[Mesa-dev] [PATCH 43/61] radeonsi/gfx9: add GS prolog support for merged ES-GS

Nicolai Hähnle nhaehnle at gmail.com
Fri Apr 28 11:25:33 UTC 2017


On 24.04.2017 10:45, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> ---
>  src/gallium/drivers/radeonsi/si_shader.c | 87 +++++++++++++++++++++++++-------
>  1 file changed, 70 insertions(+), 17 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
> index a4c2ac0..392f85d 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -7368,20 +7368,28 @@ static void si_count_scratch_private_memory(struct si_shader_context *ctx)
>  			LLVMTypeRef type = LLVMGetElementType(LLVMTypeOf(inst));
>  			/* No idea why LLVM aligns allocas to 4 elements. */
>  			unsigned alignment = LLVMGetAlignment(inst);
>  			unsigned dw_size = align(llvm_get_type_size(type) / 4, alignment);
>  			ctx->shader->config.private_mem_vgprs += dw_size;
>  		}
>  		bb = LLVMGetNextBasicBlock(bb);
>  	}
>  }
>
> +static void si_init_exec_full_mask(struct si_shader_context *ctx)
> +{
> +	LLVMValueRef full_mask = LLVMConstInt(ctx->i64, ~0ull, 0);
> +	lp_build_intrinsic(ctx->gallivm.builder,
> +			   "llvm.amdgcn.init.exec", ctx->voidt,
> +			   &full_mask, 1, LP_FUNC_ATTR_CONVERGENT);
> +}
> +
>  static void si_init_exec_from_input(struct si_shader_context *ctx,
>  				    unsigned param, unsigned bitoffset)
>  {
>  	LLVMValueRef args[] = {
>  		LLVMGetParam(ctx->main_fn, param),
>  		LLVMConstInt(ctx->i32, bitoffset, 0),
>  	};
>  	lp_build_intrinsic(ctx->gallivm.builder,
>  			   "llvm.amdgcn.init.exec.from.input",
>  			   ctx->voidt, args, 2, LP_FUNC_ATTR_CONVERGENT);
> @@ -7681,79 +7689,128 @@ static void si_get_ps_epilog_key(struct si_shader *shader,
>  	key->ps_epilog.states = shader->key.part.ps.epilog;
>  }
>
>  /**
>   * Build the GS prolog function. Rotate the input vertices for triangle strips
>   * with adjacency.
>   */
>  static void si_build_gs_prolog_function(struct si_shader_context *ctx,
>  					union si_shader_part_key *key)
>  {
> -	const unsigned num_sgprs = GFX6_GS_NUM_USER_SGPR + 2;
> -	const unsigned num_vgprs = 8;
> +	unsigned num_sgprs, num_vgprs;
>  	struct gallivm_state *gallivm = &ctx->gallivm;
>  	LLVMBuilderRef builder = gallivm->builder;
> -	LLVMTypeRef params[32];
> -	LLVMTypeRef returns[32];
> +	LLVMTypeRef params[48]; /* 40 SGPRs (maximum) + some VGPRs */
> +	LLVMTypeRef returns[48];
>  	LLVMValueRef func, ret;
>
> +	if (ctx->screen->b.chip_class >= GFX9) {
> +		num_sgprs = 8 + GFX9_GS_NUM_USER_SGPR;
> +		num_vgprs = 5; /* ES inputs are not needed by GS */
> +	} else {
> +		num_sgprs = GFX6_GS_NUM_USER_SGPR + 2;
> +		num_vgprs = 8;
> +	}
> +
>  	for (unsigned i = 0; i < num_sgprs; ++i) {
>  		params[i] = ctx->i32;
>  		returns[i] = ctx->i32;
>  	}
>
>  	for (unsigned i = 0; i < num_vgprs; ++i) {
>  		params[num_sgprs + i] = ctx->i32;
>  		returns[num_sgprs + i] = ctx->f32;
>  	}
>
>  	/* Create the function. */
>  	si_create_function(ctx, "gs_prolog", returns, num_sgprs + num_vgprs,
>  			   params, num_sgprs + num_vgprs, num_sgprs - 1);
>  	func = ctx->main_fn;
>
> +	/* Set the full EXEC mask for the prolog, because we are only fiddling
> +	 * with registers here. The main shader part will set the correct EXEC
> +	 * mask.
> +	 */
> +	if (ctx->screen->b.chip_class >= GFX9)
> +		si_init_exec_full_mask(ctx);
> +
>  	/* Copy inputs to outputs. This should be no-op, as the registers match,
>  	 * but it will prevent the compiler from overwriting them unintentionally.
>  	 */
>  	ret = ctx->return_value;
>  	for (unsigned i = 0; i < num_sgprs; i++) {
>  		LLVMValueRef p = LLVMGetParam(func, i);
>  		ret = LLVMBuildInsertValue(builder, ret, p, i, "");
>  	}
>  	for (unsigned i = 0; i < num_vgprs; i++) {
>  		LLVMValueRef p = LLVMGetParam(func, num_sgprs + i);
>  		p = LLVMBuildBitCast(builder, p, ctx->f32, "");
>  		ret = LLVMBuildInsertValue(builder, ret, p, num_sgprs + i, "");
>  	}
>
>  	if (key->gs_prolog.states.tri_strip_adj_fix) {
>  		/* Remap the input vertices for every other primitive. */
> -		const unsigned vtx_params[6] = {
> +		const unsigned gfx6_vtx_params[6] = {
>  			num_sgprs,
>  			num_sgprs + 1,
>  			num_sgprs + 3,
>  			num_sgprs + 4,
>  			num_sgprs + 5,
>  			num_sgprs + 6
>  		};
> +		const unsigned gfx9_vtx_params[3] = {
> +			num_sgprs,
> +			num_sgprs + 1,
> +			num_sgprs + 4,
> +		};
> +		LLVMValueRef vtx_in[6], vtx_out[6];
>  		LLVMValueRef prim_id, rotate;
>
> +		if (ctx->screen->b.chip_class >= GFX9) {
> +			for (unsigned i = 0; i < 3; i++) {
> +				vtx_in[i*2] = unpack_param(ctx, gfx9_vtx_params[i], 0, 16);
> +				vtx_in[i*2+1] = unpack_param(ctx, gfx9_vtx_params[i], 16, 16);
> +			}
> +		} else {
> +			for (unsigned i = 0; i < 6; i++)
> +				vtx_in[i] = LLVMGetParam(func, gfx6_vtx_params[i]);
> +		}
> +
>  		prim_id = LLVMGetParam(func, num_sgprs + 2);
>  		rotate = LLVMBuildTrunc(builder, prim_id, ctx->i1, "");
>
>  		for (unsigned i = 0; i < 6; ++i) {
> -			LLVMValueRef base, rotated, actual;
> -			base = LLVMGetParam(func, vtx_params[i]);
> -			rotated = LLVMGetParam(func, vtx_params[(i + 4) % 6]);
> -			actual = LLVMBuildSelect(builder, rotate, rotated, base, "");
> -			actual = LLVMBuildBitCast(builder, actual, ctx->f32, "");
> -			ret = LLVMBuildInsertValue(builder, ret, actual, vtx_params[i], "");
> +			LLVMValueRef base, rotated;
> +			base = vtx_in[i];
> +			rotated = vtx_in[(i + 4) % 6];
> +			vtx_out[i] = LLVMBuildSelect(builder, rotate, rotated, base, "");
> +		}
> +
> +		if (ctx->screen->b.chip_class >= GFX9) {
> +			for (unsigned i = 0; i < 3; i++) {
> +				LLVMValueRef hi, out;
> +
> +				hi = LLVMBuildShl(builder, vtx_out[i*2+1],
> +						  LLVMConstInt(ctx->i32, 16, 0), "");
> +				out = LLVMBuildOr(builder, vtx_out[i*2], hi, "");
> +				out = LLVMBuildBitCast(builder, out, ctx->f32, "");
> +				ret = LLVMBuildInsertValue(builder, ret, out,
> +							   gfx9_vtx_params[i], "");
> +			}
> +		} else {
> +			for (unsigned i = 0; i < 6; i++) {
> +				LLVMValueRef out;
> +
> +				out = LLVMBuildBitCast(builder, vtx_out[i], ctx->f32, "");
> +				ret = LLVMBuildInsertValue(builder, ret, out,
> +							   gfx6_vtx_params[i], "");
> +			}
>  		}

I believe this could be simplified quite a bit, since the vertex indices 
are rotate by a multiple of 2. So there's no need to unpack the bits and 
pack them again, instead just rotate the 3 input registers by 2 instead 
of rotating 6 input registers by 4.

I'm fine with it if you want to do that in a follow-up patch.

Cheers,
Nicolai


>  	}
>
>  	LLVMBuildRet(builder, ret);
>  }
>
>  /**
>   * Given a list of shader part functions, build a wrapper function that
>   * runs them in sequence to form a monolithic shader.
>   */
> @@ -7821,26 +7878,22 @@ static void si_build_wrapper_function(struct si_shader_context *ctx,
>
>  		assert(ac_is_sgpr_param(param) == (gprs < num_sgprs));
>  		assert(gprs + size <= num_sgprs + num_vgprs &&
>  		       (gprs >= num_sgprs || gprs + size <= num_sgprs));
>
>  		gprs += size;
>  	}
>
>  	si_create_function(ctx, "wrapper", NULL, 0, param_types, num_params, last_sgpr_param);
>
> -	if (is_merged_shader(ctx->shader)) {
> -		LLVMValueRef full_mask = LLVMConstInt(ctx->i64, ~0ull, 0);
> -		lp_build_intrinsic(ctx->gallivm.builder,
> -				   "llvm.amdgcn.init.exec", ctx->voidt,
> -				   &full_mask, 1, LP_FUNC_ATTR_CONVERGENT);
> -	}
> +	if (is_merged_shader(ctx->shader))
> +		si_init_exec_full_mask(ctx);
>
>  	/* Record the arguments of the function as if they were an output of
>  	 * a previous part.
>  	 */
>  	num_out = 0;
>  	num_out_sgpr = 0;
>
>  	for (unsigned i = 0; i < num_params; ++i) {
>  		LLVMValueRef param = LLVMGetParam(ctx->main_fn, i);
>  		LLVMTypeRef param_type = LLVMTypeOf(param);
>


-- 
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.


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