https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99633
Bug ID: 99633
Summary: s1113 benchmark of TSVC is unrolled by icc and not by
gcc and runs faster on znver3
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: hubicka at gcc dot gnu.org
Target Milestone: ---
typedef float real_t;
#define iterations 100000
#define LEN_1D 32000
#define LEN_2D 256
// array definitions
real_t a[LEN_1D],b[LEN_1D],c[LEN_1D],d[LEN_1D],e[LEN_1D];
int main(struct args_t * func_args)
{
// linear dependence testing
// one iteration dependency on a(LEN_1D/2) but still vectorizable
//initialise_arrays(__func__);
//gettimeofday(&func_args->t1, NULL);
for (int nl = 0; nl < 2*iterations; nl++) {
for (int i = 0; i < LEN_1D; i++) {
a[i] = a[LEN_1D/2] + b[i];
}
//dummy(a, b, c, d, e, aa, bb, cc, 0.);
}
return a[10];
}
Is unrolled twice by icc and runs 1.5s instead of 2.6s when built with gcc.
-funroll-loops fixes the issue, but it suggests we may want to unroll by
default on zver3
