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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_discard_flow.cpp | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_discard_flow.cpp')
-rw-r--r-- | third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_discard_flow.cpp | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_discard_flow.cpp b/third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_discard_flow.cpp new file mode 100644 index 0000000000..1a30afe7c1 --- /dev/null +++ b/third_party/rust/glslopt/glsl-optimizer/src/compiler/glsl/lower_discard_flow.cpp @@ -0,0 +1,154 @@ +/* + * Copyright © 2010 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +/** @file lower_discard_flow.cpp + * + * Implements the GLSL 1.30 revision 9 rule for fragment shader + * discard handling: + * + * "Control flow exits the shader, and subsequent implicit or + * explicit derivatives are undefined when this control flow is + * non-uniform (meaning different fragments within the primitive + * take different control paths)." + * + * There seem to be two conflicting things here. "Control flow exits + * the shader" sounds like the discarded fragments should effectively + * jump to the end of the shader, but that breaks derivatives in the + * case of uniform control flow and causes rendering failure in the + * bushes in Unigine Tropics. + * + * The question, then, is whether the intent was "loops stop at the + * point that the only active channels left are discarded pixels" or + * "discarded pixels become inactive at the point that control flow + * returns to the top of a loop". This implements the second + * interpretation. + */ + +#include "compiler/glsl_types.h" +#include "ir.h" + +namespace { + +class lower_discard_flow_visitor : public ir_hierarchical_visitor { +public: + lower_discard_flow_visitor(ir_variable *discarded) + : discarded(discarded) + { + mem_ctx = ralloc_parent(discarded); + } + + ~lower_discard_flow_visitor() + { + } + + ir_visitor_status visit(ir_loop_jump *ir); + ir_visitor_status visit_enter(ir_discard *ir); + ir_visitor_status visit_enter(ir_loop *ir); + ir_visitor_status visit_enter(ir_function_signature *ir); + + ir_if *generate_discard_break(); + + ir_variable *discarded; + void *mem_ctx; +}; + +} /* anonymous namespace */ + +ir_visitor_status +lower_discard_flow_visitor::visit(ir_loop_jump *ir) +{ + if (ir->mode != ir_loop_jump::jump_continue) + return visit_continue; + + ir->insert_before(generate_discard_break()); + + return visit_continue; +} + +ir_visitor_status +lower_discard_flow_visitor::visit_enter(ir_discard *ir) +{ + ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(discarded); + ir_rvalue *rhs; + if (ir->condition) { + /* discarded <- condition, use (var_ref discarded) as the condition */ + rhs = ir->condition; + ir->condition = new(mem_ctx) ir_dereference_variable(discarded); + } else { + rhs = new(mem_ctx) ir_constant(true); + } + ir_assignment *assign = new(mem_ctx) ir_assignment(lhs, rhs); + ir->insert_before(assign); + + return visit_continue; +} + +ir_visitor_status +lower_discard_flow_visitor::visit_enter(ir_loop *ir) +{ + ir->body_instructions.push_tail(generate_discard_break()); + + return visit_continue; +} + +ir_visitor_status +lower_discard_flow_visitor::visit_enter(ir_function_signature *ir) +{ + if (strcmp(ir->function_name(), "main") != 0) + return visit_continue; + + ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(discarded); + ir_rvalue *rhs = new(mem_ctx) ir_constant(false); + ir_assignment *assign = new(mem_ctx) ir_assignment(lhs, rhs); + ir->body.push_head(assign); + + return visit_continue; +} + +ir_if * +lower_discard_flow_visitor::generate_discard_break() +{ + ir_rvalue *if_condition = new(mem_ctx) ir_dereference_variable(discarded); + ir_if *if_inst = new(mem_ctx) ir_if(if_condition); + + ir_instruction *br = new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_break); + if_inst->then_instructions.push_tail(br); + + return if_inst; +} + +void +lower_discard_flow(exec_list *ir) +{ + void *mem_ctx = ir; + + ir_variable *var = new(mem_ctx) ir_variable(glsl_type::bool_type, + "discarded", + ir_var_temporary); + + ir->push_head(var); + + lower_discard_flow_visitor v(var); + + visit_list_elements(&v, ir); +} |