Re: Backport: [Patch AArch64] Reinstate CANNOT_CHANGE_MODE_CLASS to fix pr67609

[Marcus Shawcroft <marcus.shawcroft@gmail.com>]

On 18 December 2015 at 12:13, James Greenhalgh <james.greenhalgh@arm.com> wrote:

> Looking back at the patch just before I hit commit, the 4.9 backport was
> a little different (as we still have a CANNOT_CHANGE_MODE_CLASS there).
> We can drop the aarch64-protos.h and aarch64.h changes, and we need to
> change the sense of the new check, such that we can return true for the
> case added by this patch, and false for the limited number of other safe
> cases in 4.9.
>
> Bootstrapped on aarch64-none-linux-gnu.
>
> OK?
>
> Thanks,
> James
>
> ---
> gcc/
>
> 2015-12-14  James Greenhalgh  <james.greenhalgh@arm.com>
>
>         Backport from mainline.
>         2015-12-09  James Greenhalgh  <james.greenhalgh@arm.com>
>
>         PR rtl-optimization/67609
>         * config/aarch64/aarch64.c
>         (aarch64_cannot_change_mode_class): Don't permit word_mode
>         subregs of full vector modes.
>         * config/aarch64/aarch64.md (aarch64_movdi_<mode>low): Use
>         zero_extract rather than truncate.
>         (aarch64_movdi_<mode>high): Likewise.
>
> gcc/testsuite/
>
> 2015-12-14  James Greenhalgh  <james.greenhalgh@arm.com>
>
>         Backport from mainline.
>         2015-12-09  James Greenhalgh  <james.greenhalgh@arm.com>
>
>         PR rtl-optimization/67609
>         * gcc.dg/torture/pr67609.c: New.
>

OK /Marcus