Re: [PATCH][ARM/AArch64] Properly cost rev16 operand

[Kyrill Tkachov <kyrylo dot tkachov at arm dot com>]

Ping.
https://gcc.gnu.org/ml/gcc-patches/2015-05/msg00013.html

Thanks,
Kyrill
On 01/05/15 09:24, Kyrill Tkachov wrote:
> Hi all,
>
> It occurs to me that in the IOR-of-shifts form of the rev16 operation we should be costing the operand properly.
> For that we'd want to reuse the aarch_rev16_p function that does all the heavy lifting and get it to write the
> innermost operand of the rev16 for further costing. In the process we relax that function a bit to accept any
> rtx as the operand, not just REGs so that we can calculate the cost of moving them in a register appropriately.
>
> This patch does just that and updates the arm and aarch64 callsites appropriately so that the operands are
> processed properly.
>
> In practice I don't expect this to make much difference since this patterns occurs rarely anyway, but it seems
> like the 'right thing to do' (TM).
>
> Bootstrapped and tested on arm,aarch64.
>
> Ok for trunk?
>
> Thanks,
> Kyrill
>
> 2015-05-01  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>
>       * config/arm/aarch-common-protos.h (aarch_rev16_p): Update signature
>       to take a second argument.
>       * config/arm/aarch-common.c (aarch_rev16_p): Add second argument.
>       Write inner-most rev16 argument to it if recognised.
>       (aarch_rev16_p_1): Likewise.
>       * config/arm/arm.c (arm_new_rtx_costs): Properly cost rev16 operand
>       in the IOR case.
>       * config/aarch64/aarch64.c (aarch64_rtx_costs): Likewise.