Alex Coplan <alex.cop...@arm.com> writes:
> Hello,
>
> This patch fixes PR94591. The problem was the function
> aarch64_evpc_rev_local()
> matching vector permutations that were not reversals. In particular, prior to
> this patch, this function matched the identity permutation which led to
> generating bogus REV64 insns which were rejected by the assembler.
>
> Testing:
> - New regression test which passes after applying the patch.
> - New test passes on an x64 -> aarch64-none-elf cross.
> - Bootstrap and regtest on aarch64-linux-gnu.
>
> OK to install?
>
> Thanks,
> Alex
>
> ---
>
> gcc/ChangeLog:
>
> 2020-05-19 Alex Coplan <alex.cop...@arm.com>
>
> PR target/94591
> * config/aarch64/aarch64.c (aarch64_evpc_rev_local): Don't match
> identity permutation.
>
> gcc/testsuite/ChangeLog:
>
> 2020-05-19 Alex Coplan <alex.cop...@arm.com>
>
> PR target/94591
> * gcc.c-torture/execute/pr94591.c: New test.
OK, thanks.
Richard
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index 70aa2f752b5..79c016f4dc3 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -20191,7 +20191,8 @@ aarch64_evpc_rev_local (struct expand_vec_perm_d *d)
>
> if (d->vec_flags == VEC_SVE_PRED
> || !d->one_vector_p
> - || !d->perm[0].is_constant (&diff))
> + || !d->perm[0].is_constant (&diff)
> + || !diff)
> return false;
>
> size = (diff + 1) * GET_MODE_UNIT_SIZE (d->vmode);
> diff --git a/gcc/testsuite/gcc.c-torture/execute/pr94591.c
> b/gcc/testsuite/gcc.c-torture/execute/pr94591.c
> new file mode 100644
> index 00000000000..42271ad8bce
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/execute/pr94591.c
> @@ -0,0 +1,32 @@
> +typedef unsigned __attribute__((__vector_size__(8))) V2SI_u;
> +typedef int __attribute__((__vector_size__(8))) V2SI_d;
> +
> +typedef unsigned long __attribute__((__vector_size__(16))) V2DI_u;
> +typedef long __attribute__((__vector_size__(16))) V2DI_d;
> +
> +void id_V2SI(V2SI_d *v)
> +{
> + *v = __builtin_shuffle(*v, (V2SI_d)(V2SI_u) { 0, 1 });
> +}
> +
> +void id_V2DI(V2DI_d *v)
> +{
> + *v = __builtin_shuffle(*v, (V2DI_d)(V2DI_u) { 0, 1 });
> +}
> +
> +extern void abort(void);
> +
> +int main(void)
> +{
> + V2SI_d si = { 35, 42 };
> + id_V2SI(&si);
> +
> + if (si[0] != 35 || si[1] != 42)
> + abort();
> +
> + V2DI_d di = { 63, 38 };
> + id_V2DI(&di);
> +
> + if (di[0] != 63 || di[1] != 38)
> + abort();
> +}
