP_TO_INTHelper(SDValue Op, SelectionDAG &DAG, bool IsSigned) const {
+FP_TO_INTHelper(SDValue Op, SelectionDAG &DAG, bool IsSigned, bool IsReplace) const {
   DebugLoc DL = Op.getDebugLoc();
 
   EVT DstTy = Op.getValueType();
@@ -7796,7 +7796,10 @@ FP_TO_INTHelper(SDValue Op, SelectionDAG &DAG, bool IsSigned) const {
       MVT::i32, ftol.getValue(1));
     SDValue edx = DAG.getCopyFromReg(eax.getValue(1), DL, X86::EDX,
       MVT::i32, eax.getValue(2));
-    SDValue pair = DAG.getNode(ISD::BUILD_PAIR, DL, MVT::i64, eax, edx);
+    SDValue Ops[] = { eax, edx };
+    SDValue pair = IsReplace
+      ? DAG.getNode(ISD::BUILD_PAIR, DL, MVT::i64, Ops, 2)
+      : DAG.getMergeValues(Ops, 2, DL);
     return std::make_pair(pair, SDValue());
   }
 }
@@ -7806,7 +7809,8 @@ SDValue X86TargetLowering::LowerFP_TO_SINT(SDValue Op,
   if (Op.getValueType().isVector())
     return SDValue();
 
-  std::pair<SDValue,SDValue> Vals = FP_TO_INTHelper(Op, DAG, true);
+  std::pair<SDValue,SDValue> Vals = FP_TO_INTHelper(Op, DAG,
+    /*IsSigned=*/ true, /*IsReplace=*/ false);
   SDValue FIST = Vals.first, StackSlot = Vals.second;
   // If FP_TO_INTHelper failed, the node is actually supposed to be Legal.
   if (FIST.getNode() == 0) return Op;
@@ -7823,14 +7827,19 @@ SDValue X86TargetLowering::LowerFP_TO_SINT(SDValue Op,
 
 SDValue X86TargetLowering::LowerFP_TO_UINT(SDValue Op,
                                            SelectionDAG &DAG) const {
-  std::pair<SDValue,SDValue> Vals = FP_TO_INTHelper(Op, DAG, false);
+  std::pair<SDValue,SDValue> Vals = FP_TO_INTHelper(Op, DAG,
+    /*IsSigned=*/ false, /*IsReplace=*/ false);
   SDValue FIST = Vals.first, StackSlot = Vals.second;
   assert(FIST.getNode() && "Unexpected failure");
 
-  // Load the result.
-  return DAG.getLoad(Op.getValueType(), Op.getDebugLoc(),
-                     FIST, StackSlot, MachinePointerInfo(),
-                     false, false, false, 0);
+  if (StackSlot.getNode())
+    // Load the result.
+    return DAG.getLoad(Op.getValueType(), Op.getDebugLoc(),
+                       FIST, StackSlot, MachinePointerInfo(),
+                       false, false, false, 0);
+  else
+    // The node is the result.
+    return FIST;
 }
 
 SDValue X86TargetLowering::LowerFABS(SDValue Op,
@@ -10872,7 +10881,7 @@ void X86TargetLowering::ReplaceNodeResults(SDNode *N,
       return;
 
     std::pair<SDValue,SDValue> Vals =
-        FP_TO_INTHelper(SDValue(N, 0), DAG, IsSigned);
+        FP_TO_INTHelper(SDValue(N, 0), DAG, IsSigned, /*IsReplace=*/ true);
     SDValue FIST = Vals.first, StackSlot = Vals.second;
     if (FIST.getNode() != 0) {
       EVT VT = N->getValueType(0);
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index 8b6cda5927b..1f5657d30f3 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -708,7 +708,8 @@ namespace llvm {
                                          SelectionDAG &DAG) const;
 
     std::pair<SDValue,SDValue> FP_TO_INTHelper(SDValue Op, SelectionDAG &DAG,
-                                               bool isSigned) const;
+                                               bool isSigned,
+                                               bool isReplace) const;
 
     SDValue LowerAsSplatVectorLoad(SDValue SrcOp, EVT VT, DebugLoc dl,
                                    SelectionDAG &DAG) const;