From c752064894630565bdef503f6001e849a1fcfc3f Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 12 Aug 2009 00:32:55 +0000
Subject: [PATCH] Simplify this code, and use an in-bounds GEP.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78755 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/VMCore/ConstantFold.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index da9b6aa9784..e30f144658f 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -103,26 +103,28 @@ static Constant *FoldBitCast(LLVMContext &Context,
     if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy))
       if (PTy->getAddressSpace() == DPTy->getAddressSpace()) {
         SmallVector<Value*, 8> IdxList;
-        IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
+        Value *Zero = Constant::getNullValue(Type::Int32Ty);
+        IdxList.push_back(Zero);
         const Type *ElTy = PTy->getElementType();
         while (ElTy != DPTy->getElementType()) {
           if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
             if (STy->getNumElements() == 0) break;
             ElTy = STy->getElementType(0);
-            IdxList.push_back(Constant::getNullValue(Type::Int32Ty));
+            IdxList.push_back(Zero);
           } else if (const SequentialType *STy = 
                      dyn_cast<SequentialType>(ElTy)) {
             if (isa<PointerType>(ElTy)) break;  // Can't index into pointers!
             ElTy = STy->getElementType();
-            IdxList.push_back(IdxList[0]);
+            IdxList.push_back(Zero);
           } else {
             break;
           }
         }
         
         if (ElTy == DPTy->getElementType())
-          return ConstantExpr::getGetElementPtr(V, &IdxList[0],
-                                                      IdxList.size());
+          // This GEP is inbounds because all indices are zero.
+          return ConstantExpr::getInBoundsGetElementPtr(V, &IdxList[0],
+                                                        IdxList.size());
       }
   
   // Handle casts from one vector constant to another.  We know that the src