From: Pete Cooper <peter_cooper@apple.com>
Date: Thu, 10 Nov 2011 21:45:06 +0000 (+0000)
Subject: Add invariant.load metadata to loads from selector references.  Allows these loads... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b6d7114bcfa29b262f9f043a76da7dba39d65136;p=clang

Add invariant.load metadata to loads from selector references.  Allows these loads to later be moved/combined in the optimizer.  Fixes <rdar://problem/6027699>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@144318 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 84277f6827..1cbcc58ae5 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -5887,7 +5887,12 @@ llvm::Value *CGObjCNonFragileABIMac::EmitSelector(CGBuilderTy &Builder,
 
   if (lval)
     return Entry;
-  return Builder.CreateLoad(Entry);
+  llvm::LoadInst* LI = Builder.CreateLoad(Entry);
+  
+  LI->setMetadata(CGM.getModule().getMDKindID("invariant.load"), 
+                  llvm::MDNode::get(VMContext,
+                                    ArrayRef<llvm::Value*>()));
+  return LI;
 }
 /// EmitObjCIvarAssign - Code gen for assigning to a __strong object.
 /// objc_assign_ivar (id src, id *dst, ptrdiff_t)
diff --git a/test/CodeGenObjC/selector-ref-invariance.m b/test/CodeGenObjC/selector-ref-invariance.m
new file mode 100644
index 0000000000..e356419de9
--- /dev/null
+++ b/test/CodeGenObjC/selector-ref-invariance.m
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -emit-llvm -fblocks -o - %s | FileCheck %s
+
+// rdar://6027699
+
+void test(id x) {
+// CHECK: load i8** @"\01L_OBJC_SELECTOR_REFERENCES_", !invariant.load
+// CHECK: @objc_msgSend
+  [x foo];
+}