[Bug gcov-profile/55674] [4.8 Regression] >20% size increase of lto/pgo binaries since r193747

[tejohnson at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55674

--- Comment #8 from Teresa Johnson <tejohnson at google dot com> 2012-12-13 18:23:08 UTC ---
Dumb mistake in my previous fix to the lto support. Here is the patch
that fixes it, I will submit for review after regression testing
completes:


Index: lto-cgraph.c
===================================================================
--- lto-cgraph.c (revision 194404)
+++ lto-cgraph.c (working copy)
@@ -1368,7 +1368,9 @@
          so we need to account for a non-zero histogram entry at new_ix.  */
       unsigned new_ix = gcov_histo_index (scaled_min);
       lto_gcov_summary.histogram[new_ix].min_value
-          = MIN (lto_gcov_summary.histogram[new_ix].min_value, scaled_min);
+          = (lto_gcov_summary.histogram[new_ix].num_counters
+             ? MIN (lto_gcov_summary.histogram[new_ix].min_value, scaled_min)
+             : scaled_min);
       /* Some of the scaled counter values would ostensibly need to be placed
          into different (larger) histogram buckets, but we keep things simple
          here and place the scaled cumulative counter value in the bucket

Please let me know how this affects the mozilla size.

Thanks,
Teresa

On Thu, Dec 13, 2012 at 7:49 AM, Teresa Johnson <tejohnson@google.com> wrote:
> Reproduced. Looks like somehow my fix to stream this through LTO is
> not working properly. I see that the min count is valid when
> generating the .o file, but goes to zero when we do the link(lto)
> phase. Hopefully this means that the heuristic itself is not broken.
> =)  I'll see if I can root cause this and have a fix today.
>
> Teresa
>
> On Thu, Dec 13, 2012 at 7:06 AM, markus at trippelsdorf dot de
> <gcc-bugzilla@gcc.gnu.org> wrote:
>>
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55674
>>
>> --- Comment #6 from Markus Trippelsdorf <markus at trippelsdorf dot de> 2012-12-13 15:06:12 UTC ---
>> (In reply to comment #5)
>>> Ok, I will download tramp3d-v4 right now and see what is going on. Can
>>> you send me the full set of options you are using to compile it?
>>>
>>
>> g++ -w -O3 -fprofile-generate -march=native tramp3d-v4.cpp
>> ./a.out --cartvis 1.0 0.0 --rhomin 1e-8 -n 20
>> g++ -w -O3 -fprofile-use -flto=4 -march=native tramp3d-v4.cpp
>>
>> --
>> Configure bugmail: http://gcc.gnu.org/bugzilla/userprefs.cgi?tab=email
>> ------- You are receiving this mail because: -------
>> You are on the CC list for the bug.
>
>
>
> --
> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413