From c4d81b0388dff9f38e1387bb223cc7b514c06d01 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 10 Oct 2004 16:47:33 +0000
Subject: [PATCH] Implement GlobalOpt/deadglobal-2.llx, deletion of globals
 that are only stored to, but are stored at variable indexes.  This occurs at
 least in 176.gcc, but probably others, and we should handle it for
 completeness.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16876 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/GlobalOpt.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 7c0c3225129..3a58afdc260 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -259,6 +259,17 @@ static bool CleanupConstantGlobalUsers(Value *V, Constant *Init) {
     } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
       if (Constant *SubInit = TraverseGEPInitializer(GEP, Init))
         Changed |= CleanupConstantGlobalUsers(GEP, SubInit);
+      else {
+        // If this GEP has variable indexes, we should still be able to delete
+        // any stores through it.
+        for (Value::use_iterator GUI = GEP->use_begin(), E = GEP->use_end();
+             GUI != E;)
+          if (StoreInst *SI = dyn_cast<StoreInst>(*GUI++)) {
+            SI->getParent()->getInstList().erase(SI);
+            Changed = true;
+          }
+      }
+
       if (GEP->use_empty()) {
         GEP->getParent()->getInstList().erase(GEP);
         Changed = true;