From 60b3e18d674489364b6448d376ff6666f106c1fc Mon Sep 17 00:00:00 2001
From: Elena Demikhovsky <elena.demikhovsky@intel.com>
Date: Thu, 14 Feb 2013 08:20:26 +0000
Subject: [PATCH] Fixed a bug in X86TargetLowering::LowerVectorIntExtend()
 (assertion failure). Added a test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175144 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp           | 20 +++++++++++++++++---
 test/CodeGen/X86/2013-02-12-ShuffleToZext.ll | 14 ++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGen/X86/2013-02-12-ShuffleToZext.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 55de3d3c98a..dbc0e016f85 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6662,9 +6662,10 @@ X86TargetLowering::LowerVectorIntExtend(SDValue Op, SelectionDAG &DAG) const {
       return SDValue();
   }
 
+  LLVMContext *Context = DAG.getContext();
   unsigned NBits = VT.getVectorElementType().getSizeInBits() << Shift;
-  EVT NeVT = EVT::getIntegerVT(*DAG.getContext(), NBits);
-  EVT NVT = EVT::getVectorVT(*DAG.getContext(), NeVT, NumElems >> Shift);
+  EVT NeVT = EVT::getIntegerVT(*Context, NBits);
+  EVT NVT = EVT::getVectorVT(*Context, NeVT, NumElems >> Shift);
 
   if (!isTypeLegal(NVT))
     return SDValue();
@@ -6683,8 +6684,21 @@ X86TargetLowering::LowerVectorIntExtend(SDValue Op, SelectionDAG &DAG) const {
     // If it's foldable, i.e. normal load with single use, we will let code
     // selection to fold it. Otherwise, we will short the conversion sequence.
     if (CIdx && CIdx->getZExtValue() == 0 &&
-        (!ISD::isNormalLoad(V.getNode()) || !V.hasOneUse()))
+        (!ISD::isNormalLoad(V.getNode()) || !V.hasOneUse())) {
+      if (V.getValueSizeInBits() > V1.getValueSizeInBits()) {
+        // The "ext_vec_elt" node is wider than the result node.
+        // In this case we should extract subvector from V.
+        // (bitcast (sclr2vec (ext_vec_elt x))) -> (bitcast (extract_subvector x)).
+        unsigned Ratio = V.getValueSizeInBits() / V1.getValueSizeInBits();
+        EVT FullVT = V.getValueType();
+        EVT SubVecVT = EVT::getVectorVT(*Context, 
+                                        FullVT.getVectorElementType(),
+                                        FullVT.getVectorNumElements()/Ratio);
+        V = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, SubVecVT, V, 
+                        DAG.getIntPtrConstant(0));
+      }
       V1 = DAG.getNode(ISD::BITCAST, DL, V1.getValueType(), V);
+    }
   }
 
   return DAG.getNode(ISD::BITCAST, DL, VT,
diff --git a/test/CodeGen/X86/2013-02-12-ShuffleToZext.ll b/test/CodeGen/X86/2013-02-12-ShuffleToZext.ll
new file mode 100644
index 00000000000..614ccda5e25
--- /dev/null
+++ b/test/CodeGen/X86/2013-02-12-ShuffleToZext.ll
@@ -0,0 +1,14 @@
+; RUN: llc < %s -march=x86-64 -mcpu=corei7-avx -mtriple=x86_64-pc-win32 | FileCheck %s
+
+; CHECK: test
+; CHECK: vpmovzxwd
+; CHECK: vpmovzxwd
+define void @test(<4 x i64> %a, <4 x i16>* %buf) {
+  %ex1 = extractelement <4 x i64> %a, i32 0
+  %ex2 = extractelement <4 x i64> %a, i32 1
+  %x1 = bitcast i64 %ex1 to <4 x i16>
+  %x2 = bitcast i64 %ex2 to <4 x i16>
+  %Sh = shufflevector <4 x i16> %x1, <4 x i16> %x2, <4 x i32> <i32 0, i32 1, i32 4, i32 5>
+  store <4 x i16> %Sh, <4 x i16>* %buf, align 1
+  ret void
+}