[Bug tree-optimization/49442] [4.5/4.6/4.7 Regression] Misaligned store support pessimization

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49442

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-06-17 08:15:38 UTC ---
ICC apparently has __assume_aligned (ptr, align) for this, and also
#pragma vector {aligned,unaligned,always,nontemporal}.
For alignment, I'd say having both hard alignment and likely alignment hints
somewhere in the code would be better than ptr_align attribute on the
arguments,
so something like
__builtin_assume_aligned (ptr, align[, misalign])
and
__builtin_likely_aligned (ptr, align[, misalign]);
would be helpful.  The question is if they shouldn't return the pointer again,
and let the user write it in the form
ptr = __builtin_assume_aligned (ptr, 16);
which would be optimized away when we compute the alignment.