From 84be958ed8db1ba2e0caca8964b7077761694f92 Mon Sep 17 00:00:00 2001
From: Stuart Hastings <stuart@apple.com>
Date: Thu, 2 Jun 2011 15:57:11 +0000
Subject: Omit unnecessary stack copy when x87 input is a load.
 rdar://problem/6373334

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132458 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp    | 23 +++++++++++++++++------
 test/CodeGen/X86/2011-06-01-fildll.ll | 15 +++++++++++++++
 2 files changed, 32 insertions(+), 6 deletions(-)
 create mode 100644 test/CodeGen/X86/2011-06-01-fildll.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index fe0af23ff9..4d9869634d 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6700,6 +6700,11 @@ SDValue X86TargetLowering::LowerSINT_TO_FP(SDValue Op,
   DebugLoc dl = Op.getDebugLoc();
   unsigned Size = SrcVT.getSizeInBits()/8;
   MachineFunction &MF = DAG.getMachineFunction();
+
+  SDValue Addr = Op.getOperand(0);
+  if (Addr.getOpcode() == ISD::LOAD)
+    return BuildFILD(Op, SrcVT, DAG.getEntryNode(), Addr, DAG);
+
   int SSFI = MF.getFrameInfo()->CreateStackObject(Size, Size, false);
   SDValue StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
   SDValue Chain = DAG.getStore(DAG.getEntryNode(), dl, Op.getOperand(0),
@@ -6723,12 +6728,18 @@ SDValue X86TargetLowering::BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain,
 
   unsigned ByteSize = SrcVT.getSizeInBits()/8;
 
-  int SSFI = cast<FrameIndexSDNode>(StackSlot)->getIndex();
-  MachineMemOperand *MMO =
-    DAG.getMachineFunction()
-    .getMachineMemOperand(MachinePointerInfo::getFixedStack(SSFI),
-                          MachineMemOperand::MOLoad, ByteSize, ByteSize);
-
+  FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(StackSlot);
+  MachineMemOperand *MMO;
+  if (FI) {
+    int SSFI = FI->getIndex();
+    MMO =
+      DAG.getMachineFunction()
+      .getMachineMemOperand(MachinePointerInfo::getFixedStack(SSFI),
+                            MachineMemOperand::MOLoad, ByteSize, ByteSize);
+  } else {
+    MMO = cast<LoadSDNode>(StackSlot)->getMemOperand();
+    StackSlot = StackSlot.getOperand(1);
+  }
   SDValue Ops[] = { Chain, StackSlot, DAG.getValueType(SrcVT) };
   SDValue Result = DAG.getMemIntrinsicNode(useSSE ? X86ISD::FILD_FLAG :
                                            X86ISD::FILD, DL,
diff --git a/test/CodeGen/X86/2011-06-01-fildll.ll b/test/CodeGen/X86/2011-06-01-fildll.ll
new file mode 100644
index 0000000000..35f8afaae0
--- /dev/null
+++ b/test/CodeGen/X86/2011-06-01-fildll.ll
@@ -0,0 +1,15 @@
+; RUN: llc %s -march=x86
+; ModuleID = '<stdin>'
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
+target triple = "i386-apple-macosx10.6.6"
+
+define float @f(i64* nocapture %x) nounwind readonly ssp {
+entry:
+; CHECK: movl
+; CHECK-NOT: movl
+  %tmp1 = load i64* %x, align 4
+; CHECK: fildll
+  %conv = sitofp i64 %tmp1 to float
+  %add = fadd float %conv, 1.000000e+00
+  ret float %add
+}
-- 
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