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Re: ipa on all files together
On Tue, Nov 2, 2010 at 1:40 AM, Hongtao <yu171@purdue.edu> wrote:
> ?On 11/01/10 20:35, Diego Novillo wrote:
>> 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.
> ?Thanks. But can I only keep the third pass, i.e. ?I want to perform a
> pass only on all units together without on each unit separately?
If -flto-slim support gets merged then yes.
Richard.