[Mesa-dev] [PATCH] radeonsi: mark descriptor loads as using dynamically uniform indices

[Marek Olšák]

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

Marek

On Mon, May 2, 2016 at 11:24 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> This tells LLVM to always use SMEM loads for descriptors. It fixes a
> regression in piglit's arb_shader_storage_buffer_object/execution/indirect.shader_test
> that was caused by LLVM r268259 (but the proper fix is really here in Mesa).
> ---
>  src/gallium/drivers/radeonsi/si_shader.c | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
> index 1d6dc78..49c498d 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -94,7 +94,9 @@ struct si_shader_context
>
>         LLVMTargetMachineRef tm;
>
> +       unsigned uniform_md_kind;
>         LLVMValueRef const_md;
> +       LLVMValueRef empty_md;
>         LLVMValueRef const_buffers[SI_NUM_CONST_BUFFERS];
>         LLVMValueRef lds;
>         LLVMValueRef *constants[SI_NUM_CONST_BUFFERS];
> @@ -373,9 +375,12 @@ static void build_indexed_store(struct si_shader_context *ctx,
>   *
>   * \param base_ptr  Where the array starts.
>   * \param index     The element index into the array.
> + * \param uniform   Whether the base_ptr and index can be assumed to be
> + *                  dynamically uniform
>   */
>  static LLVMValueRef build_indexed_load(struct si_shader_context *ctx,
> -                                      LLVMValueRef base_ptr, LLVMValueRef index)
> +                                      LLVMValueRef base_ptr, LLVMValueRef index,
> +                                      bool uniform)
>  {
>         struct lp_build_tgsi_context *bld_base = &ctx->radeon_bld.soa.bld_base;
>         struct gallivm_state *gallivm = bld_base->base.gallivm;
> @@ -385,18 +390,20 @@ static LLVMValueRef build_indexed_load(struct si_shader_context *ctx,
>         indices[1] = index;
>
>         pointer = LLVMBuildGEP(gallivm->builder, base_ptr, indices, 2, "");
> +       if (uniform)
> +               LLVMSetMetadata(pointer, ctx->uniform_md_kind, ctx->empty_md);
>         return LLVMBuildLoad(gallivm->builder, pointer, "");
>  }
>
>  /**
>   * Do a load from &base_ptr[index], but also add a flag that it's loading
> - * a constant.
> + * a constant from a dynamically uniform index.
>   */
>  static LLVMValueRef build_indexed_load_const(
>         struct si_shader_context *ctx,
>         LLVMValueRef base_ptr, LLVMValueRef index)
>  {
> -       LLVMValueRef result = build_indexed_load(ctx, base_ptr, index);
> +       LLVMValueRef result = build_indexed_load(ctx, base_ptr, index, true);
>         LLVMSetMetadata(result, 1, ctx->const_md);
>         return result;
>  }
> @@ -679,12 +686,12 @@ static LLVMValueRef lds_load(struct lp_build_tgsi_context *bld_base,
>         dw_addr = lp_build_add(&bld_base->uint_bld, dw_addr,
>                             lp_build_const_int32(gallivm, swizzle));
>
> -       value = build_indexed_load(ctx, ctx->lds, dw_addr);
> +       value = build_indexed_load(ctx, ctx->lds, dw_addr, false);
>         if (type == TGSI_TYPE_DOUBLE) {
>                 LLVMValueRef value2;
>                 dw_addr = lp_build_add(&bld_base->uint_bld, dw_addr,
>                                        lp_build_const_int32(gallivm, swizzle + 1));
> -               value2 = build_indexed_load(ctx, ctx->lds, dw_addr);
> +               value2 = build_indexed_load(ctx, ctx->lds, dw_addr, false);
>                 return radeon_llvm_emit_fetch_double(bld_base, value, value2);
>         }
>
> @@ -4885,6 +4892,11 @@ static void create_meta_data(struct si_shader_context *ctx)
>         args[2] = lp_build_const_int32(gallivm, 1);
>
>         ctx->const_md = LLVMMDNodeInContext(gallivm->context, args, 3);
> +
> +       ctx->uniform_md_kind = LLVMGetMDKindIDInContext(gallivm->context,
> +                                                       "amdgpu.uniform", 14);
> +
> +       ctx->empty_md = LLVMMDNodeInContext(gallivm->context, NULL, 0);
>  }
>
>  static void declare_streamout_params(struct si_shader_context *ctx,
> --
> 2.7.4
>
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