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.

llvm-svn: 16876

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 7c0c3225129..3a58afdc260 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/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;