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Re: Disable sibcall optimization when -Os
- From: <tm_gccmail at mail dot kloo dot net>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: Geoff Keating <geoffk at geoffk dot org>, gcc-patches at gcc dot gnu dot org
- Date: Mon, 14 Apr 2003 13:19:28 -0700 (PDT)
- Subject: Re: Disable sibcall optimization when -Os
On Sat, 12 Apr 2003, Jan Hubicka wrote:
> > tm_gccmail at mail dot kloo dot net writes:
> >
> > > On my testcases for the SH4, I see significant code expansion (~8%) when
> > > sibcall optimization is enabled due to:
> > >
> > > 1) A bunch of register pushes (typically 8) generated (16 bytes or so)
> > >
> > > 2) A BARRIER generated afterwards which forces 32-byte alignment
> > > (average 16 bytes)
>
> The alignment should not happen for -Os or is it required for
> correctness?
>
> Honza
No, it's not required for correctness, but the extra register pushes still
occur.
Toshi