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Re: PATCH: PR target/40838: gcc shouldn't assume that the stack is aligned
Hi,
On Mon, 19 Oct 2009, H.J. Lu wrote:
> The issues are
>
> 1. The incoming stack alignment can't be changed after RTL expansion
> starts.
And that's the thing. Just move the prologue expansion to after the body
expansion (see cfgexpand.c) and you should be set. No doubt you'll hit
some ugly obstacles, but that should be the way forward.
> 2. When -mstackrealign is used, we want to use 4 byte incoming stack
> alignment on functions which use SSE vector insns.
> 3. SSE vector insns may be generated by intrinsics, vectorizer and
> vector operations.
All of these will be automatically taken care off when (1) is solved. I
really think it would be worth it. Fiddling with stack alignment in the
vectorizer (though that's the first alignment requirers you'll hit) is not
going to fly in the long run.
Ciao,
Michael.