[PATCH][ARM] PR 68143 Properly update memory offsets when expanding setmem

Kyrill Tkachov kyrylo.tkachov@arm.com
Mon Nov 9 09:27:00 GMT 2015


On 06/11/15 10:46, Kyrill Tkachov wrote:
> Hi all,
>
> In this wrong-code PR the vector setmem expansion and arm_block_set_aligned_vect in particular
> use the wrong offset when calling adjust_automodify_address. In the attached testcase during the
> initial zeroing out we get two V16QI stores, but they both are recorded by adjust_automodify_address
> as modifying x+0 rather than x+0 and x+12 (the total size to be written is 28).
>
> This led to the scheduling pass moving the store from "x.g = 2;" to before the zeroing stores.
>
> This patch fixes the problem by keeping track of the offset to which stores are emitted and
> passing it to adjust_automodify_address as appropriate.
>
> From inspection I see arm_block_set_unaligned_vect also has this issue so I performed the same
> fix in that function as well.
>
> Bootstrapped and tested on arm-none-linux-gnueabihf.
>
> Ok for trunk?
>
> This bug appears on GCC 5 too and I'm currently testing this patch there.
> Ok to backport to GCC 5 as well?

Bootstrap and testing for arm-none-linux-gnueabihf on GCC 5 branch looks ok too.

Kyrill

>
> Thanks,
> Kyrill
>
> 2015-11-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>
>     PR target/68143
>     * config/arm/arm.c (arm_block_set_unaligned_vect): Keep track of
>     offset from dstbase and use it appropriately in
>     adjust_automodify_address.
>     (arm_block_set_aligned_vect): Likewise.
>
> 2015-11-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>
>     PR target/68143
>     * gcc.target/arm/pr68143_1.c: New test.



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