diff options
Diffstat (limited to 'src/glsl/nir')
| -rw-r--r-- | src/glsl/nir/nir.h | 2 | ||||
| -rw-r--r-- | src/glsl/nir/nir_opt_undef.c | 104 |
2 files changed, 106 insertions, 0 deletions
diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h index 9aae6d70354..222a219d0e6 100644 --- a/src/glsl/nir/nir.h +++ b/src/glsl/nir/nir.h @@ -1704,6 +1704,8 @@ bool nir_opt_peephole_ffma(nir_shader *shader); bool nir_opt_remove_phis(nir_shader *shader); +bool nir_opt_undef(nir_shader *shader); + void nir_sweep(nir_shader *shader); #ifdef __cplusplus diff --git a/src/glsl/nir/nir_opt_undef.c b/src/glsl/nir/nir_opt_undef.c new file mode 100644 index 00000000000..4ab27a8c9d5 --- /dev/null +++ b/src/glsl/nir/nir_opt_undef.c @@ -0,0 +1,104 @@ +/* + * Copyright © 2015 Broadcom + * + * 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 "nir.h" + +/** @file nir_opt_undef.c + * + * Handles optimization of operations involving ssa_undef. For now, we just + * make sure that csels between undef and some other value just give the other + * value (on the assumption that the condition's going to be choosing the + * defined value). This reduces work after if flattening when each side of + * the if is defining a variable. + * + * Some day, we may find some use for making other operations consuming an + * undef arg output undef, but I don't know of any cases currently. + */ + +static bool +opt_undef_alu(nir_alu_instr *instr) +{ + if (instr->op != nir_op_bcsel && instr->op != nir_op_fcsel) + return false; + + assert(instr->dest.dest.is_ssa); + + for (int i = 1; i <= 2; i++) { + if (!instr->src[i].src.is_ssa) + continue; + + nir_instr *parent = instr->src[i].src.ssa->parent_instr; + if (parent->type != nir_instr_type_ssa_undef) + continue; + + /* We can't just use nir_alu_src_copy, because we need the def/use + * updated. + */ + nir_instr_rewrite_src(&instr->instr, &instr->src[0].src, + instr->src[i == 1 ? 2 : 1].src); + nir_alu_src_copy(&instr->src[0], &instr->src[i == 1 ? 2 : 1], + ralloc_parent(instr)); + + nir_src empty_src; + memset(&empty_src, 0, sizeof(empty_src)); + nir_instr_rewrite_src(&instr->instr, &instr->src[1].src, empty_src); + nir_instr_rewrite_src(&instr->instr, &instr->src[2].src, empty_src); + instr->op = nir_op_imov; + + return true; + } + + return false; +} + +static bool +opt_undef_block(nir_block *block, void *data) +{ + bool *progress = data; + + nir_foreach_instr_safe(block, instr) { + if (instr->type == nir_instr_type_alu) + if (opt_undef_alu(nir_instr_as_alu(instr))) + (*progress) = true; + } + + return true; +} + +bool +nir_opt_undef(nir_shader *shader) +{ + bool progress = false; + + nir_foreach_overload(shader, overload) { + if (overload->impl) { + nir_foreach_block(overload->impl, opt_undef_block, &progress); + if (progress) + nir_metadata_preserve(overload->impl, + nir_metadata_block_index | + nir_metadata_dominance); + } + } + + return progress; +} |