From c2104d485690e1ef44717fbb3a74f75b91edad38 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Sat, 13 Sep 2014 21:46:00 +0000
Subject: [PATCH] Add control of function merging to the PMBuilder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217731 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Transforms/IPO/PassManagerBuilder.h |  1 +
 lib/Transforms/IPO/PassManagerBuilder.cpp        | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/llvm/Transforms/IPO/PassManagerBuilder.h b/include/llvm/Transforms/IPO/PassManagerBuilder.h
index 0cf346acebb..b1426b4f45c 100644
--- a/include/llvm/Transforms/IPO/PassManagerBuilder.h
+++ b/include/llvm/Transforms/IPO/PassManagerBuilder.h
@@ -123,6 +123,7 @@ public:
   bool VerifyInput;
   bool VerifyOutput;
   bool StripDebug;
+  bool MergeFunctions;
 
 private:
   /// ExtensionList - This is list of all of the extensions that are registered.
diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp
index 1b9d8c16060..d02e6975a19 100644
--- a/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -91,6 +91,7 @@ PassManagerBuilder::PassManagerBuilder() {
     VerifyInput = false;
     VerifyOutput = false;
     StripDebug = false;
+    MergeFunctions = false;
 }
 
 PassManagerBuilder::~PassManagerBuilder() {
@@ -330,6 +331,10 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
       MPM.add(createConstantMergePass());     // Merge dup global constants
     }
   }
+
+  if (MergeFunctions)
+    MPM.add(createMergeFunctionsPass());
+
   addExtensionsToPM(EP_OptimizerLast, MPM);
 }
 
@@ -427,6 +432,11 @@ void PassManagerBuilder::addLTOOptimizationPasses(PassManagerBase &PM) {
 
   // Now that we have optimized the program, discard unreachable functions.
   PM.add(createGlobalDCEPass());
+
+  // FIXME: this is profitable (for compiler time) to do at -O0 too, but
+  // currently it damages debug info.
+  if (MergeFunctions)
+    PM.add(createMergeFunctionsPass());
 }
 
 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,