Module: Mesa Branch: master Commit: 7e6a6f3e619e7dfed244043a95082f2168a5c953 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=7e6a6f3e619e7dfed244043a95082f2168a5c953
Author: Matt Turner <[email protected]> Date: Mon Nov 30 09:25:19 2015 -0800 i965: Do dead-code elimination in a single pass. The first pass marked dead instructions as opcode = NOP, and a second pass deleted those instructions so that the live ranges used in the first pass wouldn't change. But since we're walking the instructions in reverse order, we can just do everything in one pass. The only thing we have to do is walk the blocks in reverse as well. Reviewed-by: Francisco Jerez <[email protected]> --- src/mesa/drivers/dri/i965/brw_cfg.h | 3 +++ .../dri/i965/brw_fs_dead_code_eliminate.cpp | 21 ++++++-------------- .../dri/i965/brw_vec4_dead_code_eliminate.cpp | 21 +++++++------------- 3 files changed, 16 insertions(+), 29 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_cfg.h b/src/mesa/drivers/dri/i965/brw_cfg.h index 69e39e8..405020b 100644 --- a/src/mesa/drivers/dri/i965/brw_cfg.h +++ b/src/mesa/drivers/dri/i965/brw_cfg.h @@ -314,6 +314,9 @@ struct cfg_t { #define foreach_block_safe(__block, __cfg) \ foreach_list_typed_safe (bblock_t, __block, link, &(__cfg)->block_list) +#define foreach_block_reverse_safe(__block, __cfg) \ + foreach_list_typed_reverse_safe (bblock_t, __block, link, &(__cfg)->block_list) + #define foreach_inst_in_block(__type, __inst, __block) \ foreach_in_list(__type, __inst, &(__block)->instructions) diff --git a/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp b/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp index 6b4b602..bd57e09 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp @@ -45,13 +45,13 @@ fs_visitor::dead_code_eliminate() BITSET_WORD *live = ralloc_array(NULL, BITSET_WORD, BITSET_WORDS(num_vars)); BITSET_WORD *flag_live = ralloc_array(NULL, BITSET_WORD, 1); - foreach_block (block, cfg) { + foreach_block_reverse_safe(block, cfg) { memcpy(live, live_intervals->block_data[block->num].liveout, sizeof(BITSET_WORD) * BITSET_WORDS(num_vars)); memcpy(flag_live, live_intervals->block_data[block->num].flag_liveout, sizeof(BITSET_WORD)); - foreach_inst_in_block_reverse(fs_inst, inst, block) { + foreach_inst_in_block_reverse_safe(fs_inst, inst, block) { if (inst->dst.file == VGRF && !inst->has_side_effects()) { bool result_live = false; @@ -72,7 +72,6 @@ fs_visitor::dead_code_eliminate() inst->dst = fs_reg(retype(brw_null_reg(), inst->dst.type)); } else { inst->opcode = BRW_OPCODE_NOP; - continue; } } } @@ -81,7 +80,6 @@ fs_visitor::dead_code_eliminate() if (!BITSET_TEST(flag_live, inst->flag_subreg)) { inst->opcode = BRW_OPCODE_NOP; progress = true; - continue; } } @@ -93,7 +91,6 @@ fs_visitor::dead_code_eliminate() !inst->writes_accumulator) { inst->opcode = BRW_OPCODE_NOP; progress = true; - continue; } if (inst->dst.file == VGRF) { @@ -109,9 +106,10 @@ fs_visitor::dead_code_eliminate() BITSET_CLEAR(flag_live, inst->flag_subreg); } - /* Don't mark dead instructions' sources as live */ - if (inst->opcode == BRW_OPCODE_NOP) + if (inst->opcode == BRW_OPCODE_NOP) { + inst->remove(block); continue; + } for (int i = 0; i < inst->sources; i++) { if (inst->src[i].file == VGRF) { @@ -132,15 +130,8 @@ fs_visitor::dead_code_eliminate() ralloc_free(live); ralloc_free(flag_live); - if (progress) { - foreach_block_and_inst_safe (block, backend_instruction, inst, cfg) { - if (inst->opcode == BRW_OPCODE_NOP) { - inst->remove(block); - } - } - + if (progress) invalidate_live_intervals(); - } return progress; } diff --git a/src/mesa/drivers/dri/i965/brw_vec4_dead_code_eliminate.cpp b/src/mesa/drivers/dri/i965/brw_vec4_dead_code_eliminate.cpp index 369941b..2d0722a 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_dead_code_eliminate.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_dead_code_eliminate.cpp @@ -71,13 +71,13 @@ vec4_visitor::dead_code_eliminate() BITSET_WORD *live = ralloc_array(NULL, BITSET_WORD, BITSET_WORDS(num_vars)); BITSET_WORD *flag_live = ralloc_array(NULL, BITSET_WORD, 1); - foreach_block(block, cfg) { + foreach_block_reverse_safe(block, cfg) { memcpy(live, live_intervals->block_data[block->num].liveout, sizeof(BITSET_WORD) * BITSET_WORDS(num_vars)); memcpy(flag_live, live_intervals->block_data[block->num].flag_liveout, sizeof(BITSET_WORD)); - foreach_inst_in_block_reverse(vec4_instruction, inst, block) { + foreach_inst_in_block_reverse_safe(vec4_instruction, inst, block) { if ((inst->dst.file == VGRF && !inst->has_side_effects()) || (inst->dst.is_null() && inst->writes_flag())){ bool result_live[4] = { false }; @@ -115,7 +115,7 @@ vec4_visitor::dead_code_eliminate() inst->dst = dst_reg(retype(brw_null_reg(), inst->dst.type)); } else { inst->opcode = BRW_OPCODE_NOP; - continue; + break; } } } @@ -130,7 +130,6 @@ vec4_visitor::dead_code_eliminate() if (!combined_live) { inst->opcode = BRW_OPCODE_NOP; progress = true; - continue; } } @@ -150,9 +149,10 @@ vec4_visitor::dead_code_eliminate() BITSET_CLEAR(flag_live, c); } - /* Don't mark dead instructions' sources as live */ - if (inst->opcode == BRW_OPCODE_NOP) + if (inst->opcode == BRW_OPCODE_NOP) { + inst->remove(block); continue; + } for (int i = 0; i < 3; i++) { if (inst->src[i].file == VGRF) { @@ -176,15 +176,8 @@ vec4_visitor::dead_code_eliminate() ralloc_free(live); ralloc_free(flag_live); - if (progress) { - foreach_block_and_inst_safe(block, backend_instruction, inst, cfg) { - if (inst->opcode == BRW_OPCODE_NOP) { - inst->remove(block); - } - } - + if (progress) invalidate_live_intervals(); - } return progress; } _______________________________________________ mesa-commit mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-commit
