[patch] set -mabi=altivec with -ftree-vectorize

[Daniel Jacobowitz]

On Tue, Aug 07, 2007 at 11:58:11AM -0400, Andrew Pinski wrote:
> The ABI is only difference if you actually use altivec registers or
> VMX sized vectors (except for vector long long which does not
> exist).

That's almost right, but not quite.  The required stack alignment
difference is an ABI issue.

> So I think the warning is wrong and will get people confused even
> more.   In most cases you only want to compile some parts of the
> program with -maltivec -mabi=altivec and then only call those parts
> when VMX exists.  This is very very common in generic programs that
> people compile for PowerPC and allow to run on mutliple pieces of
> hardware.  Remember not all users of GCC can provide full different
> versions of their program in an effient manor.

Then they should either use just -maltivec without -mabi=altivec, or
someone should implement support for "don't care" tagging.  As things
stand now code can go horribly wrong if the stack does not happen to
be sufficiently aligned.

I wouldn't object to a linker option to suppress the warnings; that's
been suggested before and we may need it on ARM for the -fshort-wchar
tests.

-- 
Daniel Jacobowitz
CodeSourcery