From 0ddf404cf4bd29ad9816c4b0f42783b6c15e112c Mon Sep 17 00:00:00 2001
From: Mehdi Amini <mehdi.amini@apple.com>
Date: Mon, 2 May 2016 18:03:33 +0000
Subject: [PATCH] ReversePostOrderFunctionAttrs is not modifying the call
 graph, let's preserve it.

When running cc1 with -flto=thin, it is followed by GlobalOpt, which
requires the callgraph. This saves rebuilding one.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 268266
---
 llvm/lib/Transforms/IPO/FunctionAttrs.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 91768f5..b6ebc63 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -1153,6 +1153,7 @@ struct ReversePostOrderFunctionAttrs : public ModulePass {
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesCFG();
     AU.addRequired<CallGraphWrapperPass>();
+    AU.addPreserved<CallGraphWrapperPass>();
   }
 };
 }
-- 
2.7.4