Re: -freg-struct-return?

From: Jakub Jelinek
Date: Thu Feb 22 2007 - 04:53:47 EST

On Thu, Feb 22, 2007 at 12:09:04AM -0800, Jeremy Fitzhardinge wrote:
> Arjan van de Ven wrote:
> > Do we know how many gcc bugs this has? (regparm used to have many)
> > other than that.. sounds like a win...
> >
> The documentation suggests that its the preferred mode of operation, and
> that its the default on platforms where gcc is the primary compiler. So
> the fact that it isn't for Linux suggests either an oversight or that it
> is actually broken...

It is used for Linux on many architectures (x86_64, sparc64, ia64,
ppc{,64}, arm, sh, m68k to name just a few), but it is an ABI decision,
so e.g. on i386 is not used by default as the ABI mandates structs/unions
are returned in memory.

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