From 1e1a88e8cc6c51d0f00ecdbdbcf40bd23e124d27 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Thu, 20 Jul 2006 23:09:47 +0000
Subject: [PATCH] A splat of a vector constant of all zero or all one is the
 vector constant.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29234 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 4ebe4caad09..2ae607c182c 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2393,6 +2393,8 @@ X86TargetLowering::LowerVECTOR_SHUFFLE(SDOperand Op, SelectionDAG &DAG) {
   bool V2IsUndef = V2.getOpcode() == ISD::UNDEF;
 
   if (isSplatMask(PermMask.Val)) {
+    if (ISD::isBuildVectorAllZeros(V1.Val) || ISD::isBuildVectorAllOnes(V1.Val))
+      return V1;
     if (NumElems <= 4) return Op;
     // Promote it to a v4i32 splat.
     return PromoteSplat(Op, DAG);