From: Matt Turner Date: Wed, 23 Oct 2013 00:51:28 +0000 (-0700) Subject: i965/fs: New peephole optimization to flatten IF/BREAK/ENDIF. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d30b2ed5f83841531b4c5aa21bde50acad35560a;p=mesa.git i965/fs: New peephole optimization to flatten IF/BREAK/ENDIF. total instructions in shared programs: 1550713 -> 1550449 (-0.02%) instructions in affected programs: 7931 -> 7667 (-3.33%) Reviewed-by: Paul Berry --- diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources index 6e94dcab24b..43f152e4d45 100644 --- a/src/mesa/drivers/dri/i965/Makefile.sources +++ b/src/mesa/drivers/dri/i965/Makefile.sources @@ -60,6 +60,7 @@ i965_FILES = \ brw_fs_fp.cpp \ brw_fs_generator.cpp \ brw_fs_live_variables.cpp \ + brw_fs_peephole_predicated_break.cpp \ brw_fs_reg_allocate.cpp \ brw_fs_sel_peephole.cpp \ brw_fs_vector_splitting.cpp \ diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 3a363a81cff..00dbe318cc3 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -3172,6 +3172,7 @@ fs_visitor::run() progress = opt_cse() || progress; progress = opt_copy_propagate() || progress; progress = opt_peephole_sel() || progress; + progress = opt_peephole_predicated_break() || progress; progress = dead_code_eliminate() || progress; progress = dead_code_eliminate_local() || progress; progress = dead_control_flow_eliminate(this) || progress; diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h index 19f36923aee..2949c47118f 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.h +++ b/src/mesa/drivers/dri/i965/brw_fs.h @@ -364,6 +364,7 @@ public: bool try_emit_mad(ir_expression *ir, int mul_arg); void try_replace_with_sel(); bool opt_peephole_sel(); + bool opt_peephole_predicated_break(); void emit_bool_to_cond_code(ir_rvalue *condition); void emit_if_gen6(ir_if *ir); void emit_unspill(fs_inst *inst, fs_reg reg, uint32_t spill_offset, diff --git a/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp new file mode 100644 index 00000000000..bb0a2ac09a1 --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_fs_peephole_predicated_break.cpp @@ -0,0 +1,96 @@ +/* + * 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_fs.h" +#include "brw_cfg.h" + +/** @file brw_fs_peephole_predicated_break.cpp + * + * Loops are often structured as + * + * loop: + * CMP.f0 + * (+f0) IF + * BREAK + * ENDIF + * ... + * WHILE loop + * + * This peephole pass removes the IF and ENDIF instructions and predicates the + * BREAK, dropping two instructions from the loop body. + */ + +bool +fs_visitor::opt_peephole_predicated_break() +{ + bool progress = false; + + cfg_t cfg(&instructions); + + for (int b = 0; b < cfg.num_blocks; b++) { + bblock_t *block = cfg.blocks[b]; + + /* BREAK and CONTINUE instructions, by definition, can only be found at + * the ends of basic blocks. + */ + fs_inst *inst = (fs_inst *) block->end; + if (inst->opcode != BRW_OPCODE_BREAK && inst->opcode != BRW_OPCODE_CONTINUE) + continue; + + fs_inst *if_inst = (fs_inst *) inst->prev; + if (if_inst->opcode != BRW_OPCODE_IF) + continue; + + fs_inst *endif_inst = (fs_inst *) inst->next; + if (endif_inst->opcode != BRW_OPCODE_ENDIF) + continue; + + /* For Sandybridge with IF with embedded comparison we need to emit an + * instruction to set the flag register. + */ + if (brw->gen == 6 && if_inst->conditional_mod) { + fs_inst *cmp_inst = CMP(reg_null_d, if_inst->src[0], if_inst->src[1], + if_inst->conditional_mod); + if_inst->insert_before(cmp_inst); + inst->predicate = BRW_PREDICATE_NORMAL; + } else { + inst->predicate = if_inst->predicate; + inst->predicate_inverse = if_inst->predicate_inverse; + } + + if_inst->remove(); + endif_inst->remove(); + + /* By removing the ENDIF instruction we removed a basic block. Skip over + * it for the next iteration. + */ + b++; + + progress = true; + } + + if (progress) + invalidate_live_intervals(); + + return progress; +}