From: Connor Abbott Date: Wed, 23 Jul 2014 18:19:50 +0000 (-0700) Subject: nir: add an SSA-based copy propagation pass X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8b7cb7674c735d83cd9a2b41e3d1f367353a20d4;p=mesa.git nir: add an SSA-based copy propagation pass --- diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources index 0aaea580816..556648b0768 100644 --- a/src/glsl/Makefile.sources +++ b/src/glsl/Makefile.sources @@ -25,6 +25,7 @@ NIR_FILES = \ $(GLSL_SRCDIR)/nir/nir_lower_variables_scalar.c \ $(GLSL_SRCDIR)/nir/nir_opcodes.c \ $(GLSL_SRCDIR)/nir/nir_opcodes.h \ + $(GLSL_SRCDIR)/nir/nir_opt_copy_propagate.c \ $(GLSL_SRCDIR)/nir/nir_opt_global_to_local.c \ $(GLSL_SRCDIR)/nir/nir_print.c \ $(GLSL_SRCDIR)/nir/nir_remove_dead_variables.c \ diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h index feaf21dd656..c764aafdf15 100644 --- a/src/glsl/nir/nir.h +++ b/src/glsl/nir/nir.h @@ -1293,6 +1293,9 @@ void nir_convert_to_ssa(nir_shader *shader); bool nir_opt_global_to_local(nir_shader *shader); +bool nir_copy_prop_impl(nir_function_impl *impl); +bool nir_copy_prop(nir_shader *shader); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/src/glsl/nir/nir_opt_copy_propagate.c b/src/glsl/nir/nir_opt_copy_propagate.c new file mode 100644 index 00000000000..a2be047a658 --- /dev/null +++ b/src/glsl/nir/nir_opt_copy_propagate.c @@ -0,0 +1,313 @@ +/* + * Copyright © 2014 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. + * + * Authors: + * Connor Abbott (cwabbott0@gmail.com) + * + */ + +#include "nir.h" +#include
+ +/** + * SSA-based copy propagation + */ + +static bool is_move(nir_alu_instr *instr) +{ + if (instr->op != nir_op_fmov && + instr->op != nir_op_imov) + return false; + + if (instr->dest.saturate) + return false; + + /* we handle modifiers in a separate pass */ + + if (instr->src[0].abs || instr->src[0].negate) + return false; + + if (!instr->src[0].src.is_ssa) + return false; + + return true; + +} + +static bool +is_swizzleless_move(nir_alu_instr *instr) +{ + if (!is_move(instr)) + return false; + + for (unsigned i = 0; i < 4; i++) { + if (!((instr->dest.write_mask >> i) & 1)) + break; + if (instr->src[0].swizzle[i] != i) + return false; + } + + return true; +} + +static bool is_vec(nir_alu_instr *instr) +{ + for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) + if (!instr->src[i].src.is_ssa) + return false; + + return instr->op == nir_op_vec2 || + instr->op == nir_op_vec3 || + instr->op == nir_op_vec4; +} + +typedef struct { + nir_ssa_def *def; + bool found; +} search_def_state; + +static bool +search_def(nir_src *src, void *_state) +{ + search_def_state *state = (search_def_state *) _state; + + if (src->is_ssa && src->ssa == state->def) + state->found = true; + + return true; +} + +static void +rewrite_src_instr(nir_src *src, nir_ssa_def *new_def, nir_instr *parent_instr) +{ + nir_ssa_def *old_def = src->ssa; + + src->ssa = new_def; + + /* + * The instruction could still use the old definition in one of its other + * sources, so only remove the instruction from the uses if there are no + * more uses left. + */ + + search_def_state search_state; + search_state.def = old_def; + search_state.found = false; + nir_foreach_src(parent_instr, search_def, &search_state); + if (!search_state.found) { + struct set_entry *entry = + _mesa_set_search(old_def->uses, _mesa_hash_pointer(parent_instr), + parent_instr); + assert(entry); + _mesa_set_remove(old_def->uses, entry); + } + + _mesa_set_add(new_def->uses, _mesa_hash_pointer(parent_instr), + parent_instr); +} + +static void +rewrite_src_if(nir_if *if_stmt, nir_ssa_def *new_def) +{ + nir_ssa_def *old_def = if_stmt->condition.ssa; + + if_stmt->condition.ssa = new_def; + + struct set_entry *entry = + _mesa_set_search(old_def->if_uses, _mesa_hash_pointer(if_stmt), if_stmt); + assert(entry); + _mesa_set_remove(old_def->if_uses, entry); + + _mesa_set_add(new_def->if_uses, _mesa_hash_pointer(if_stmt), if_stmt); +} + +static bool +copy_prop_src(nir_src *src, nir_instr *parent_instr, nir_if *parent_if) +{ + if (!src->is_ssa) { + if (src->reg.indirect) + return copy_prop_src(src, parent_instr, parent_if); + return false; + } + + nir_instr *src_instr = src->ssa->parent_instr; + if (src_instr->type != nir_instr_type_alu) + return false; + + nir_alu_instr *alu_instr = nir_instr_as_alu(src_instr); + if (!is_swizzleless_move(alu_instr)) + return false; + + if (parent_instr) + rewrite_src_instr(src, alu_instr->src[0].src.ssa, parent_instr); + else + rewrite_src_if(parent_if, alu_instr->src[0].src.ssa); + + return true; +} + +static bool +copy_prop_alu_src(nir_alu_instr *parent_alu_instr, unsigned index) +{ + nir_alu_src *src = &parent_alu_instr->src[index]; + if (!src->src.is_ssa) { + if (src->src.reg.indirect) + return copy_prop_src(src->src.reg.indirect, &parent_alu_instr->instr, + NULL); + return false; + } + + nir_instr *src_instr = src->src.ssa->parent_instr; + if (src_instr->type != nir_instr_type_alu) + return false; + + nir_alu_instr *alu_instr = nir_instr_as_alu(src_instr); + if (!is_move(alu_instr) && !is_vec(alu_instr)) + return false; + + nir_ssa_def *def; + unsigned new_swizzle[4] = {0, 0, 0, 0}; + + if (alu_instr->op == nir_op_fmov || + alu_instr->op == nir_op_imov) { + for (unsigned i = 0; i < 4; i++) + new_swizzle[i] = alu_instr->src[0].swizzle[src->swizzle[i]]; + def = alu_instr->src[0].src.ssa; + } else { + def = NULL; + + for (unsigned i = 0; i < 4; i++) { + if (!nir_alu_instr_channel_used(parent_alu_instr, index, i)) + continue; + + nir_ssa_def *new_def = alu_instr->src[src->swizzle[i]].src.ssa; + if (def == NULL) + def = new_def; + else { + if (def != new_def) + return false; + } + new_swizzle[i] = alu_instr->src[src->swizzle[i]].swizzle[0]; + } + } + + for (unsigned i = 0; i < 4; i++) + src->swizzle[i] = new_swizzle[i]; + + rewrite_src_instr(&src->src, def, &parent_alu_instr->instr); + + return true; +} + +typedef struct { + nir_instr *parent_instr; + bool progress; +} copy_prop_state; + +static bool +copy_prop_src_cb(nir_src *src, void *_state) +{ + copy_prop_state *state = (copy_prop_state *) _state; + while (copy_prop_src(src, state->parent_instr, NULL)) + state->progress = true; + + return true; +} + +static bool +copy_prop_instr(nir_instr *instr) +{ + if (instr->type == nir_instr_type_alu) { + nir_alu_instr *alu_instr = nir_instr_as_alu(instr); + bool progress = false; + + for (unsigned i = 0; i < nir_op_infos[alu_instr->op].num_inputs; i++) + while (copy_prop_alu_src(alu_instr, i)) + progress = true; + + if (alu_instr->has_predicate) + while (copy_prop_src(&alu_instr->predicate, instr, NULL)) + progress = true; + + if (!alu_instr->dest.dest.is_ssa && alu_instr->dest.dest.reg.indirect) + while (copy_prop_src(alu_instr->dest.dest.reg.indirect, instr, NULL)) + progress = true; + + return progress; + } + + copy_prop_state state; + state.parent_instr = instr; + state.progress = false; + nir_foreach_src(instr, copy_prop_src_cb, &state); + + return state.progress; +} + +static bool +copy_prop_if(nir_if *if_stmt) +{ + return copy_prop_src(&if_stmt->condition, NULL, if_stmt); +} + +static bool +copy_prop_block(nir_block *block, void *_state) +{ + bool *progress = (bool *) _state; + + nir_foreach_instr(block, instr) { + if (copy_prop_instr(instr)) + *progress = true; + } + + if (block->cf_node.node.next != NULL && /* check that we aren't the end node */ + !nir_cf_node_is_last(&block->cf_node) && + nir_cf_node_next(&block->cf_node)->type == nir_cf_node_if) { + nir_if *if_stmt = nir_cf_node_as_if(nir_cf_node_next(&block->cf_node)); + if (copy_prop_if(if_stmt)) + *progress = true; + } + + return true; +} + +bool +nir_copy_prop_impl(nir_function_impl *impl) +{ + bool progress = false; + + nir_foreach_block(impl, copy_prop_block, &progress); + return progress; +} + +bool +nir_copy_prop(nir_shader *shader) +{ + bool progress = false; + + nir_foreach_overload(shader, overload) { + if (overload->impl && nir_copy_prop_impl(overload->impl)) + progress = true; + } + + return progress; +}