https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80228
Bernd Edlinger <edlinger at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords|diagnostic, rejects-valid |wrong-code
--- Comment #3 from Bernd Edlinger <edlinger at gcc dot gnu.org> ---
This is half fixed by r267653
B was already correctly rejected, and is invalid in C++11:
$ cat x.cc
struct A { int n, a[]; };
struct B
{
int n = 3;
int a1[] = { 2, 1, 0 }; // rejected (see pr72775)
} b;
struct C
{
A a2 = { 3, { 2, 1, 0 } }; // accepted
} c;
struct E
{
A a4;
E ():
a4 {3, { 2, 1, 0 } } { } // accepted
} e;
$ g++ x.cc
x.cc:6:7: error: initializer for flexible array member 'int B::a1 []'
6 | int a1[] = { 2, 1, 0 }; // rejected (see pr72775)
| ^~
x.cc:11:27: error: non-static initialization of a flexible array member
11 | A a2 = { 3, { 2, 1, 0 } }; // accepted
| ^
x.cc: In constructor 'E::E()':
x.cc:19:24: error: non-static initialization of a flexible array member
19 | a4 {3, { 2, 1, 0 } } { } // accepted
| ^
C and E are diagnosed as non-static initialization which is fine.
But D is still accepted:
$ cat t.cc
struct A { int n, a[]; };
struct D
{
int n, a3[];
D ():
n (3),
a3 {2, 1, 0} { } // silently accepted
} d;
D* foo ()
{
return new D;
}
void bar ()
{
volatile D vd;
}
$ g++ -S -O3 t.cc
$ cat t.s
.file "t.cc"
.text
.p2align 4
.globl _Z3foov
.type _Z3foov, @function
_Z3foov:
.LFB3:
.cfi_startproc
subq $8, %rsp
.cfi_def_cfa_offset 16
movl $4, %edi <<<--- allocate only 4 byte, 16 neeeded
call _Znwm
movdqa .LC0(%rip), %xmm0
movups %xmm0, (%rax)
addq $8, %rsp
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE3:
.size _Z3foov, .-_Z3foov
.p2align 4
.globl _Z3barv
.type _Z3barv, @function
_Z3barv:
.LFB4:
.cfi_startproc <<<--- didn't I declare vd as volatile?
ret
.cfi_endproc
.LFE4:
.size _Z3barv, .-_Z3barv
.section .text.startup,"ax",@progbits
.p2align 4
.type _GLOBAL__sub_I_d, @function
_GLOBAL__sub_I_d:
.LFB6:
.cfi_startproc
movdqa .LC0(%rip), %xmm0
movaps %xmm0, d(%rip)
ret
.cfi_endproc
.LFE6:
.size _GLOBAL__sub_I_d, .-_GLOBAL__sub_I_d
.section .init_array,"aw"
.align 8
.quad _GLOBAL__sub_I_d
.globl d
.bss
.align 16
.type d, @object
.size d, 4
d:
.zero 4 <<<--- object has only 4 bytes, 16 needed
.section .rodata.cst16,"aM",@progbits,16
.align 16
.LC0:
.long 3
.long 2
.long 1
.long 0
.ident "GCC: (GNU) 9.0.0 20190104 (experimental)"
.section .note.GNU-stack,"",@progbits
