Hi,
this patch makes maybe_hot_frequency_p to use multiplication instead of
division.
This eliminates roundoff errors that are quite serious in this case:
HOT_BB_FREQUENCY_FRACTION is 1000 while frequencies are scaled from 0...10000.
If there is loop in function then most likely no BB is considered cold.
Hopefully
I will get rid of those fixed point arithmetic issues, but lets first fix the
bugs.
Bootstrapped/regtested x86_64-linux, will commit it shortly.
Honza
* predict.c (maybe_hot_frequency_p): Avoid division.
Index: predict.c
===================================================================
--- predict.c (revision 236850)
+++ predict.c (working copy)
@@ -115,8 +115,8 @@ maybe_hot_frequency_p (struct function *
return false;
if (PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION) == 0)
return false;
- if (freq < (ENTRY_BLOCK_PTR_FOR_FN (fun)->frequency
- / PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION)))
+ if (freq * PARAM_VALUE (HOT_BB_FREQUENCY_FRACTION)
+ < ENTRY_BLOCK_PTR_FOR_FN (fun)->frequency)
return false;
return true;
}
