On Mon, 22 Feb 2021, Uros Bizjak wrote:
> The intention of HONOR_REG_ALLOC_ORDER is to ensure that IRA allocates
> registers in the order given by REG_ALLOC_ORDER. However in
> ira_better_spill_reload_regno_p, there is still a place where the
> calculation depends on the presence of REG_ALLOC_ORDER, ignoring
> HONOR_REG_ALLOC_ORDER macro altogether. The patch uses the correct macro
> at this place.
>
> On the other hand, assign_hard_reg function respects HONOR_REG_ALLOC_ORDER,
> but expects this macro to return 1 to avoid internal cost calculations.
> As the macro is defined to 0 by default, it is expected that targets redefine
> HONOR_REG_ALLOC_ORDER to return nonzero value, even if REG_ALLOC_ORDER
> is defined. This approach is prone to errors, so the patch defines
> HONOR_REG_ALLOC_ORDER to 1 by default if REG_ALLOC_ORDER is defined.
>
> 2021-02-22 Uroš Bizjak <ubiz...@gmail.com>
>
> gcc/
> * defaults.h (HONOR_REG_ALLOC_ORDER): If not defined,
> define to 1 if REG_ALLOC_ORDER is defined.
> * doc/tm.texi.in (HONOR_REG_ALLOC_ORDER):
> Describe new default definition.
> * doc/tm.texi: Regenerate.
> * ira-color.c (ira_better_spill_reload_regno_p):
> Use HONOR_REG_ALLOC_ORDER instead of REG_ALLOC_ORDER
> to determine better spill reload regno.
>
> Patch was bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
>
> OK for gcc-12 when it opens?
OK in case Vlad doesn't have a better suggestion or further comments.
Do you have an idea for how many targets the changed default is an
actual change?
Thanks,
Richard.
> Uros.
>
--
Richard Biener <rguent...@suse.de>
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