> __attribute__((noipa)) void
> bar (void)
> {
> __builtin_exit (0);
> }
>
> __attribute__((noipa)) void
> foo (void)
> {
> for (int i = 0; i < 1000; ++i)
> for (int j = 0; j < 1000; ++j)
> for (int k = 0; k < 1000; ++k)
> for (int l = 0; l < 1000; ++l)
> for (int m = 0; m < 1000; ++m)
> for (int n = 0; n < 1000; ++n)
> for (int o = 0; o < 1000; ++o)
> for (int p = 0; p < 1000; ++p)
> for (int q = 0; q < 1000; ++q)
> for (int r = 0; r < 1000; ++r)
> for (int s = 0; s < 1000; ++s)
> for (int t = 0; t < 1000; ++t)
> for (int u = 0; u < 1000; ++u)
> for (int v = 0; v < 1000; ++v)
> for (int w = 0; w < 1000; ++w)
> for (int x = 0; x < 1000; ++x)
> for (int y = 0; y < 1000; ++y)
> for (int z = 0; z < 1000; ++z)
> for (int a = 0; a < 1000; ++a)
> for (int b = 0; b < 1000; ++b)
> bar ();
> }
>
> int
> main ()
> {
> foo ();
> }
> reaches the maximum count already on the 11th loop.
This should not happen - this is a reason why we esimate in sreals and
convert to profile_counts only later. In this case we should push down
the profile_count of entry block (to 0)
freq_max = 0;
FOR_EACH_BB_FN (bb, cfun)
if (freq_max < BLOCK_INFO (bb)->frequency)
freq_max = BLOCK_INFO (bb)->frequency;
/* Scaling frequencies up to maximal profile count may result in
frequent overflows especially when inlining loops.
Small scalling results in unnecesary precision loss. Stay in
the half of the (exponential) range. */
freq_max = (sreal (1) << (profile_count::n_bits / 2)) / freq_max;
if (freq_max < 16)
freq_max = 16;
I am looking on what goes wrong here.
Honza
