Re: do -fprofile-arcs and -fbranch-probabilities help to set bb->count?

[Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>]

Liu Haibin wrote:
> Hi,
>
> I wanted to use bb->count, so I expected that -fprofile-arcs and
> -fbranch-probabilities would help. I added printf just before
> peephole2 optimization and ran the following.
>
> $gcc -O3 -fprofile-arcs test.c -o test
> $./test (which produced test.gcno only, but no test.gcda)
> $gcc -O3 -fprofile-arcs -fbranch-probabilities test.c -o test

Easier to use -fprofile-generate and -fprofile-use:

gcc -O3 -fprofile-generate test.c -o test (produces test.gcno)
./test (now should have as well test.gcda)
gcc -O3 -fprofile-use test.c -o test

Paolo