From 8267be29955e3df2baada1443a92d82ca9d979cc Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@intel.com>
Date: Thu, 5 Dec 2019 17:47:33 -0800
Subject: [PATCH] [X86] Make X86TargetLowering::BuildFILD return a std::pair of
 SDValues so we explicitly return the chain instead of calling getValue on the
 single SDValue.

We shouldn't assume that the returned result can be used to get
the other result.

This is prep-work for strict FP where we will also need to pass
the chain result along in more cases.
---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 18 +++++++++---------
 llvm/lib/Target/X86/X86ISelLowering.h   |  5 +++--
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index a50d30f..4dc2ff4 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -18557,10 +18557,10 @@ SDValue X86TargetLowering::LowerSINT_TO_FP(SDValue Op,
   SDValue Chain = DAG.getStore(
       DAG.getEntryNode(), dl, ValueToStore, StackSlot,
       MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), SSFI));
-  return BuildFILD(Op, SrcVT, Chain, StackSlot, DAG);
+  return BuildFILD(Op, SrcVT, Chain, StackSlot, DAG).first;
 }
 
-SDValue X86TargetLowering::BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain,
+std::pair<SDValue, SDValue> X86TargetLowering::BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain,
                                      SDValue StackSlot,
                                      SelectionDAG &DAG) const {
   // Build the FILD
@@ -18589,9 +18589,9 @@ SDValue X86TargetLowering::BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain,
   SDValue Result =
       DAG.getMemIntrinsicNode(useSSE ? X86ISD::FILD_FLAG : X86ISD::FILD, DL,
                               Tys, FILDOps, SrcVT, LoadMMO);
+  Chain = Result.getValue(1);
 
   if (useSSE) {
-    Chain = Result.getValue(1);
     SDValue InFlag = Result.getValue(2);
 
     // FIXME: Currently the FST is glued to the FILD_FLAG. This
@@ -18613,9 +18613,10 @@ SDValue X86TargetLowering::BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain,
     Result = DAG.getLoad(
         Op.getValueType(), DL, Chain, StackSlot,
         MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), SSFI));
+    Chain = Result.getValue(1);
   }
 
-  return Result;
+  return { Result, Chain };
 }
 
 /// Horizontal vector math instructions may be slower than normal math with
@@ -18927,8 +18928,7 @@ SDValue X86TargetLowering::LowerUINT_TO_FP(SDValue Op,
                                   StackSlot, MachinePointerInfo());
     SDValue Store2 = DAG.getStore(Store1, dl, DAG.getConstant(0, dl, MVT::i32),
                                   OffsetSlot, MachinePointerInfo());
-    SDValue Fild = BuildFILD(Op, MVT::i64, Store2, StackSlot, DAG);
-    return Fild;
+    return BuildFILD(Op, MVT::i64, Store2, StackSlot, DAG).first;
   }
 
   assert(SrcVT == MVT::i64 && "Unexpected type in UINT_TO_FP");
@@ -43480,10 +43480,10 @@ static SDValue combineSIntToFP(SDNode *N, SelectionDAG &DAG,
     if (Ld->isSimple() && !VT.isVector() &&
         ISD::isNON_EXTLoad(Op0.getNode()) && Op0.hasOneUse() &&
         !Subtarget.is64Bit() && LdVT == MVT::i64) {
-      SDValue FILDChain = Subtarget.getTargetLowering()->BuildFILD(
+      std::pair<SDValue, SDValue> Tmp = Subtarget.getTargetLowering()->BuildFILD(
           SDValue(N, 0), LdVT, Ld->getChain(), Op0, DAG);
-      DAG.ReplaceAllUsesOfValueWith(Op0.getValue(1), FILDChain.getValue(1));
-      return FILDChain;
+      DAG.ReplaceAllUsesOfValueWith(Op0.getValue(1), Tmp.second);
+      return Tmp.first;
     }
   }
 
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index 82f56f8..2bf4977 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1201,8 +1201,9 @@ namespace llvm {
     /// offset as appropriate.
     Value *getSafeStackPointerLocation(IRBuilder<> &IRB) const override;
 
-    SDValue BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain, SDValue StackSlot,
-                      SelectionDAG &DAG) const;
+    std::pair<SDValue, SDValue> BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain,
+                                          SDValue StackSlot,
+                                          SelectionDAG &DAG) const;
 
     bool isNoopAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override;
 
-- 
2.7.4