GCC Status Report (2004-03-09)

[Jakub Jelinek]

On Thu, Mar 18, 2004 at 08:26:30PM -0500, Richard Kenner wrote:
> I don't know what to think about /u overall.  It's becoming more and more
> clear that it's the source of a lot of trouble and probably is becoming
> less and less useful with aliasing code around anyway.  I'd be in favor
> of trying the experiment of only using it on data that's *never* explicitly
> stored (like constant-pool or items with static initializers).  So we
> disallow stores to /u.

That would be certainly safest and the UNCHANGING would really mean
unchanging.  But I hope we could at least extend it to objects which are
*never* stored into in current function (see if the object is initialized
in the function currently expanded into RTL, if not, use RTX_UNCHANGING_P
for it as well, otherwise perhaps use some other bit or alias set).

	Jakub