[Mesa-dev] [PATCH 2/2] freedreno: ir3: fix wrong return if reg is an array

[Rob Clark]

On Tue, Oct 23, 2018 at 9:57 PM Hyunjun Ko <zzoon at igalia.com> wrote:
>
> Since ir3_register struct has union, it could return true even
> if it's an array register accidentally when checking whether it
> is address/predicate register.
>
> Fixes: dEQP-GLES31.functional.ssbo.layout.random.arrays_of_arrays.6
> ---
>  src/gallium/drivers/freedreno/ir3/ir3.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/freedreno/ir3/ir3.h b/src/gallium/drivers/freedreno/ir3/ir3.h
> index 3055c10f1d..db94603558 100644
> --- a/src/gallium/drivers/freedreno/ir3/ir3.h
> +++ b/src/gallium/drivers/freedreno/ir3/ir3.h
> @@ -739,7 +739,7 @@ static inline bool writes_addr(struct ir3_instruction *instr)
>  {
>         if (instr->regs_count > 0) {
>                 struct ir3_register *dst = instr->regs[0];
> -               return reg_num(dst) == REG_A0;
> +               return (reg_num(dst) == REG_A0) && !(dst->flags & IR3_REG_ARRAY);

hmm, good catch.. although I wonder if writes_gpr() in ir3_ra.c has
the same issue.  Or anywhere else?  (Otoh, I guess checking for CONST
and IMMED in writes_gpr() is a bit silly)

>From a quick look at the IR3_REG_* flags, I think IR3_REG_ARRAY is the
only problematic case.. but this is a bit more fragile than it should
be.  Maybe we should just move 'int num' out of the union?  Maybe that
was too much premature optimization?

BR,
-R

>         }
>         return false;
>  }
> @@ -748,7 +748,7 @@ static inline bool writes_pred(struct ir3_instruction *instr)
>  {
>         if (instr->regs_count > 0) {
>                 struct ir3_register *dst = instr->regs[0];
> -               return reg_num(dst) == REG_P0;
> +               return (reg_num(dst) == REG_P0) && !(dst->flags & IR3_REG_ARRAY);
>         }
>         return false;
>  }
> --
> 2.17.1
>