Re: [PATCH 1/2] gcov: test switch/break line counts

["Jørgen Kvalsvik" <jorgen.kvalsvik@woven-planet.global>]

On 13/10/2022 13:39, Richard Biener wrote:
> On Tue, Oct 11, 2022 at 2:43 PM Jørgen Kvalsvik
> <jorgen.kvalsvik@woven-planet.global> wrote:
>>
>> The coverage support will under some conditions decide to split edges to
>> accurately report coverage. By running the test suite with/without this
>> edge splitting a small diff shows up, addressed by this patch, which
>> should catch future regressions.
>>
>> Removing the edge splitting:
>>
>>     $ diff --git a/gcc/profile.cc b/gcc/profile.cc
>>     --- a/gcc/profile.cc
>>     +++ b/gcc/profile.cc
>>     @@ -1244,19 +1244,7 @@ branch_prob (bool thunk)
>>                     Don't do that when the locuses match, so
>>                     if (blah) goto something;
>>                     is not computed twice.  */
>>     -             if (last
>>     -                 && gimple_has_location (last)
>>     -                 && !RESERVED_LOCATION_P (e->goto_locus)
>>     -                 && !single_succ_p (bb)
>>     -                 && (LOCATION_FILE (e->goto_locus)
>>     -                     != LOCATION_FILE (gimple_location (last))
>>     -                     || (LOCATION_LINE (e->goto_locus)
>>     -                         != LOCATION_LINE (gimple_location (last)))))
>>     -               {
>>     -                 basic_block new_bb = split_edge (e);
>>     -                 edge ne = single_succ_edge (new_bb);
>>     -                 ne->goto_locus = e->goto_locus;
>>     -               }
>>     +
>>             if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
>>                     && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
>>                     need_exit_edge = 1;
>>
>> Assuming the .gcov files from make chec-gcc RUNTESTFLAGS=gcov.exp are
>> kept:
>>
>>     $ diff -r no-split-edge with-split-edge | grep -C 2 -E "^[<>]\s\s"
>>     diff -r sans-split-edge/gcc/gcov-4.c.gcov with-split-edge/gcc/gcov-4.c.gcov
>>     228c228
>>     <         -:  224:        break;
>>     ---
>>     >         1:  224:        break;
>>     231c231
>>     <         -:  227:        break;
>>     ---
>>     >     #####:  227:        break;
>>     237c237
>>     <         -:  233:        break;
>>     ---
>>     >         2:  233:        break;
>>
>> gcc/testsuite/ChangeLog:
> 
> OK.
> 
> Thanks,
> Richard.
> 
>>
>>         * g++.dg/gcov/gcov-1.C: Add line count check.
>>         * gcc.misc-tests/gcov-4.c: Likewise.
>> ---
>>  gcc/testsuite/g++.dg/gcov/gcov-1.C    | 8 ++++----
>>  gcc/testsuite/gcc.misc-tests/gcov-4.c | 4 ++--
>>  2 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/gcc/testsuite/g++.dg/gcov/gcov-1.C b/gcc/testsuite/g++.dg/gcov/gcov-1.C
>> index 9018b9a3a73..ee383b480a8 100644
>> --- a/gcc/testsuite/g++.dg/gcov/gcov-1.C
>> +++ b/gcc/testsuite/g++.dg/gcov/gcov-1.C
>> @@ -257,20 +257,20 @@ test_switch (int i, int j)
>>    switch (i)                           /* count(5) */
>>                                         /* branch(end) */
>>      {
>> -      case 1:
>> +      case 1:                          /* count(1) */
>>          result = do_something (2);     /* count(1) */
>> -        break;
>> +        break;                         /* count(1) */
>>        case 2:
>>          result = do_something (1024);
>>          break;
>> -      case 3:
>> +      case 3:                          /* count(3) */
>>        case 4:
>>                                         /* branch(67) */
>>          if (j == 2)                    /* count(3) */
>>                                         /* branch(end) */
>>            return do_something (4);     /* count(1) */
>>          result = do_something (8);     /* count(2) */
>> -        break;
>> +        break;                         /* count(2) */
>>        default:
>>         result = do_something (32);     /* count(1) */
>>         switch_m++;                     /* count(1) */
>> diff --git a/gcc/testsuite/gcc.misc-tests/gcov-4.c b/gcc/testsuite/gcc.misc-tests/gcov-4.c
>> index 9d8ab1c1097..498d299b66b 100644
>> --- a/gcc/testsuite/gcc.misc-tests/gcov-4.c
>> +++ b/gcc/testsuite/gcc.misc-tests/gcov-4.c
>> @@ -221,7 +221,7 @@ test_switch (int i, int j)
>>      {
>>        case 1:
>>          result = do_something (2);     /* count(1) */
>> -        break;
>> +        break;                         /* count(1) */
>>        case 2:
>>          result = do_something (1024);
>>          break;
>> @@ -230,7 +230,7 @@ test_switch (int i, int j)
>>          if (j == 2)                    /* count(3) */
>>            return do_something (4);     /* count(1) */
>>          result = do_something (8);     /* count(2) */
>> -        break;
>> +        break;                         /* count(2) */
>>        default:
>>         result = do_something (32);     /* count(1) */
>>         switch_m++;                     /* count(1) */
>> --
>> 2.34.0
>>

Thank you, I've installed the patches.

I noticed that the inclusion of diffs in the message works fine with git
generally, but could be picked up on by git format-patch && git am < patch. I
hope that does not end up causing too many problems (last time, promise!)

Thanks,
Jørgen