Re: [PATCH] Fix another problem with RTX_UNCHANGING_P (take 2)

[Richard Henderson <rth at redhat dot com>]

On Mon, Dec 15, 2003 at 04:50:10AM -0500, Jakub Jelinek wrote:
> Another alternative is to fix IA-32 backend (and likely others too).
> There are many places where i386.md has chunks like:
>    (set (mem:BLK (match_dup 3))
>         (const_int 0))
> The code would need changing, so that at least the RTX_UNCHANGING_P flag
> is propagated from ix86_expand_* memory argument(s) to the patterns.
> This matters for clrstr, movstr, cmpstr etc.

This is certainly most correct.  We're currently losing all sorts
of stuff relevant to the aliasing code.

> 	* expr.c (store_constructor): Don't set RTX_UNCHANGING_P for
> 	clear_storage's argument.

This is certainly most appropriate for 3.3.  For 3.4 it'd be nice
to fix the i386 backend and possibly revert your previous patch.


r~