From 7655bccce80c9690ecb850304d15238ef1e0d622 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Nicolai=20H=C3=A4hnle?= Date: Tue, 29 Nov 2016 16:33:31 +0100 Subject: [PATCH] radeonsi: do not kill GS with memory writes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Vertex emits beyond the specified maximum number of vertices are supposed to have no effect, which is why we used to always kill GS that reached the limit. However, if the GS also writes to memory (SSBO, atomics, shader images), then we must keep going and only skip the vertex emit itself. Cc: mesa-stable@lists.freedesktop.org Reviewed-by: Marek Olšák --- src/gallium/drivers/radeonsi/si_shader.c | 30 +++++++++++++++++------- 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c index 9560baf7961..8827643caef 100644 --- a/src/gallium/drivers/radeonsi/si_shader.c +++ b/src/gallium/drivers/radeonsi/si_shader.c @@ -5256,6 +5256,7 @@ static void si_llvm_emit_vertex( struct si_shader *shader = ctx->shader; struct tgsi_shader_info *info = &shader->selector->info; struct gallivm_state *gallivm = bld_base->base.gallivm; + struct lp_build_if_state if_state; LLVMValueRef soffset = LLVMGetParam(ctx->main_fn, SI_PARAM_GS2VS_OFFSET); LLVMValueRef gs_next_vertex; @@ -5273,19 +5274,28 @@ static void si_llvm_emit_vertex( ""); /* If this thread has already emitted the declared maximum number of - * vertices, kill it: excessive vertex emissions are not supposed to - * have any effect, and GS threads have no externally observable - * effects other than emitting vertices. + * vertices, skip the write: excessive vertex emissions are not + * supposed to have any effect. + * + * If the shader has no writes to memory, kill it instead. This skips + * further memory loads and may allow LLVM to skip to the end + * altogether. */ can_emit = LLVMBuildICmp(gallivm->builder, LLVMIntULE, gs_next_vertex, lp_build_const_int32(gallivm, shader->selector->gs_max_out_vertices), ""); - kill = lp_build_select(&bld_base->base, can_emit, - lp_build_const_float(gallivm, 1.0f), - lp_build_const_float(gallivm, -1.0f)); - lp_build_intrinsic(gallivm->builder, "llvm.AMDGPU.kill", - ctx->voidt, &kill, 1, 0); + bool use_kill = !info->writes_memory; + if (use_kill) { + kill = lp_build_select(&bld_base->base, can_emit, + lp_build_const_float(gallivm, 1.0f), + lp_build_const_float(gallivm, -1.0f)); + + lp_build_intrinsic(gallivm->builder, "llvm.AMDGPU.kill", + ctx->voidt, &kill, 1, 0); + } else { + lp_build_if(&if_state, gallivm, can_emit); + } for (i = 0; i < info->num_outputs; i++) { LLVMValueRef *out_ptr = @@ -5311,6 +5321,7 @@ static void si_llvm_emit_vertex( 1, 0, 1, 1, 0); } } + gs_next_vertex = lp_build_add(uint, gs_next_vertex, lp_build_const_int32(gallivm, 1)); @@ -5321,6 +5332,9 @@ static void si_llvm_emit_vertex( args[1] = LLVMGetParam(ctx->main_fn, SI_PARAM_GS_WAVE_ID); lp_build_intrinsic(gallivm->builder, "llvm.SI.sendmsg", ctx->voidt, args, 2, 0); + + if (!use_kill) + lp_build_endif(&if_state); } /* Cut one primitive from the geometry shader */ -- 2.30.2