GCC error std :: sin?

Question

The following code (with -O3 -ffast-math):

#include <cmath>

float a[4];

void sin1() {
    for(unsigned i = 0; i < 4; i++) a[i] = sinf(a[i]);
}

Compiles a vectorized version of sinf (_ZGVbN4v_sinf):

sin1():
        sub     rsp, 8
        movaps  xmm0, XMMWORD PTR a[rip]
        call    _ZGVbN4v_sinf
        movaps  XMMWORD PTR a[rip], xmm0
        add     rsp, 8
        ret

But when I use the C ++ version of sinf (std :: sin), vectorization does not occur:

void sin2() {
    for(unsigned i = 0; i < 4; i++) a[i] = std::sin(a[i]);
}

sin2():
        sub     rsp, 8
        movss   xmm0, DWORD PTR a[rip]
        call    sinf
        movss   DWORD PTR a[rip], xmm0
        movss   xmm0, DWORD PTR a[rip+4]
        call    sinf
        movss   DWORD PTR a[rip+4], xmm0
        movss   xmm0, DWORD PTR a[rip+8]
        call    sinf
        movss   DWORD PTR a[rip+8], xmm0
        movss   xmm0, DWORD PTR a[rip+12]
        call    sinf
        movss   DWORD PTR a[rip+12], xmm0
        add     rsp, 8
        ret

Compiler explorer code