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When performing IRGen on a global, emit it as a constant if: 

1) It has a const-qualified type, and
 2) It has no mutable members, and
 3) It has no dynamic initialization, and
 4) It has trivial destruction.
Remove the unnecessary requirement that the type be POD. This allows us to
mark all constexpr objects with no mutable members as 'constant'.

llvm-svn: 150792
This commit is contained in:
Richard Smith 2012-02-17 04:54:50 +00:00
parent 7ae3c75d97
commit ae819500a1
2 changed files with 8 additions and 9 deletions
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1
clang/lib/CodeGen/CodeGenModule.cpp
View File

@ -1110,7 +1110,6 @@ static bool DeclIsConstantGlobal(ASTContext &Context, const VarDecl *D,
if (const RecordType *Record
= Context.getBaseElementType(D->getType())->getAs<RecordType>())
return ConstantInit &&
cast<CXXRecordDecl>(Record->getDecl())->isPOD() &&
!cast<CXXRecordDecl>(Record->getDecl())->hasMutableFields();
}

16
clang/test/CodeGenCXX/const-init-cxx11.cpp
View File

@ -16,10 +16,10 @@ namespace StructUnion {
constexpr A(int n, double d, const char *y) : n(n), d(d), u(y) {}
};
// CHECK: @_ZN11StructUnion1aE = global {{.*}} { i32 1, double 2.000000e+00, {{.*}} { i32 3, [4 x i8] undef } }
// CHECK: @_ZN11StructUnion1aE = constant {{.*}} { i32 1, double 2.000000e+00, {{.*}} { i32 3, [4 x i8] undef } }
extern constexpr A a(1, 2.0, 3);
// CHECK: @_ZN11StructUnion1bE = global {{.*}} { i32 4, double 5.000000e+00, {{.*}} { i8* getelementptr inbounds ([6 x i8]* @{{.*}}, i32 0, i32 0) } }
// CHECK: @_ZN11StructUnion1bE = constant {{.*}} { i32 4, double 5.000000e+00, {{.*}} { i8* getelementptr inbounds ([6 x i8]* @{{.*}}, i32 0, i32 0) } }
extern constexpr A b(4, 5, "hello");
struct B {
@ -62,21 +62,21 @@ namespace BaseClass {
struct Test : Ts... { constexpr Test() : Ts()..., n(5) {} int n; };
using Test1 = Test<N, C, Cs<1,2>, D, X<C,1>>;
// CHECK: @_ZN9BaseClass2t1E = global {{.*}} { i32 3, i8 1, i8 1, i8 1, double 4.000000e+00, i8 1, i32 5 }, align 8
// CHECK: @_ZN9BaseClass2t1E = constant {{.*}} { i32 3, i8 1, i8 1, i8 1, double 4.000000e+00, i8 1, i32 5 }, align 8
extern constexpr Test1 t1 = Test1();
struct DN : D, N {};
struct DND : DN, X<D,0> {};
struct DNN : DN, X<N,0> {};
// CHECK: @_ZN9BaseClass3dndE = global {{.*}} { double 4.000000e+00, i32 3, double 4.000000e+00 }
// CHECK: @_ZN9BaseClass3dndE = constant {{.*}} { double 4.000000e+00, i32 3, double 4.000000e+00 }
extern constexpr DND dnd = DND();
// Note, N subobject is laid out in DN subobject's tail padding.
// CHECK: @_ZN9BaseClass3dnnE = global {{.*}} { double 4.000000e+00, i32 3, i32 3 }
// CHECK: @_ZN9BaseClass3dnnE = constant {{.*}} { double 4.000000e+00, i32 3, i32 3 }
extern constexpr DNN dnn = DNN();
struct E {};
struct Test2 : X<E,0>, X<E,1>, X<E,2>, X<E,3> {};
// CHECK: @_ZN9BaseClass2t2E = global {{.*}} undef
// CHECK: @_ZN9BaseClass2t2E = constant {{.*}} undef
extern constexpr Test2 t2 = Test2();
}
@ -88,7 +88,7 @@ namespace Array {
extern constexpr char c[6][4] = { "foo", "a", { "bar" }, { 'x', 'y', 'z' }, { "b" }, '1', '2', '3' };
struct C { constexpr C() : n(5) {} int n, m = 3 * n + 1; };
// CHECK: @_ZN5Array5ctorsE = global [3 x {{.*}}] [{{.*}} { i32 5, i32 16 }, {{.*}} { i32 5, i32 16 }, {{.*}} { i32 5, i32 16 }]
// CHECK: @_ZN5Array5ctorsE = constant [3 x {{.*}}] [{{.*}} { i32 5, i32 16 }, {{.*}} { i32 5, i32 16 }, {{.*}} { i32 5, i32 16 }]
extern const C ctors[3];
constexpr C ctors[3];
@ -100,7 +100,7 @@ namespace Array {
char d[4];
constexpr E() : c("foo"), d("x") {}
};
// CHECK: @_ZN5Array1eE = global {{.*}} { [4 x i8] c"foo\00", [4 x i8] c"x\00\00\00" }
// CHECK: @_ZN5Array1eE = constant {{.*}} { [4 x i8] c"foo\00", [4 x i8] c"x\00\00\00" }
extern constexpr E e = E();
}