From b7454fd9df0b477e3daf2fce6e1d5e1b241562df Mon Sep 17 00:00:00 2001
From: Jay Foad <jay.foad@gmail.com>
Date: Sat, 12 May 2012 08:30:16 +0000
Subject: [PATCH] Teach Function::hasAddressTaken that BlockAddress doesn't
 really take the address of a function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156703 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Function.h                          |  4 ++--
 lib/Transforms/IPO/GlobalOpt.cpp                 |  4 ++++
 lib/VMCore/Function.cpp                          |  3 ++-
 .../GlobalOpt/2012-05-11-blockaddress.ll         | 16 ++++++++++++++++
 4 files changed, 24 insertions(+), 3 deletions(-)
 create mode 100644 test/Transforms/GlobalOpt/2012-05-11-blockaddress.ll

diff --git a/include/llvm/Function.h b/include/llvm/Function.h
index e17cd87fe34..fdd90d1d8fa 100644
--- a/include/llvm/Function.h
+++ b/include/llvm/Function.h
@@ -420,8 +420,8 @@ public:
   void dropAllReferences();
 
   /// hasAddressTaken - returns true if there are any uses of this function
-  /// other than direct calls or invokes to it. Optionally passes back the
-  /// offending user for diagnostic purposes.
+  /// other than direct calls or invokes to it, or blockaddress expressions.
+  /// Optionally passes back an offending user for diagnostic purposes.
   ///
   bool hasAddressTaken(const User** = 0) const;
 
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 1522aa408b6..d316d526785 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1870,6 +1870,8 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV,
 /// function, changing them to FastCC.
 static void ChangeCalleesToFastCall(Function *F) {
   for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); UI != E;++UI){
+    if (isa<BlockAddress>(*UI))
+      continue;
     CallSite User(cast<Instruction>(*UI));
     User.setCallingConv(CallingConv::Fast);
   }
@@ -1890,6 +1892,8 @@ static AttrListPtr StripNest(const AttrListPtr &Attrs) {
 static void RemoveNestAttribute(Function *F) {
   F->setAttributes(StripNest(F->getAttributes()));
   for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); UI != E;++UI){
+    if (isa<BlockAddress>(*UI))
+      continue;
     CallSite User(cast<Instruction>(*UI));
     User.setAttributes(StripNest(User.getAttributes()));
   }
diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index af6344ef616..9b098a25250 100644
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -400,7 +400,8 @@ Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
 bool Function::hasAddressTaken(const User* *PutOffender) const {
   for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
     const User *U = *I;
-    // FIXME: Check for blockaddress, which does not take the address.
+    if (isa<BlockAddress>(U))
+      continue;
     if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
       return PutOffender ? (*PutOffender = U, true) : true;
     ImmutableCallSite CS(cast<Instruction>(U));
diff --git a/test/Transforms/GlobalOpt/2012-05-11-blockaddress.ll b/test/Transforms/GlobalOpt/2012-05-11-blockaddress.ll
new file mode 100644
index 00000000000..0c58c1a9d9c
--- /dev/null
+++ b/test/Transforms/GlobalOpt/2012-05-11-blockaddress.ll
@@ -0,0 +1,16 @@
+; RUN: opt < %s -globalopt -S | FileCheck %s
+; Check that the mere presence of a blockaddress doesn't prevent -globalopt
+; from promoting @f to fastcc.
+
+; CHECK: define{{.*}}fastcc{{.*}}@f
+define internal i8* @f() {
+  ret i8* blockaddress(@f, %L1)
+L1:
+  ret i8* null
+}
+
+define void @g() {
+  ; CHECK: call{{.*}}fastcc{{.*}}@f
+  %p = call i8* @f()
+  ret void
+}
-- 
2.34.1