I'm gonna send a v2 of this patch with a different commit message.
Marek
On Wed, Jan 4, 2017 at 1:45 PM, Marek Olšák <mar...@gmail.com> wrote:
> Here's my theory about the Witcher 2 issue:
>
> The problematic shader contains KILL. Reloading inputs after KILL is
> unsafe, because KILL breaks the WQM mode, thus the inputs are not
> loaded for the whole quad. Control flow statements have a similar
> issue.
>
> These are the cases when inputs can be reloaded safely at each use:
>
> the shader doesn't use WQM ||
> (the reload doesn't take place inside a conditional block &&
> the reload is before KILL)
>
> Marek
>
> On Tue, Jan 3, 2017 at 8:17 PM, Marek Olšák <mar...@gmail.com> wrote:
>> From: Marek Olšák <marek.ol...@amd.com>
>>
>> ---
>> src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c | 15 +++++++++++++--
>> 1 file changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>> b/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>> index 996a458..efe28d1 100644
>> --- a/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>> +++ b/src/gallium/drivers/radeonsi/si_shader_tgsi_setup.c
>> @@ -629,20 +629,29 @@ store_value_to_array(struct lp_build_tgsi_context
>> *bld_base,
>> default:
>> continue;
>> }
>> value = LLVMBuildExtractElement(builder, array,
>> lp_build_const_int32(gallivm, i), "");
>> LLVMBuildStore(builder, value, temp_ptr);
>> }
>> }
>> }
>>
>> +/* If this is 1, preload FS inputs at the beginning of shaders. Otherwise,
>> + * reload them at each use.
>> + *
>> + * This must be 1 for Witcher 2 to render correctly. The cause of the
>> Witcher 2
>> + * issue is still unknown. I only know that M0 is correct throughout the
>> whole
>> + * shader.
>> + */
>> +#define SI_PRELOAD_FS_INPUTS 1
>> +
>> LLVMValueRef si_llvm_emit_fetch(struct lp_build_tgsi_context *bld_base,
>> const struct tgsi_full_src_register *reg,
>> enum tgsi_opcode_type type,
>> unsigned swizzle)
>> {
>> struct si_shader_context *ctx = si_shader_context(bld_base);
>> struct lp_build_tgsi_soa_context *bld = lp_soa_context(bld_base);
>> LLVMBuilderRef builder = bld_base->base.gallivm->builder;
>> LLVMValueRef result = NULL, ptr, ptr2;
>>
>> @@ -681,21 +690,22 @@ LLVMValueRef si_llvm_emit_fetch(struct
>> lp_build_tgsi_context *bld_base,
>>
>> case TGSI_FILE_INPUT: {
>> unsigned index = reg->Register.Index;
>> LLVMValueRef input[4];
>>
>> /* I don't think doing this for vertex shaders is beneficial.
>> * For those, we want to make sure the VMEM loads are
>> executed
>> * only once. Fragment shaders don't care much, because
>> * v_interp instructions are much cheaper than VMEM loads.
>> */
>> - if (ctx->soa.bld_base.info->processor ==
>> PIPE_SHADER_FRAGMENT)
>> + if (!SI_PRELOAD_FS_INPUTS &&
>> + ctx->soa.bld_base.info->processor ==
>> PIPE_SHADER_FRAGMENT)
>> ctx->load_input(ctx, index,
>> &ctx->input_decls[index], input);
>> else
>> memcpy(input, &ctx->inputs[index * 4],
>> sizeof(input));
>>
>> result = input[swizzle];
>>
>> if (tgsi_type_is_64bit(type)) {
>> ptr = result;
>> ptr2 = input[swizzle + 1];
>> return si_llvm_emit_fetch_64bit(bld_base, type, ptr,
>> ptr2);
>> @@ -874,21 +884,22 @@ static void emit_declaration(struct
>> lp_build_tgsi_context *bld_base,
>> {
>> unsigned idx;
>> for (idx = decl->Range.First; idx <= decl->Range.Last;
>> idx++) {
>> if (ctx->load_input &&
>> ctx->input_decls[idx].Declaration.File !=
>> TGSI_FILE_INPUT) {
>> ctx->input_decls[idx] = *decl;
>> ctx->input_decls[idx].Range.First = idx;
>> ctx->input_decls[idx].Range.Last = idx;
>> ctx->input_decls[idx].Semantic.Index += idx
>> - decl->Range.First;
>>
>> - if (bld_base->info->processor !=
>> PIPE_SHADER_FRAGMENT)
>> + if (SI_PRELOAD_FS_INPUTS ||
>> + bld_base->info->processor !=
>> PIPE_SHADER_FRAGMENT)
>> ctx->load_input(ctx, idx,
>> &ctx->input_decls[idx],
>> &ctx->inputs[idx *
>> 4]);
>> }
>> }
>> }
>> break;
>>
>> case TGSI_FILE_SYSTEM_VALUE:
>> {
>> unsigned idx;
>> --
>> 2.7.4
>>
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