[PATCH][AArch64] Restore recog state after finding pre-madd instruction

[Marcus Shawcroft]

On 29 October 2014 10:03, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
> Hi all,
>
> This patch fixes an issue with the final_prescan workaround for the
> Cortex-A53 erratum 835769
> where calling recog_memoized could modify the recog data for the
> multiply-accumulate instruction
> when looking at a preceding asm block. This can lead to wrong code
> generation.
>
> The solution is to call extract_constrain_insn_cached to restore the recog
> data before exiting
> aarch64_madd_needs_nop.
>
> Bootstrapped and tested on aarch64-none-linux-gnu.
> A compile testcase is added demonstrating the issue.
>
> Ok for trunk?

Ok /Marcus