[Bug rtl-optimization/45678] [4.4/4.5/4.6 Regression] crash on vector code with -m32 -msse

[hjl dot tools at gmail dot com]

------- Comment #19 from hjl dot tools at gmail dot com  2010-09-16 14:17 -------
(In reply to comment #17)
> That's true.  But many expanders can make use of DECL_ALIGN information, e.g.
> to choose faster code.  If cfgexpand keeps doing what it does now, namely
> bumping DECL_ALIGN of variables up to PREFERRED_STACK_BOUNDARY even when in the
> end the stack block doesn't end up being aligned that way, then it lies to the
> expander

The problem isn't limited to stack.

> and that will hit us again and again.  On x86-64/i686, I don't think we want to
> prevent memcpy folding as your patch does, at least not for CPUs where movu* is
> fast.

That is true. Whatever we do, we can't lie about
alignment, on stack or not. Once we fix that,
the rest shouldn't be too hard to fix.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45678