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Re: [TESTCASE] Minimized testcase for AltiVec segfault


> Date: Fri, 1 Mar 2002 09:26:02 +1100
> Cc: kumar.gala@motorola.com, degger@fhm.edu, gcc@gcc.gnu.org,
>    dje@watson.ibm.com
> From: Aldy Hernandez <aldyh@redhat.com>
> 
> > Why can't varargs and vector arguments be supported under the SVR4
> > ABI?
> 
> because things won't be aligned properly.  and if they were,
> we'd no longer be SVR4 abi compliant.

Can you explain what doesn't get aligned?  SVR4 always had 16-byte
stack alignment (unlike some other ppc ABIs).

> > Isn't altivec still useful even if you can't pass vectors as
> > arguments?
> 
> sure, but we don't need a flag to do that.

But we do!  We need a flag to tell the compiler _not_ to use altivec
instructions for block copies, for example, on non-altivec chips.

-- 
- Geoffrey Keating <geoffk@geoffk.org> <geoffk@redhat.com>


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