diff options
| author | Matt Turner <[email protected]> | 2014-10-28 20:12:21 -0700 |
|---|---|---|
| committer | Matt Turner <[email protected]> | 2014-12-01 16:42:13 -0800 |
| commit | 60d507c3c5c7caed57119df0ab4d824ad1ea85dc (patch) | |
| tree | 3ebe011a49ab74868eed3b78e8ed49872ef8eba2 /src/mesa/drivers/dri | |
| parent | bf8deb55146696b2332d9ea29f6242d236e1b46a (diff) | |
i965/fs: Dead code eliminate instructions writing the flag.
Most prominently helps Natural Selection 2, which has a surprising
number shaders that do very complicated things before drawing black.
instructions in affected programs: 21052 -> 16978 (-19.35%)
Reviewed-by: Kenneth Graunke <[email protected]>
Diffstat (limited to 'src/mesa/drivers/dri')
| -rw-r--r-- | src/mesa/drivers/dri/i965/brw_fs_dead_code_eliminate.cpp | 26 |
1 files changed, 22 insertions, 4 deletions
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 9cf8d89eef4..fa471829e8e 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 @@ -43,15 +43,16 @@ fs_visitor::dead_code_eliminate() int num_vars = live_intervals->num_vars; 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) { 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) { - if (inst->dst.file == GRF && - !inst->has_side_effects() && - !inst->writes_flag()) { + if (inst->dst.file == GRF && !inst->has_side_effects()) { bool result_live = false; if (inst->regs_written == 1) { @@ -67,7 +68,7 @@ fs_visitor::dead_code_eliminate() if (!result_live) { progress = true; - if (inst->writes_accumulator) { + if (inst->writes_accumulator || inst->writes_flag()) { inst->dst = fs_reg(retype(brw_null_reg(), inst->dst.type)); } else { inst->opcode = BRW_OPCODE_NOP; @@ -76,6 +77,14 @@ fs_visitor::dead_code_eliminate() } } + if (inst->dst.is_null() && inst->writes_flag()) { + if (!BITSET_TEST(flag_live, inst->flag_subreg)) { + inst->opcode = BRW_OPCODE_NOP; + progress = true; + continue; + } + } + if (inst->dst.file == GRF) { if (!inst->is_partial_write()) { int var = live_intervals->var_from_reg(&inst->dst); @@ -85,6 +94,10 @@ fs_visitor::dead_code_eliminate() } } + if (inst->writes_flag()) { + BITSET_CLEAR(flag_live, inst->flag_subreg); + } + for (int i = 0; i < inst->sources; i++) { if (inst->src[i].file == GRF) { int var = live_intervals->var_from_reg(&inst->src[i]); @@ -94,10 +107,15 @@ fs_visitor::dead_code_eliminate() } } } + + if (inst->reads_flag()) { + BITSET_SET(flag_live, inst->flag_subreg); + } } } ralloc_free(live); + ralloc_free(flag_live); if (progress) { foreach_block_and_inst_safe (block, backend_instruction, inst, cfg) { |