Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -2643,6 +2643,11 @@
 
   maybeSetTrivialComdat(*D, *Fn);
 
+  // Create the attribute set of the function definition because it might differ
+  // from that of the function declaration. SetLLVMFunctionAttributes cannot be
+  // called after GenerateCode is called as it might remove the parameter
+  // attributes attached by GenerateCode.
+  SetLLVMFunctionAttributes(D, FI, Fn);
   CodeGenFunction(*this).GenerateCode(D, Fn, FI);
 
   setFunctionDefinitionAttributes(D, Fn);
Index: test/CodeGen/attr-func-def.c
===================================================================
--- /dev/null
+++ test/CodeGen/attr-func-def.c
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.10.0 -emit-llvm -Oz -o - %s | FileCheck %s
+
+// CHECK: define i32 @foo2(i32 %a) [[ATTRS2:#[0-9]+]] {
+// CHECK: define i32 @foo1(i32 %a) [[ATTRS1:#[0-9]+]] {
+
+int foo1(int);
+
+int foo2(int a) {
+  return foo1(a + 2);
+}
+
+__attribute__((optnone))
+int foo1(int a) {
+    return a + 1;
+}
+
+// CHECK: attributes [[ATTRS2]] = { {{.*}}optsize{{.*}} }
+// CHECK: attributes [[ATTRS1]] = { {{.*}}optnone{{.*}} }