[Mesa-dev] [PATCH 05/10] nir/from_ssa: Don't try to read an invalid instruction

[Connor Abbott]

Could use a comment here explaining that nir_instr_prev() may return
NULL above if the only instruction in the block is a jump instruction.

On Thu, Feb 5, 2015 at 5:29 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> ---
>  src/glsl/nir/nir_from_ssa.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/glsl/nir/nir_from_ssa.c b/src/glsl/nir/nir_from_ssa.c
> index 2e7add3..2ac114d 100644
> --- a/src/glsl/nir/nir_from_ssa.c
> +++ b/src/glsl/nir/nir_from_ssa.c
> @@ -277,7 +277,7 @@ get_parallel_copy_at_end_of_block(nir_block *block)
>     if (last_instr->type == nir_instr_type_jump)
>        last_instr = nir_instr_prev(last_instr);
>
> -   if (last_instr->type == nir_instr_type_parallel_copy)
> +   if (last_instr && last_instr->type == nir_instr_type_parallel_copy)
>        return nir_instr_as_parallel_copy(last_instr);
>     else
>        return NULL;
> --
> 2.2.2
>
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