From 50df36ac0a7131b9208c26b8031066cd5b4b69ed Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 28 Aug 2010 03:36:51 +0000
Subject: for completeness, allow undef also.

llvm-svn: 112351
---
 llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'llvm/lib')

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 0434d6ba0fd..6c2477d52c7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1381,6 +1381,9 @@ static unsigned getTypeSizeIndex(unsigned Value, const Type *Ty) {
 static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
                                      SmallVectorImpl<Value*> &Elements,
                                      const Type *VecEltTy) {
+  // Undef values never contribute useful bits to the result.
+  if (isa<UndefValue>(V)) return true;
+  
   // If we got down to a value of the right type, we win, try inserting into the
   // right element.
   if (V->getType() == VecEltTy) {
-- 
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