ipa on all files together

[Diego Novillo]

On Mon, Nov 1, 2010 at 19:57, Hongtao <yu171@purdue.edu> wrote:
>  Hi All,
>
> While using gcc-4.6 with option -flto, I found that interprocedural
> analysis were performed on each source file separately. For example for
> the pass pass_ipa_pta, if we compile two files like :
>         gcc -O -flto f1.c f2.c
> we have the pass run twice, one for each source file. So is there a way
> that can perform IPA on all source files together?

With -combine you used to be able to do this, but it has been removed
in favour of -flto (actually, I'm not quite sure whether it's been
removed already, but it's on the chopping block).

With -flto, IPA will be performed on all the files together, as well
as each file separately.  In your example, IPA runs 3 times.  Once for
each f1.c and f2.c, and a third time with both f1.o and f2.o as a
single translation unit.


Diego.