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'.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150792 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CodeGenModule.cpp

@@ -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();
   }
   

test/CodeGenCXX/const-init-cxx11.cpp

@@ -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();
 }