On Mon, May 16, 2016 at 7:48 PM, Marek Olšák <mar...@gmail.com> wrote:
> NAK. The barrier is never needed with tessellation, because every
> patch always fits into a single wave and there is no patch splitting
> between waves.
>
> Marek
OK.
I don't see any optimization barrier before loading the tess factors
though, is the part that added the barrier (now optimization barrier)
before loading the tess factors also NAKed?
- Bas
>
> On Fri, May 13, 2016 at 3:37 AM, Bas Nieuwenhuizen
> <b...@basnieuwenhuizen.nl> wrote:
>> With potentially more than 1 wave working on a patch we
>> need the barrier.
>>
>> Also adds a barrier before loading the tessellation factors to
>> write them to the TF ring.
>>
>> Signed-off-by: Bas Nieuwenhuizen <b...@basnieuwenhuizen.nl>
>> Reviewed-by: Nicolai Hähnle <nicolai.haeh...@amd.com>
>> ---
>> src/gallium/drivers/radeonsi/si_shader.c | 48
>> ++++++++++----------------------
>> 1 file changed, 15 insertions(+), 33 deletions(-)
>>
>> diff --git a/src/gallium/drivers/radeonsi/si_shader.c
>> b/src/gallium/drivers/radeonsi/si_shader.c
>> index 087b5bb..235983a 100644
>> --- a/src/gallium/drivers/radeonsi/si_shader.c
>> +++ b/src/gallium/drivers/radeonsi/si_shader.c
>> @@ -2514,6 +2514,19 @@ static void si_copy_tcs_inputs(struct
>> lp_build_tgsi_context *bld_base)
>> }
>> }
>>
>> +static void si_llvm_emit_barrier(const struct lp_build_tgsi_action *action,
>> + struct lp_build_tgsi_context *bld_base,
>> + struct lp_build_emit_data *emit_data)
>> +{
>> + struct si_shader_context *ctx = si_shader_context(bld_base);
>> + struct gallivm_state *gallivm = bld_base->base.gallivm;
>> +
>> + lp_build_intrinsic(gallivm->builder,
>> + HAVE_LLVM >= 0x0309 ? "llvm.amdgcn.s.barrier"
>> + : "llvm.AMDGPU.barrier.local",
>> + ctx->voidt, NULL, 0, LLVMNoUnwindAttribute);
>> +}
>> +
>> static void si_write_tess_factors(struct lp_build_tgsi_context *bld_base,
>> LLVMValueRef rel_patch_id,
>> LLVMValueRef invocation_id,
>> @@ -2528,6 +2541,8 @@ static void si_write_tess_factors(struct
>> lp_build_tgsi_context *bld_base,
>> unsigned stride, outer_comps, inner_comps, i;
>> struct lp_build_if_state if_ctx;
>>
>> + si_llvm_emit_barrier(NULL, bld_base, NULL);
>> +
>> /* Do this only for invocation 0, because the tess levels are
>> per-patch,
>> * not per-vertex.
>> *
>> @@ -3213,18 +3228,6 @@ static void build_tex_intrinsic(const struct
>> lp_build_tgsi_action *action,
>> struct lp_build_tgsi_context *bld_base,
>> struct lp_build_emit_data *emit_data);
>>
>> -/* Prevent optimizations (at least of memory accesses) across the current
>> - * point in the program by emitting empty inline assembly that is marked as
>> - * having side effects.
>> - */
>> -static void emit_optimization_barrier(struct si_shader_context *ctx)
>> -{
>> - LLVMBuilderRef builder = ctx->radeon_bld.gallivm.builder;
>> - LLVMTypeRef ftype = LLVMFunctionType(ctx->voidt, NULL, 0, false);
>> - LLVMValueRef inlineasm = LLVMConstInlineAsm(ftype, "", "", true,
>> false);
>> - LLVMBuildCall(builder, inlineasm, NULL, 0, "");
>> -}
>> -
>> static void emit_waitcnt(struct si_shader_context *ctx)
>> {
>> struct gallivm_state *gallivm = &ctx->radeon_bld.gallivm;
>> @@ -5154,27 +5157,6 @@ static void si_llvm_emit_primitive(
>> ctx->voidt, args, 2, LLVMNoUnwindAttribute);
>> }
>>
>> -static void si_llvm_emit_barrier(const struct lp_build_tgsi_action *action,
>> - struct lp_build_tgsi_context *bld_base,
>> - struct lp_build_emit_data *emit_data)
>> -{
>> - struct si_shader_context *ctx = si_shader_context(bld_base);
>> - struct gallivm_state *gallivm = bld_base->base.gallivm;
>> -
>> - /* The real barrier instruction isn’t needed, because an entire patch
>> - * always fits into a single wave.
>> - */
>> - if (ctx->type == PIPE_SHADER_TESS_CTRL) {
>> - emit_optimization_barrier(ctx);
>> - return;
>> - }
>> -
>> - lp_build_intrinsic(gallivm->builder,
>> - HAVE_LLVM >= 0x0309 ? "llvm.amdgcn.s.barrier"
>> - : "llvm.AMDGPU.barrier.local",
>> - ctx->voidt, NULL, 0, LLVMNoUnwindAttribute);
>> -}
>> -
>> static const struct lp_build_tgsi_action tex_action = {
>> .fetch_args = tex_fetch_args,
>> .emit = build_tex_intrinsic,
>> --
>> 2.8.2
>>
>> _______________________________________________
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>> mesa-dev@lists.freedesktop.org
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