On Mon, Aug 20, 2018 at 06:45:37PM -0400, Michael Meissner wrote:
> In this patch earlier to improve switch behavior:
> https://gcc.gnu.org/ml/gcc-patches/2018-07/msg01957.html
>
> I noticed that the compiler wasn't generating the LWAX instruction. I tracked
> this down to the "extendsi<mode>2" insn using the "Y" constraint when it can
> optimize a load + sign extend into a single load with sign extend. The "Y"
> constraint is for DS-form offsettable addresses, and does not allow indexed
> addresses (i.e. X-form loads). This patch adds the "Z" constraint as well,
> which allows indexed addresses.
This is okay for trunk, and for backports too. Thanks!
> +/* { dg-do compile { target { powerpc*-*-* && lp64 } } } */
Maybe add a comment on why lp64 is needed here, it took me a minute :-)
Segher
