From: Matt Turner Date: Wed, 30 Oct 2013 17:32:12 +0000 (-0700) Subject: i965: Add a pass to remove dead control flow. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a97cd0f4d7902965d5173f4bcbf2ad27c0eb5d12;p=mesa.git i965: Add a pass to remove dead control flow. Removes IF/ENDIF and IF/ELSE/ENDIF with no intervening instructions. total instructions in shared programs: 1360393 -> 1360387 (-0.00%) instructions in affected programs: 157 -> 151 (-3.82%) (no change in vertex shaders) Reviewed-by: Paul Berry Reviewed-by: Eric Anholt Reviewed-by: Kenneth Graunke --- diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources index 572445829af..ac1363c776b 100644 --- a/src/mesa/drivers/dri/i965/Makefile.sources +++ b/src/mesa/drivers/dri/i965/Makefile.sources @@ -44,6 +44,7 @@ i965_FILES = \ brw_context.c \ brw_cubemap_normalize.cpp \ brw_curbe.c \ + brw_dead_control_flow.cpp \ brw_device_info.c \ brw_disasm.c \ brw_draw.c \ diff --git a/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp b/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp new file mode 100644 index 00000000000..8bdf0943e2e --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp @@ -0,0 +1,83 @@ +/* + * Copyright © 2013 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 brw_dead_control_flow.cpp + * + * This file implements the dead control flow elimination optimization pass. + */ + +#include "brw_shader.h" +#include "brw_cfg.h" + +/* Look for and eliminate dead control flow: + * + * - if/endif + * - if/else/endif + */ +bool +dead_control_flow_eliminate(backend_visitor *v) +{ + bool progress = false; + + cfg_t cfg(v); + + for (int b = 0; b < cfg.num_blocks; b++) { + bblock_t *block = cfg.blocks[b]; + bool found = false; + + /* ENDIF instructions, by definition, can only be found at the ends of + * basic blocks. + */ + backend_instruction *endif_inst = block->end; + if (endif_inst->opcode != BRW_OPCODE_ENDIF) + continue; + + backend_instruction *if_inst = NULL, *else_inst = NULL; + backend_instruction *prev_inst = (backend_instruction *) endif_inst->prev; + if (prev_inst->opcode == BRW_OPCODE_IF) { + if_inst = prev_inst; + found = true; + } else if (prev_inst->opcode == BRW_OPCODE_ELSE) { + else_inst = prev_inst; + + prev_inst = (backend_instruction *) prev_inst->prev; + if (prev_inst->opcode == BRW_OPCODE_IF) { + if_inst = prev_inst; + found = true; + } + } + + if (found) { + if_inst->remove(); + if (else_inst) + else_inst->remove(); + endif_inst->remove(); + progress = true; + } + } + + if (progress) + v->invalidate_live_intervals(); + + return progress; +} diff --git a/src/mesa/drivers/dri/i965/brw_dead_control_flow.h b/src/mesa/drivers/dri/i965/brw_dead_control_flow.h new file mode 100644 index 00000000000..57a4dabc83c --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_dead_control_flow.h @@ -0,0 +1,26 @@ +/* + * Copyright © 2013 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. + */ + +#include "brw_shader.h" + +bool dead_control_flow_eliminate(backend_visitor *v); diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 5b20b1cbbe6..d004521facd 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -46,6 +46,7 @@ extern "C" { #include "brw_wm.h" } #include "brw_fs.h" +#include "brw_dead_control_flow.h" #include "main/uniforms.h" #include "brw_fs_live_variables.h" #include "glsl/glsl_types.h" @@ -3264,6 +3265,7 @@ fs_visitor::run() progress = opt_copy_propagate() || progress; progress = dead_code_eliminate() || progress; progress = dead_code_eliminate_local() || progress; + progress = dead_control_flow_eliminate(this) || progress; progress = register_coalesce() || progress; progress = register_coalesce_2() || progress; progress = compute_to_mrf() || progress; diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp index e7cfab2e368..73f91a06281 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp @@ -24,6 +24,7 @@ #include "brw_vec4.h" #include "brw_cfg.h" #include "brw_vs.h" +#include "brw_dead_control_flow.h" extern "C" { #include "main/macros.h" @@ -1498,6 +1499,7 @@ vec4_visitor::run() do { progress = false; progress = dead_code_eliminate() || progress; + progress = dead_control_flow_eliminate(this) || progress; progress = opt_copy_propagation() || progress; progress = opt_algebraic() || progress; progress = opt_register_coalesce() || progress;