From 02137eec8f22363d5412b827162d1ae8356db28d Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 14 Apr 2007 01:11:54 +0000
Subject: [PATCH] in addition to merging, constantmerge should also delete
 trivially dead globals, in order to clean up after simplifylibcalls.

llvm-svn: 35982
---
 llvm/lib/Transforms/IPO/ConstantMerge.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/IPO/ConstantMerge.cpp b/llvm/lib/Transforms/IPO/ConstantMerge.cpp
index 11ec09ab2e62..fc142e16d22e 100644
--- a/llvm/lib/Transforms/IPO/ConstantMerge.cpp
+++ b/llvm/lib/Transforms/IPO/ConstantMerge.cpp
@@ -61,7 +61,13 @@ bool ConstantMerge::runOnModule(Module &M) {
     // invalidating the Constant* pointers in CMap.
     //
     for (Module::global_iterator GV = M.global_begin(), E = M.global_end();
-         GV != E; ++GV)
+         GV != E; ++GV) {
+      // If this GV is dead, remove it.
+      GV->removeDeadConstantUsers();
+      if (GV->use_empty() && GV->hasInternalLinkage()) {
+        (GV++)->eraseFromParent();
+      }
+      
       // Only process constants with initializers.
       if (GV->isConstant() && GV->hasInitializer()) {
         Constant *Init = GV->getInitializer();
@@ -80,6 +86,7 @@ bool ConstantMerge::runOnModule(Module &M) {
           Slot = GV;
         }
       }
+    }
 
     if (Replacements.empty())
       return MadeChange;