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

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 7c0c32251293047b3af2919a2d1b3ba87aaf5389..3a58afdc260970470738ad1280f6c9fe0dc8ac64 100644 (file)
--- 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;