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

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 7c0c322512..3a58afdc26 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;