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

[ebotcazou at gcc dot gnu.org]

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



--- Comment #7 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2012-12-07 
15:40:08 UTC ---

> 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.



It's the build_aligned_type paths in fold_builtin_memory_op, right?  No wonder

you get problems by breaking such a fundamental invariant as the type

alignment.



I guess you can kludge in SRA and disable the COMPONENT_REF thing if the

platform isn't STRICT_ALIGNMENT.