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Cap frequency of recursive calls by 90%

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* predict.c (estimate_bb_frequencies): Cap recursive calls by 90%.
This commit is contained in:
Jan Hubicka 2020-08-01 17:02:24 +02:00
parent 7d599ad27b
commit 13cdbb6a97
1 changed files with 24 additions and 1 deletions
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25
gcc/predict.c
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@ -3892,7 +3892,30 @@ estimate_bb_frequencies (bool force)
cfun->cfg->count_max = profile_count::uninitialized ();
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
{
sreal tmp = BLOCK_INFO (bb)->frequency * freq_max + sreal (1, -1);
sreal tmp = BLOCK_INFO (bb)->frequency;
if (tmp >= 1)
{
gimple_stmt_iterator gsi;
tree decl;
/* Self recursive calls can not have frequency greater than 1
or program will never terminate. This will result in an
inconsistent bb profile but it is better than greatly confusing
IPA cost metrics. */
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
if (is_gimple_call (gsi_stmt (gsi))
&& (decl = gimple_call_fndecl (gsi_stmt (gsi))) != NULL
&& recursive_call_p (current_function_decl, decl))
{
if (dump_file)
fprintf (dump_file, "Dropping frequency of recursive call"
" in bb %i from %f\n", bb->index,
tmp.to_double ());
tmp = (sreal)9 / (sreal)10;
break;
}
}
tmp = tmp * freq_max + sreal (1, -1);
profile_count count = profile_count::from_gcov_type (tmp.to_int ());
/* If we have profile feedback in which this function was never