Use of option -fprofile-arcs is not compatible with -fprofile-use

[Edmar Wienskoski-RA8797]

I said if you compile val-prof-1.c the same way bprob-1.c is compiled 
you get an warning.

gcc -g -fprofile-arcs val-prof-1.c -o val-prof-1.x1



Lijuan Hai wrote:
> seen in gcc-4.2, gcc.misc-tests/bprob-1.c is compiled with
> -fprofile-arcs and -fbranch-probabilities.
> gcc.dg/tree-prof/val-prof-1.c is compiled with -fprofile-generate and
> -fprofile-use. so there won't be any warnings.
>
> 2008/4/25 Edmar Wienskoski-RA8797 <edmar@freescale.com>:
>   
>> The test case gcc.misc/bprob-1.c is compiled with fprofile-arcs /
>> fprofile-use.
>>
>>  The option fprofile-arcs does not enable value profiling.
>>
>>  At the second stage compilation, the option fprofile-use enables value
>> profiling. Within tree_find_values_to_profile, if one of the value
>> optimizations algorithms sees an optimization opportunity, it will push an
>> histogram on stack. Later, compute_value_histograms will call
>> get_coverage_counts to load this histogram, but none where generated.
>>
>>  A warning is issued which means a FAIL under dejagnu.
>>
>>  I found this problem with bprob-1.c while debugging a new value profile
>> optimization. But it can be reproduced in any target, with non-modified gcc,
>> at any optimization level, using one of the value profile test cases and
>> compiler options fprofile-arcs / fprofile-use (same used with bprob-1.c).
>>
>>  Here is an example using gcc.dg/tree-prof/val-prof-1.c:
>>  ./gcc-trunk-reference/install_e600/bin/gcc -g -fprofile-arcs val-prof-1.c
>> -o val-prof-1.x1
>>  ./val-prof-1.x1
>>  ./gcc-trunk-reference/install_e600/bin/gcc -g -fprofile-use val-prof-1.c -o
>> val-prof-1.x2
>>  val-prof-1.c: In function 'main':
>>  val-prof-1.c:17: warning: no coverage for function 'main' found
>>
>>  IMHO there are 3 ways to go with this:
>>  1 - Require user behavior change (create new option -fprofile-arcs-use to
>> match -fprofile-arcs, mismatch of options is bad user behavior)
>>  2 - Record on the .gcda file how the first stage were done (fprofile-arcs /
>> fprofile-generate, etc) and use it to disable other optimizations under
>> fprofile-use (Does this already exists ?, I am not familiar with the .gcda
>> layout)
>>  3 - Let get_coverage_counts ignore inconsistencies when loading data.
>>
>>  Helps / comments are appreciated.
>>
>>  Edmar
>>
>>
>>
>>
>>     
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