From 1c40e188c579c49f811eee499af2f371298c758c Mon Sep 17 00:00:00 2001
From: Mon P Wang <wangmp@apple.com>
Date: Thu, 18 Feb 2010 22:33:18 +0000
Subject: [PATCH] getSplatIndex assumes that the first element of the mask
 contains the splat index which is not always true if the mask contains
 undefs. Modified it to return the first non undef value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96621 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/SelectionDAGNodes.h |  7 ++++++-
 test/CodeGen/X86/vec_shuffle-36.ll       | 17 ++++++++++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index 9a426a04773..90669136204 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -1764,7 +1764,12 @@ public:
   bool isSplat() const { return isSplatMask(Mask, getValueType(0)); }
   int  getSplatIndex() const { 
     assert(isSplat() && "Cannot get splat index for non-splat!");
-    return Mask[0];
+    EVT VT = getValueType(0);
+    for (unsigned i = 0, e = VT.getVectorNumElements(); i != e; ++i) {
+      if (Mask[i] != -1)
+        return Mask[i];
+    }
+    return -1;
   }
   static bool isSplatMask(const int *Mask, EVT VT);
 
diff --git a/test/CodeGen/X86/vec_shuffle-36.ll b/test/CodeGen/X86/vec_shuffle-36.ll
index 8a93a7eeee3..1ea37c881e7 100644
--- a/test/CodeGen/X86/vec_shuffle-36.ll
+++ b/test/CodeGen/X86/vec_shuffle-36.ll
@@ -1,9 +1,16 @@
-; RUN: llc < %s -march=x86 -mattr=sse41 -o %t
-; RUN: grep pshufb %t | count 1
-
+; RUN: llc < %s -march=x86-64 -mattr=sse41 | FileCheck %s
 
 define <8 x i16> @shuf6(<8 x i16> %T0, <8 x i16> %T1) nounwind readnone {
+; CHECK: pshufb
+; CHECK-NOT: pshufb
+; CHECK: ret
 entry:
-	%tmp9 = shufflevector <8 x i16> %T0, <8 x i16> %T1, <8 x i32> < i32 3, i32 2, i32 0, i32 2, i32 1, i32 5, i32 6 , i32 undef >
-	ret <8 x i16> %tmp9
+  %tmp9 = shufflevector <8 x i16> %T0, <8 x i16> %T1, <8 x i32> < i32 3, i32 2, i32 0, i32 2, i32 1, i32 5, i32 6 , i32 undef >
+  ret <8 x i16> %tmp9
 }
+
+define <8 x i16> @shuf7(<8 x i16> %t0) {
+; CHECK: pshufd
+  %tmp10 = shufflevector <8 x i16> %t0, <8 x i16> undef, <8 x i32> < i32 undef, i32 2, i32 2, i32 2, i32 2, i32 2, i32 undef, i32 undef >
+  ret <8 x i16> %tmp10
+}
\ No newline at end of file
-- 
2.34.1