| /* |
| * Copyright © 2020 Advanced Micro Devices, Inc. |
| * |
| * 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. |
| */ |
| |
| /* These passes enable converting uniforms to literals when it's profitable, |
| * effectively inlining uniform values in the IR. The main benefit is register |
| * usage decrease leading to better SMT (hyperthreading). It's accomplished |
| * by targetting uniforms that determine whether a conditional branch is |
| * taken or a loop can be unrolled. |
| * |
| * Only uniforms used in these places are analyzed: |
| * 1. if condition |
| * 2. loop terminator |
| * 3. init and update value of induction variable used in loop terminator |
| * |
| * nir_find_inlinable_uniforms finds uniforms that can be inlined and stores |
| * that information in shader_info. |
| * |
| * nir_inline_uniforms inlines uniform values. |
| * |
| * (uniforms must be lowered to load_ubo before calling this) |
| */ |
| |
| #include "nir_builder.h" |
| #include "nir_loop_analyze.h" |
| |
| /* Maximum value in shader_info::inlinable_uniform_dw_offsets[] */ |
| #define MAX_OFFSET (UINT16_MAX * 4) |
| |
| #define MAX_NUM_BO 32 |
| |
| /** |
| * Collect uniforms used in a source |
| * |
| * Recursively collects all of the UBO loads with constant UBO index and |
| * constant offset (per the restictions of \c max_num_bo and \c |
| * max_offset). If any values are discovered that are non-constant, uniforms |
| * that don't meet the restrictions, or if more than \c |
| * MAX_INLINEABLE_UNIFORMS are discoverd for any one UBO, false is returned. |
| * |
| * When false is returned, the state of \c uni_offsets and \c num_offsets is |
| * undefined. |
| * |
| * \param max_num_bo Maximum number of uniform buffer objects |
| * \param max_offset Maximum offset within a UBO |
| * \param uni_offset Array of \c max_num_bo * \c MAX_INLINABLE_UNIFORMS values |
| * used to store offsets of discovered uniform loads. |
| * \param num_offsets Array of \c max_num_bo values used to store the number |
| * of uniforms collected from each UBO. |
| */ |
| bool |
| nir_collect_src_uniforms(const nir_src *src, int component, |
| uint32_t *uni_offsets, uint8_t *num_offsets, |
| unsigned max_num_bo, unsigned max_offset) |
| { |
| assert(max_num_bo > 0 && max_num_bo <= MAX_NUM_BO); |
| assert(component < src->ssa->num_components); |
| |
| nir_instr *instr = src->ssa->parent_instr; |
| |
| switch (instr->type) { |
| case nir_instr_type_alu: { |
| nir_alu_instr *alu = nir_instr_as_alu(instr); |
| |
| /* Vector ops only need to check the corresponding component. */ |
| if (alu->op == nir_op_mov) { |
| return nir_collect_src_uniforms(&alu->src[0].src, |
| alu->src[0].swizzle[component], |
| uni_offsets, num_offsets, |
| max_num_bo, max_offset); |
| } else if (nir_op_is_vec(alu->op)) { |
| nir_alu_src *alu_src = alu->src + component; |
| return nir_collect_src_uniforms(&alu_src->src, alu_src->swizzle[0], |
| uni_offsets, num_offsets, |
| max_num_bo, max_offset); |
| } |
| |
| /* Return true if all sources return true. */ |
| for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++) { |
| nir_alu_src *alu_src = alu->src + i; |
| int input_sizes = nir_op_infos[alu->op].input_sizes[i]; |
| |
| if (input_sizes == 0) { |
| /* For ops which has no input size, each component of dest is |
| * only determined by the same component of srcs. |
| */ |
| if (!nir_collect_src_uniforms(&alu_src->src, alu_src->swizzle[component], |
| uni_offsets, num_offsets, |
| max_num_bo, max_offset)) |
| return false; |
| } else { |
| /* For ops which has input size, all components of dest are |
| * determined by all components of srcs (except vec ops). |
| */ |
| for (unsigned j = 0; j < input_sizes; j++) { |
| if (!nir_collect_src_uniforms(&alu_src->src, alu_src->swizzle[j], |
| uni_offsets, num_offsets, |
| max_num_bo, max_offset)) |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| case nir_instr_type_intrinsic: { |
| nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); |
| /* Return true if the intrinsic loads from UBO 0 with a constant |
| * offset. |
| */ |
| if (intr->intrinsic == nir_intrinsic_load_ubo && |
| nir_src_is_const(intr->src[0]) && nir_src_num_components(intr->src[0]) == 1 && |
| nir_src_as_uint(intr->src[0]) < max_num_bo && |
| nir_src_is_const(intr->src[1]) && |
| nir_src_as_uint(intr->src[1]) <= max_offset && |
| /* TODO: Can't handle other bit sizes for now. */ |
| intr->def.bit_size == 32) { |
| /* num_offsets can be NULL if-and-only-if uni_offsets is NULL. */ |
| assert((num_offsets == NULL) == (uni_offsets == NULL)); |
| |
| /* If we're just checking that it's a uniform load, don't check (or |
| * add to) the table. |
| */ |
| if (uni_offsets == NULL) |
| return true; |
| |
| uint32_t offset = nir_src_as_uint(intr->src[1]) + component * 4; |
| assert(offset < MAX_OFFSET); |
| |
| const unsigned ubo = nir_src_as_uint(intr->src[0]); |
| |
| /* Already recorded by other one */ |
| for (int i = 0; i < num_offsets[ubo]; i++) { |
| if (uni_offsets[ubo * MAX_INLINABLE_UNIFORMS + i] == offset) |
| return true; |
| } |
| |
| /* Exceed uniform number limit */ |
| if (num_offsets[ubo] == MAX_INLINABLE_UNIFORMS) |
| return false; |
| |
| /* Record the uniform offset. */ |
| uni_offsets[ubo * MAX_INLINABLE_UNIFORMS + num_offsets[ubo]++] = offset; |
| return true; |
| } |
| return false; |
| } |
| |
| case nir_instr_type_load_const: |
| /* Always return true for constants. */ |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| static bool |
| is_induction_variable(const nir_src *src, int component, nir_loop_info *info, |
| uint32_t *uni_offsets, uint8_t *num_offsets, |
| unsigned max_num_bo, unsigned max_offset) |
| { |
| assert(component < src->ssa->num_components); |
| |
| /* Return true for induction variable (ie. i in for loop) */ |
| for (int i = 0; i < info->num_induction_vars; i++) { |
| nir_loop_induction_variable *var = info->induction_vars + i; |
| if (var->def == src->ssa) { |
| /* Induction variable should have constant initial value (ie. i = 0), |
| * constant update value (ie. i++) and constant end condition |
| * (ie. i < 10), so that we know the exact loop count for unrolling |
| * the loop. |
| * |
| * Add uniforms need to be inlined for this induction variable's |
| * initial and update value to be constant, for example: |
| * |
| * for (i = init; i < count; i += step) |
| * |
| * We collect uniform "init" and "step" here. |
| */ |
| if (var->init_src) { |
| if (!nir_collect_src_uniforms(var->init_src, component, |
| uni_offsets, num_offsets, |
| max_num_bo, max_offset)) |
| return false; |
| } |
| |
| if (var->update_src) { |
| nir_alu_src *alu_src = var->update_src; |
| if (!nir_collect_src_uniforms(&alu_src->src, |
| alu_src->swizzle[component], |
| uni_offsets, num_offsets, |
| max_num_bo, max_offset)) |
| return false; |
| } |
| |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| void |
| nir_add_inlinable_uniforms(const nir_src *cond, nir_loop_info *info, |
| uint32_t *uni_offsets, uint8_t *num_offsets, |
| unsigned max_num_bo, unsigned max_offset) |
| { |
| uint8_t new_num[MAX_NUM_BO]; |
| memcpy(new_num, num_offsets, sizeof(new_num)); |
| |
| /* If condition SSA is always scalar, so component is 0. */ |
| unsigned component = 0; |
| |
| /* Allow induction variable which means a loop terminator. */ |
| if (info) { |
| nir_scalar cond_scalar = { cond->ssa, 0 }; |
| |
| /* Limit terminator condition to loop unroll support case which is a simple |
| * comparison (ie. "i < count" is supported, but "i + 1 < count" is not). |
| */ |
| if (nir_is_supported_terminator_condition(cond_scalar)) { |
| if (nir_scalar_alu_op(cond_scalar) == nir_op_inot) |
| cond_scalar = nir_scalar_chase_alu_src(cond_scalar, 0); |
| |
| nir_alu_instr *alu = nir_instr_as_alu(cond_scalar.def->parent_instr); |
| |
| /* One side of comparison is induction variable, the other side is |
| * only uniform. |
| */ |
| for (int i = 0; i < 2; i++) { |
| if (is_induction_variable(&alu->src[i].src, alu->src[i].swizzle[0], |
| info, uni_offsets, new_num, |
| max_num_bo, max_offset)) { |
| cond = &alu->src[1 - i].src; |
| component = alu->src[1 - i].swizzle[0]; |
| break; |
| } |
| } |
| } |
| } |
| |
| /* Only update uniform number when all uniforms in the expression |
| * can be inlined. Partially inline uniforms can't lower if/loop. |
| * |
| * For example, uniform can be inlined for a shader is limited to 4, |
| * and we have already added 3 uniforms, then want to deal with |
| * |
| * if (uniform0 + uniform1 == 10) |
| * |
| * only uniform0 can be inlined due to we exceed the 4 limit. But |
| * unless both uniform0 and uniform1 are inlined, can we eliminate |
| * the if statement. |
| * |
| * This is even possible when we deal with loop if the induction |
| * variable init and update also contains uniform like |
| * |
| * for (i = uniform0; i < uniform1; i+= uniform2) |
| * |
| * unless uniform0, uniform1 and uniform2 can be inlined at once, |
| * can the loop be unrolled. |
| */ |
| if (nir_collect_src_uniforms(cond, component, uni_offsets, new_num, |
| max_num_bo, max_offset)) |
| memcpy(num_offsets, new_num, sizeof(new_num[0]) * max_num_bo); |
| } |
| |
| static void |
| process_node(nir_cf_node *node, nir_loop_info *info, |
| uint32_t *uni_offsets, uint8_t *num_offsets) |
| { |
| switch (node->type) { |
| case nir_cf_node_if: { |
| nir_if *if_node = nir_cf_node_as_if(node); |
| const nir_src *cond = &if_node->condition; |
| nir_add_inlinable_uniforms(cond, info, uni_offsets, num_offsets, |
| 1, MAX_OFFSET); |
| |
| /* Do not pass loop info down so only alow induction variable |
| * in loop terminator "if": |
| * |
| * for (i = 0; true; i++) |
| * if (i == count) |
| * if (i == num) |
| * <no break> |
| * break |
| * |
| * so "num" won't be inlined due to the "if" is not a |
| * terminator. |
| */ |
| info = NULL; |
| |
| foreach_list_typed(nir_cf_node, nested_node, node, &if_node->then_list) |
| process_node(nested_node, info, uni_offsets, num_offsets); |
| foreach_list_typed(nir_cf_node, nested_node, node, &if_node->else_list) |
| process_node(nested_node, info, uni_offsets, num_offsets); |
| break; |
| } |
| |
| case nir_cf_node_loop: { |
| nir_loop *loop = nir_cf_node_as_loop(node); |
| assert(!nir_loop_has_continue_construct(loop)); |
| |
| /* Replace loop info, no nested loop info currently: |
| * |
| * for (i = 0; i < count0; i++) |
| * for (j = 0; j < count1; j++) |
| * if (i == num) |
| * |
| * so "num" won't be inlined due to "i" is an induction |
| * variable of upper loop. |
| */ |
| info = loop->info; |
| |
| foreach_list_typed(nir_cf_node, nested_node, node, &loop->body) { |
| bool is_terminator = false; |
| list_for_each_entry(nir_loop_terminator, terminator, |
| &info->loop_terminator_list, |
| loop_terminator_link) { |
| if (nested_node == &terminator->nif->cf_node) { |
| is_terminator = true; |
| break; |
| } |
| } |
| |
| /* Allow induction variables for terminator "if" only: |
| * |
| * for (i = 0; i < count; i++) |
| * if (i == num) |
| * <no break> |
| * |
| * so "num" won't be inlined due to the "if" is not a |
| * terminator. |
| */ |
| nir_loop_info *use_info = is_terminator ? info : NULL; |
| process_node(nested_node, use_info, uni_offsets, num_offsets); |
| } |
| break; |
| } |
| |
| default: |
| break; |
| } |
| } |
| |
| void |
| nir_find_inlinable_uniforms(nir_shader *shader) |
| { |
| uint32_t uni_offsets[MAX_INLINABLE_UNIFORMS]; |
| uint8_t num_offsets[MAX_NUM_BO] = {0}; |
| |
| nir_foreach_function_impl(impl, shader) { |
| nir_metadata_require(impl, nir_metadata_loop_analysis, |
| nir_var_all, false); |
| |
| foreach_list_typed(nir_cf_node, node, node, &impl->body) |
| process_node(node, NULL, uni_offsets, num_offsets); |
| } |
| |
| for (int i = 0; i < num_offsets[0]; i++) |
| shader->info.inlinable_uniform_dw_offsets[i] = uni_offsets[i] / 4; |
| shader->info.num_inlinable_uniforms = num_offsets[0]; |
| } |
| |
| void |
| nir_inline_uniforms(nir_shader *shader, unsigned num_uniforms, |
| const uint32_t *uniform_values, |
| const uint16_t *uniform_dw_offsets) |
| { |
| if (!num_uniforms) |
| return; |
| |
| nir_foreach_function_impl(impl, shader) { |
| nir_builder b = nir_builder_create(impl); |
| nir_foreach_block(block, impl) { |
| nir_foreach_instr_safe(instr, block) { |
| if (instr->type != nir_instr_type_intrinsic) |
| continue; |
| |
| nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); |
| |
| /* Only replace UBO 0 with constant offsets. */ |
| if (intr->intrinsic == nir_intrinsic_load_ubo && |
| nir_src_is_const(intr->src[0]) && |
| nir_src_as_uint(intr->src[0]) == 0 && |
| nir_src_is_const(intr->src[1]) && |
| /* TODO: Can't handle other bit sizes for now. */ |
| intr->def.bit_size == 32) { |
| int num_components = intr->def.num_components; |
| uint32_t offset = nir_src_as_uint(intr->src[1]) / 4; |
| |
| if (num_components == 1) { |
| /* Just replace the uniform load to constant load. */ |
| for (unsigned i = 0; i < num_uniforms; i++) { |
| if (offset == uniform_dw_offsets[i]) { |
| b.cursor = nir_before_instr(&intr->instr); |
| nir_def *def = nir_imm_int(&b, uniform_values[i]); |
| nir_def_replace(&intr->def, def); |
| break; |
| } |
| } |
| } else { |
| /* Lower vector uniform load to scalar and replace each |
| * found component load with constant load. |
| */ |
| uint32_t max_offset = offset + num_components; |
| nir_def *components[NIR_MAX_VEC_COMPONENTS] = { 0 }; |
| bool found = false; |
| |
| b.cursor = nir_before_instr(&intr->instr); |
| |
| /* Find component to replace. */ |
| for (unsigned i = 0; i < num_uniforms; i++) { |
| uint32_t uni_offset = uniform_dw_offsets[i]; |
| if (uni_offset >= offset && uni_offset < max_offset) { |
| int index = uni_offset - offset; |
| components[index] = nir_imm_int(&b, uniform_values[i]); |
| found = true; |
| } |
| } |
| |
| if (!found) |
| continue; |
| |
| /* Create per-component uniform load. */ |
| for (unsigned i = 0; i < num_components; i++) { |
| if (!components[i]) { |
| uint32_t scalar_offset = (offset + i) * 4; |
| components[i] = nir_load_ubo(&b, 1, intr->def.bit_size, |
| intr->src[0].ssa, |
| nir_imm_int(&b, scalar_offset)); |
| nir_intrinsic_instr *load = |
| nir_instr_as_intrinsic(components[i]->parent_instr); |
| nir_intrinsic_set_align(load, NIR_ALIGN_MUL_MAX, scalar_offset); |
| nir_intrinsic_set_range_base(load, scalar_offset); |
| nir_intrinsic_set_range(load, 4); |
| } |
| } |
| |
| /* Replace the original uniform load. */ |
| nir_def_replace(&intr->def, |
| nir_vec(&b, components, num_components)); |
| } |
| } |
| } |
| |
| nir_metadata_preserve(impl, nir_metadata_control_flow); |
| } |
| } |
| } |
