Create a new attribute set when the definition is parsed after a declaration of a function

[ahatanak]

Summary

An assert is triggered when the test case program is compiled with -Oz:

Assertion failed: (!F->hasFnAttribute(llvm::Attribute::OptimizeForSize) && "OptimizeNone and OptimizeForSize on same function!"), function SetLLVMFunctionAttributesForDefinition, file /Users/ahatanaka/projects/llvm/git/llvm/tools/clang/lib/CodeGen/CodeGenModule.cpp, line 831.

This patch fixes the assert by clearing the attribute set attached to IR function foo1 and creating it again when the function's definition is parsed.

[vsk]

Thanks, LGTM.

cfe/trunk/lib/CodeGen/CodeGenModule.cpp

F->addAttributes(llvm::AttributeSet::FunctionIndex,
                        F->getContext(), llvm::AttributeSet::FunctionIndex, B));
 
   if (D->hasAttr<OptimizeNoneAttr>()) {
     // OptimizeNone implies noinline; we should not be inlining such functions.
     F->addFnAttr(llvm::Attribute::OptimizeNone);
     F->addFnAttr(llvm::Attribute::NoInline);
 
     // OptimizeNone wins over OptimizeForSize, MinSize, AlwaysInline.
-    assert(!F->hasFnAttribute(llvm::Attribute::OptimizeForSize) &&
-           "OptimizeNone and OptimizeForSize on same function!");
-    assert(!F->hasFnAttribute(llvm::Attribute::MinSize) &&
-           "OptimizeNone and MinSize on same function!");
+    F->removeFnAttr(llvm::Attribute::OptimizeForSize);
+    F->removeFnAttr(llvm::Attribute::MinSize);
     assert(!F->hasFnAttribute(llvm::Attribute::AlwaysInline) &&
            "OptimizeNone and AlwaysInline on same function!");
 
     // Attribute 'inlinehint' has no effect on 'optnone' functions.
     // Explicitly remove it from the set of function attributes.
     F->removeFnAttr(llvm::Attribute::InlineHint);
   }
 

cfe/trunk/test/CodeGen/attr-func-def.c

+// 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{{.*}} }