[Bug tree-optimization/55614] [4.6/4.7 Regression] vector extensions cause movdqa to be generated for memcpy on unaligned buffer

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55614



--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-07 
15:28:30 UTC ---

(In reply to comment #5)

> How can a union have alignment 8 if it contains a field with alignment 128? 

> That should only happen if the field is a bit-field...



That is what the memcpy folding folds it to.  We could perhaps stop for 4.6/4.7

doing such replacements in memcpy folding if it would try to decrease alignment

of some aggregate, but then we risk regressing generated code quality.