[Bug tree-optimization/99394] s254 benchmark of TSVC is vectorized by clang and not by gcc

[hubicka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99394

--- Comment #3 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
testcase is:

typedef float real_t;

#define iterations 100000
#define LEN_1D 32000
#define LEN_2D 256
// array definitions
real_t flat_2d_array[LEN_2D*LEN_2D];

real_t x[LEN_1D];

real_t a[LEN_1D],b[LEN_1D],c[LEN_1D],d[LEN_1D],e[LEN_1D],
bb[LEN_2D][LEN_2D],cc[LEN_2D][LEN_2D],tt[LEN_2D][LEN_2D];

int indx[LEN_1D];

real_t* __restrict__ xx;
real_t* yy;

// %2.5

real_t s254(void)
{

//    scalar and array expansion
//    carry around variable

    real_t x;
    for (int nl = 0; nl < 4*iterations; nl++) {
        x = b[LEN_1D-1];
        for (int i = 0; i < LEN_1D; i++) {
            a[i] = (b[i] + x) * (real_t).5;
            x = b[i];
        }
    }

}