[Bug tree-optimization/58806] New attribute for functions that access memory only through their arguments

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58806

--- Comment #4 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Marc Glisse from comment #3)
> I should look at where exactly the difference between memcpy and init plays a 
> role.

It is in call_may_clobber_ref_p_1 that memcpy takes a shortcut: it only checks
for refs_may_alias_p_1 with its first argument, instead of going through the
usual intersection of clobber sets.