Question about -mpreferred-stack-boundary

[Richard Henderson]

On Sat, Feb 03, 2001 at 02:56:06PM +0100, Andreas Jaeger wrote:
> I should have descripted the problem in more detail: glibc's startup
> code aligns the stack to 32 bytes - and then calls a function.  Now,
> if you tell me that the stack has to be aligned (e.g. to 32 bytes)
> *after* the push of the return address, then glibc is wrong - but if
> it has to be aligned *before* the push of the return address, we might
> have a bug in GCC.

The stack should be aligned *before* the push of the return address.
That is, the first argument should be appropriately aligned.

The ABI Intel is promoting for __m128 pads the argument list such
that a __m128 argument is always aligned.  So there is 4 bytes of
padding in foo(int, int, int, __m128).


r~