| /* |
| * 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: |
| * Jason Ekstrand (jason@jlekstrand.net) |
| * |
| */ |
| |
| #include "nir.h" |
| #include "nir_builder.h" |
| #include "nir_constant_expressions.h" |
| #include "nir_deref.h" |
| #include <math.h> |
| |
| /* |
| * Implements SSA-based constant folding. |
| */ |
| |
| struct constant_fold_state { |
| bool has_load_constant; |
| bool has_indirect_load_const; |
| }; |
| |
| static bool |
| try_fold_alu(nir_builder *b, nir_alu_instr *instr) |
| { |
| nir_const_value src[NIR_MAX_VEC_COMPONENTS][NIR_MAX_VEC_COMPONENTS]; |
| |
| if (!instr->dest.dest.is_ssa) |
| return false; |
| |
| /* In the case that any outputs/inputs have unsized types, then we need to |
| * guess the bit-size. In this case, the validator ensures that all |
| * bit-sizes match so we can just take the bit-size from first |
| * output/input with an unsized type. If all the outputs/inputs are sized |
| * then we don't need to guess the bit-size at all because the code we |
| * generate for constant opcodes in this case already knows the sizes of |
| * the types involved and does not need the provided bit-size for anything |
| * (although it still requires to receive a valid bit-size). |
| */ |
| unsigned bit_size = 0; |
| if (!nir_alu_type_get_type_size(nir_op_infos[instr->op].output_type)) |
| bit_size = instr->dest.dest.ssa.bit_size; |
| |
| for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) { |
| if (!instr->src[i].src.is_ssa) |
| return false; |
| |
| if (bit_size == 0 && |
| !nir_alu_type_get_type_size(nir_op_infos[instr->op].input_types[i])) |
| bit_size = instr->src[i].src.ssa->bit_size; |
| |
| nir_instr *src_instr = instr->src[i].src.ssa->parent_instr; |
| |
| if (src_instr->type != nir_instr_type_load_const) |
| return false; |
| nir_load_const_instr* load_const = nir_instr_as_load_const(src_instr); |
| |
| for (unsigned j = 0; j < nir_ssa_alu_instr_src_components(instr, i); |
| j++) { |
| src[i][j] = load_const->value[instr->src[i].swizzle[j]]; |
| } |
| |
| /* We shouldn't have any source modifiers in the optimization loop. */ |
| assert(!instr->src[i].abs && !instr->src[i].negate); |
| } |
| |
| if (bit_size == 0) |
| bit_size = 32; |
| |
| /* We shouldn't have any saturate modifiers in the optimization loop. */ |
| assert(!instr->dest.saturate); |
| |
| nir_const_value dest[NIR_MAX_VEC_COMPONENTS]; |
| nir_const_value *srcs[NIR_MAX_VEC_COMPONENTS]; |
| memset(dest, 0, sizeof(dest)); |
| for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; ++i) |
| srcs[i] = src[i]; |
| nir_eval_const_opcode(instr->op, dest, instr->dest.dest.ssa.num_components, |
| bit_size, srcs, |
| b->shader->info.float_controls_execution_mode); |
| |
| b->cursor = nir_before_instr(&instr->instr); |
| nir_ssa_def *imm = nir_build_imm(b, instr->dest.dest.ssa.num_components, |
| instr->dest.dest.ssa.bit_size, |
| dest); |
| nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(imm)); |
| nir_instr_remove(&instr->instr); |
| |
| ralloc_free(instr); |
| |
| return true; |
| } |
| |
| static nir_const_value * |
| const_value_for_deref(nir_deref_instr *deref) |
| { |
| if (deref->mode != nir_var_mem_constant) |
| return NULL; |
| |
| nir_deref_path path; |
| nir_deref_path_init(&path, deref, NULL); |
| if (path.path[0]->deref_type != nir_deref_type_var) |
| goto fail; |
| |
| nir_variable *var = path.path[0]->var; |
| assert(var->data.mode == nir_var_mem_constant); |
| if (var->constant_initializer == NULL) |
| goto fail; |
| |
| nir_constant *c = var->constant_initializer; |
| nir_const_value *v = NULL; /* Vector value for array-deref-of-vec */ |
| |
| for (unsigned i = 1; path.path[i] != NULL; i++) { |
| nir_deref_instr *p = path.path[i]; |
| switch (p->deref_type) { |
| case nir_deref_type_var: |
| unreachable("Deref paths can only start with a var deref"); |
| |
| case nir_deref_type_array: { |
| assert(v == NULL); |
| if (!nir_src_is_const(p->arr.index)) |
| goto fail; |
| |
| uint64_t idx = nir_src_as_uint(p->arr.index); |
| if (c->num_elements > 0) { |
| assert(glsl_type_is_array(path.path[i-1]->type)); |
| if (idx >= c->num_elements) |
| goto fail; |
| c = c->elements[idx]; |
| } else { |
| assert(glsl_type_is_vector(path.path[i-1]->type)); |
| assert(glsl_type_is_scalar(p->type)); |
| if (idx >= NIR_MAX_VEC_COMPONENTS) |
| goto fail; |
| v = &c->values[idx]; |
| } |
| break; |
| } |
| |
| case nir_deref_type_struct: |
| assert(glsl_type_is_struct(path.path[i-1]->type)); |
| assert(v == NULL && c->num_elements > 0); |
| if (p->strct.index >= c->num_elements) |
| goto fail; |
| c = c->elements[p->strct.index]; |
| break; |
| |
| default: |
| goto fail; |
| } |
| } |
| |
| /* We have to have ended at a vector */ |
| assert(c->num_elements == 0); |
| return v ? v : c->values; |
| |
| fail: |
| nir_deref_path_finish(&path); |
| return NULL; |
| } |
| |
| static bool |
| try_fold_intrinsic(nir_builder *b, nir_intrinsic_instr *instr, |
| struct constant_fold_state *state) |
| { |
| bool progress = false; |
| |
| if ((instr->intrinsic == nir_intrinsic_demote_if || |
| instr->intrinsic == nir_intrinsic_discard_if) && |
| nir_src_is_const(instr->src[0])) { |
| if (nir_src_as_bool(instr->src[0])) { |
| b->cursor = nir_before_instr(&instr->instr); |
| nir_intrinsic_op op = instr->intrinsic == nir_intrinsic_discard_if ? |
| nir_intrinsic_discard : |
| nir_intrinsic_demote; |
| nir_intrinsic_instr *new_instr = |
| nir_intrinsic_instr_create(b->shader, op); |
| nir_builder_instr_insert(b, &new_instr->instr); |
| } |
| nir_instr_remove(&instr->instr); |
| progress = true; |
| } else if (instr->intrinsic == nir_intrinsic_load_deref) { |
| nir_deref_instr *deref = nir_src_as_deref(instr->src[0]); |
| nir_const_value *v = const_value_for_deref(deref); |
| if (v) { |
| b->cursor = nir_before_instr(&instr->instr); |
| nir_ssa_def *val = nir_build_imm(b, instr->dest.ssa.num_components, |
| instr->dest.ssa.bit_size, v); |
| nir_ssa_def_rewrite_uses(&instr->dest.ssa, nir_src_for_ssa(val)); |
| nir_instr_remove(&instr->instr); |
| progress = true; |
| } |
| } else if (instr->intrinsic == nir_intrinsic_load_constant) { |
| state->has_load_constant = true; |
| |
| if (!nir_src_is_const(instr->src[0])) { |
| state->has_indirect_load_const = true; |
| return progress; |
| } |
| |
| unsigned offset = nir_src_as_uint(instr->src[0]); |
| unsigned base = nir_intrinsic_base(instr); |
| unsigned range = nir_intrinsic_range(instr); |
| assert(base + range <= b->shader->constant_data_size); |
| |
| b->cursor = nir_before_instr(&instr->instr); |
| nir_ssa_def *val; |
| if (offset >= range) { |
| val = nir_ssa_undef(b, instr->dest.ssa.num_components, |
| instr->dest.ssa.bit_size); |
| } else { |
| nir_const_value imm[NIR_MAX_VEC_COMPONENTS]; |
| memset(imm, 0, sizeof(imm)); |
| uint8_t *data = (uint8_t*)b->shader->constant_data + base; |
| for (unsigned i = 0; i < instr->num_components; i++) { |
| unsigned bytes = instr->dest.ssa.bit_size / 8; |
| bytes = MIN2(bytes, range - offset); |
| |
| memcpy(&imm[i].u64, data + offset, bytes); |
| offset += bytes; |
| } |
| val = nir_build_imm(b, instr->dest.ssa.num_components, |
| instr->dest.ssa.bit_size, imm); |
| } |
| nir_ssa_def_rewrite_uses(&instr->dest.ssa, nir_src_for_ssa(val)); |
| nir_instr_remove(&instr->instr); |
| progress = true; |
| } |
| |
| return progress; |
| } |
| |
| static bool |
| try_fold_instr(nir_builder *b, nir_instr *instr, void *_state) |
| { |
| switch (instr->type) { |
| case nir_instr_type_alu: |
| return try_fold_alu(b, nir_instr_as_alu(instr)); |
| case nir_instr_type_intrinsic: |
| return try_fold_intrinsic(b, nir_instr_as_intrinsic(instr), _state); |
| default: |
| /* Don't know how to constant fold */ |
| return false; |
| } |
| } |
| |
| bool |
| nir_opt_constant_folding(nir_shader *shader) |
| { |
| struct constant_fold_state state; |
| state.has_load_constant = false; |
| state.has_indirect_load_const = false; |
| |
| bool progress = nir_shader_instructions_pass(shader, try_fold_instr, |
| nir_metadata_block_index | |
| nir_metadata_dominance, |
| &state); |
| |
| /* This doesn't free the constant data if there are no constant loads because |
| * the data might still be used but the loads have been lowered to load_ubo |
| */ |
| if (state.has_load_constant && !state.has_indirect_load_const && |
| shader->constant_data_size) { |
| ralloc_free(shader->constant_data); |
| shader->constant_data = NULL; |
| shader->constant_data_size = 0; |
| } |
| |
| return progress; |
| } |