From 95b001cb190dbc0ec71d760e1d9c457c1a3e4f70 Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Mon, 11 Mar 2019 20:43:15 -0500 Subject: [PATCH 05/24] glsl/lower_vector_derefs: Don't use a temporary for TCS outputs Tessellation control shader outputs act as if they have memory backing them and you can have multiple writes to different components of the same vector in-flight at the same time. When this happens, the load vec store pattern that gets used by ir_triop_vector_insert doesn't yield the correct results. Instead, just emit a sequence of conditional assignments. Reviewed-by: Ian Romanick Cc: mesa-stable@lists.freedesktop.org (cherry picked from commit bd17bdc56b34a08c421172df27fe07294c7a7024) --- src/compiler/glsl/lower_vector_derefs.cpp | 74 ++++++++++++++++++++--- 1 file changed, 64 insertions(+), 10 deletions(-) diff --git a/src/compiler/glsl/lower_vector_derefs.cpp b/src/compiler/glsl/lower_vector_derefs.cpp index 6cd9a2d819a..2aae30d8201 100644 --- a/src/compiler/glsl/lower_vector_derefs.cpp +++ b/src/compiler/glsl/lower_vector_derefs.cpp @@ -32,8 +32,9 @@ namespace { class vector_deref_visitor : public ir_rvalue_enter_visitor { public: - vector_deref_visitor() - : progress(false) + vector_deref_visitor(void *mem_ctx, gl_shader_stage shader_stage) + : progress(false), shader_stage(shader_stage), + factory(&factory_instructions, mem_ctx) { } @@ -45,6 +46,9 @@ public: virtual ir_visitor_status visit_enter(ir_assignment *ir); bool progress; + gl_shader_stage shader_stage; + exec_list factory_instructions; + ir_factory factory; }; } /* anonymous namespace */ @@ -65,13 +69,63 @@ vector_deref_visitor::visit_enter(ir_assignment *ir) ir_constant *old_index_constant = deref->array_index->constant_expression_value(mem_ctx); if (!old_index_constant) { - ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert, - new_lhs->type, - new_lhs->clone(mem_ctx, NULL), - ir->rhs, - deref->array_index); - ir->write_mask = (1 << new_lhs->type->vector_elements) - 1; - ir->set_lhs(new_lhs); + if (shader_stage == MESA_SHADER_TESS_CTRL && + deref->variable_referenced()->data.mode == ir_var_shader_out) { + /* Tessellation control shader outputs act as if they have memory + * backing them and if we have writes from multiple threads + * targeting the same vec4 (this can happen for patch outputs), the + * load-vec-store pattern of ir_triop_vector_insert doesn't work. + * Instead, we have to lower to a series of conditional write-masked + * assignments. + */ + ir_variable *const src_temp = + factory.make_temp(ir->rhs->type, "scalar_tmp"); + + /* The newly created variable declaration goes before the assignment + * because we're going to set it as the new LHS. + */ + ir->insert_before(factory.instructions); + ir->set_lhs(new(mem_ctx) ir_dereference_variable(src_temp)); + + ir_variable *const arr_index = + factory.make_temp(deref->array_index->type, "index_tmp"); + factory.emit(assign(arr_index, deref->array_index)); + + for (unsigned i = 0; i < new_lhs->type->vector_elements; i++) { + ir_constant *const cmp_index = + ir_constant::zero(factory.mem_ctx, deref->array_index->type); + cmp_index->value.u[0] = i; + + ir_rvalue *const lhs_clone = new_lhs->clone(factory.mem_ctx, NULL); + ir_dereference_variable *const src_temp_deref = + new(mem_ctx) ir_dereference_variable(src_temp); + + if (new_lhs->ir_type != ir_type_swizzle) { + assert(lhs_clone->as_dereference()); + ir_assignment *cond_assign = + new(mem_ctx) ir_assignment(lhs_clone->as_dereference(), + src_temp_deref, + equal(arr_index, cmp_index), + WRITEMASK_X << i); + factory.emit(cond_assign); + } else { + ir_assignment *cond_assign = + new(mem_ctx) ir_assignment(swizzle(lhs_clone, i, 1), + src_temp_deref, + equal(arr_index, cmp_index)); + factory.emit(cond_assign); + } + } + ir->insert_after(factory.instructions); + } else { + ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert, + new_lhs->type, + new_lhs->clone(mem_ctx, NULL), + ir->rhs, + deref->array_index); + ir->write_mask = (1 << new_lhs->type->vector_elements) - 1; + ir->set_lhs(new_lhs); + } } else if (new_lhs->ir_type != ir_type_swizzle) { ir->set_lhs(new_lhs); ir->write_mask = 1 << old_index_constant->get_uint_component(0); @@ -105,7 +159,7 @@ vector_deref_visitor::handle_rvalue(ir_rvalue **rv) bool lower_vector_derefs(gl_linked_shader *shader) { - vector_deref_visitor v; + vector_deref_visitor v(shader->ir, shader->Stage); visit_list_elements(&v, shader->ir); -- 2.21.0