From 5e5abb77fe9eeb92a55f119fdb721bca4508094a Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 11 Sep 2009 00:34:46 +0000
Subject: [PATCH] Reapply r81171 with a fix: don't try to use i64 when it isn't
 legal.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81492 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/FastISel.cpp | 23 +++++++++++++++++++----
 test/CodeGen/X86/fast-isel-fneg.ll    |  7 ++++---
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index f0c70861843..15c2140b86c 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -615,12 +615,27 @@ FastISel::SelectFNeg(User *I) {
   unsigned OpReg = getRegForValue(BinaryOperator::getFNegArgument(I));
   if (OpReg == 0) return false;
 
-  // Twiddle the sign bit with xor.
+  // Bitcast the value to integer, twiddle the sign bit with xor,
+  // and then bitcast it back to floating-point.
   EVT VT = TLI.getValueType(I->getType());
   if (VT.getSizeInBits() > 64) return false;
-  unsigned ResultReg = FastEmit_ri_(VT.getSimpleVT(), ISD::XOR, OpReg,
-                                    UINT64_C(1) << (VT.getSizeInBits()-1),
-                                    VT.getSimpleVT());
+  EVT IntVT = EVT::getIntegerVT(I->getContext(), VT.getSizeInBits());
+  if (!TLI.isTypeLegal(IntVT))
+    return false;
+
+  unsigned IntReg = FastEmit_r(VT.getSimpleVT(), IntVT.getSimpleVT(),
+                               ISD::BIT_CONVERT, OpReg);
+  if (IntReg == 0)
+    return false;
+
+  unsigned IntResultReg = FastEmit_ri_(IntVT.getSimpleVT(), ISD::XOR, IntReg,
+                                       UINT64_C(1) << (VT.getSizeInBits()-1),
+                                       IntVT.getSimpleVT());
+  if (IntResultReg == 0)
+    return false;
+
+  ResultReg = FastEmit_r(IntVT.getSimpleVT(), VT.getSimpleVT(),
+                         ISD::BIT_CONVERT, IntResultReg);
   if (ResultReg == 0)
     return false;
 
diff --git a/test/CodeGen/X86/fast-isel-fneg.ll b/test/CodeGen/X86/fast-isel-fneg.ll
index 15d4772927d..cc0f3de4f76 100644
--- a/test/CodeGen/X86/fast-isel-fneg.ll
+++ b/test/CodeGen/X86/fast-isel-fneg.ll
@@ -1,14 +1,15 @@
-; RUN: llc < %s -fast-isel -march=x86-64 | FileCheck %s
+; RUN: llc < %s -fast-isel -fast-isel-abort -march=x86-64 | FileCheck %s
+; RUN: llc < %s -fast-isel -march=x86 | grep xor | count 2
 
 ; CHECK: doo:
-; CHECK: xorpd
+; CHECK: xor
 define double @doo(double %x) nounwind {
   %y = fsub double -0.0, %x
   ret double %y
 }
 
 ; CHECK: foo:
-; CHECK: xorps
+; CHECK: xor
 define float @foo(float %x) nounwind {
   %y = fsub float -0.0, %x
   ret float %y