[Bug target/39137] [4.4 Regression] -mpreferred-stack-boundary=2 causes lots of dynamic realign

hjl dot tools at gmail dot com gcc-bugzilla@gcc.gnu.org
Tue Feb 10 21:02:00 GMT 2009



------- Comment #7 from hjl dot tools at gmail dot com  2009-02-10 21:02 -------
(In reply to comment #6)
> This would mean -Os vs. -O2 gives different __alignof__(long long) values, I
> think that's a bad idea.  I think a new option to disable dynamic realignment
> or at least do that if estimated stack size is <= 64 bits would be better.
> 

We do stack alignment to satisfy variable alignment requirement. You
don't want to disable it blindly. The proper way to avoid stack
alignment is to tell compiler not to align variable on stack.
We can add a new option, -malign-double=4, to align DI/DF to
4 bytes on stack.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39137



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