[Mesa-dev] [PATCH] st_glsl_to_tgsi: check for the tail sentinel in merge_two_dsts

[Marek Olšák]

Acked-by: Marek Olšák <marek.olsak at amd.com>

Marek

On Mon, Nov 20, 2017 at 4:36 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> This fixes yet another case where DFRACEXP has only one destination. Found
> by address sanitizer.
>
> Fixes tests/spec/arb_gpu_shader_fp64/execution/built-in-functions/fs-frexp-dvec4-only-mantissa.shader_test
>
> Fixes: 3b666aa74795 ("st/glsl_to_tgsi: fix DFRACEXP with only one destination")
> ---
>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> index 0772b736275..fa51fef343b 100644
> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> @@ -5245,32 +5245,32 @@ glsl_to_tgsi_visitor::merge_two_dsts(void)
>
>        assert(inst->dst[0].file != PROGRAM_UNDEFINED ||
>               inst->dst[1].file != PROGRAM_UNDEFINED);
>
>        if (inst->dst[0].file == PROGRAM_UNDEFINED)
>           defined = 1;
>        else
>           defined = 0;
>
>        inst2 = (glsl_to_tgsi_instruction *) inst->next;
> -      do {
> +      while (!inst2->is_tail_sentinel()) {
>           if (inst->op == inst2->op &&
>               inst2->dst[defined].file == PROGRAM_UNDEFINED &&
>               inst->src[0].file == inst2->src[0].file &&
>               inst->src[0].index == inst2->src[0].index &&
>               inst->src[0].type == inst2->src[0].type &&
>               inst->src[0].swizzle == inst2->src[0].swizzle)
>              break;
>           inst2 = (glsl_to_tgsi_instruction *) inst2->next;
> -      } while (inst2);
> +      }
>
> -      if (!inst2) {
> +      if (inst2->is_tail_sentinel()) {
>           /* Undefined destinations are not allowed, substitute with an unused
>            * temporary register.
>            */
>           st_src_reg tmp = get_temp(glsl_type::vec4_type);
>           inst->dst[defined ^ 1] = st_dst_reg(tmp);
>           inst->dst[defined ^ 1].writemask = 0;
>           continue;
>        }
>
>        inst->dst[defined ^ 1] = inst2->dst[defined ^ 1];
> --
> 2.11.0
>
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