[PATCH][ARM] PR target/70008

[Kyrill Tkachov]

Hi Michael,

On 29/02/16 04:47, Michael Collison wrote:
> This patches address PR 70008, where a reverse subtract with carry instruction can be generated in thumb2 mode. It was tested with no regressions in arm and thumb modes on the following targets:
>
> arm-none-linux-gnueabi
> arm-none-linux-gnuabihf
> armeb-none-linux-gnuabihf
> arm-none-eabi
>
> Okay for trunk?
>
> 2016-02-28  Michael Collison  <michael.collison@linaro.org>
>
>     PR target/70008
>     * config/arm/arm.md (*subsi3_carryin): Only match pattern if
>     TARGET_ARM due to 'rsc' instruction alternative.
>     * config/arm/thumb2.md (*thumb2_subsi3_carryin): New pattern.
>
>

The *subsi3_carrying pattern has the arch attribute:
    (set_attr "arch" "*,a")

That means that the second alternative that generates the RSC instruction is only enabled
for ARM mode. Do you have a testcase where this doesn't happen and this pattern generates
the second alternative for Thumb2?

Thanks,
Kyrill