| /* |
| * Copyright © 2011 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. |
| */ |
| |
| extern "C" { |
| #include "main/macros.h" |
| #include "program/register_allocate.h" |
| } /* extern "C" */ |
| |
| #include "brw_vec4.h" |
| #include "brw_vs.h" |
| |
| using namespace brw; |
| |
| namespace brw { |
| |
| static void |
| assign(unsigned int *reg_hw_locations, reg *reg) |
| { |
| if (reg->file == GRF) { |
| reg->reg = reg_hw_locations[reg->reg]; |
| } |
| } |
| |
| bool |
| vec4_visitor::reg_allocate_trivial() |
| { |
| unsigned int hw_reg_mapping[this->virtual_grf_count]; |
| bool virtual_grf_used[this->virtual_grf_count]; |
| int i; |
| int next; |
| |
| /* Calculate which virtual GRFs are actually in use after whatever |
| * optimization passes have occurred. |
| */ |
| for (int i = 0; i < this->virtual_grf_count; i++) { |
| virtual_grf_used[i] = false; |
| } |
| |
| foreach_in_list(vec4_instruction, inst, &instructions) { |
| if (inst->dst.file == GRF) |
| virtual_grf_used[inst->dst.reg] = true; |
| |
| for (int i = 0; i < 3; i++) { |
| if (inst->src[i].file == GRF) |
| virtual_grf_used[inst->src[i].reg] = true; |
| } |
| } |
| |
| hw_reg_mapping[0] = this->first_non_payload_grf; |
| next = hw_reg_mapping[0] + this->virtual_grf_sizes[0]; |
| for (i = 1; i < this->virtual_grf_count; i++) { |
| if (virtual_grf_used[i]) { |
| hw_reg_mapping[i] = next; |
| next += this->virtual_grf_sizes[i]; |
| } |
| } |
| prog_data->total_grf = next; |
| |
| foreach_in_list(vec4_instruction, inst, &instructions) { |
| assign(hw_reg_mapping, &inst->dst); |
| assign(hw_reg_mapping, &inst->src[0]); |
| assign(hw_reg_mapping, &inst->src[1]); |
| assign(hw_reg_mapping, &inst->src[2]); |
| } |
| |
| if (prog_data->total_grf > max_grf) { |
| fail("Ran out of regs on trivial allocator (%d/%d)\n", |
| prog_data->total_grf, max_grf); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| extern "C" void |
| brw_vec4_alloc_reg_set(struct intel_screen *screen) |
| { |
| int base_reg_count = |
| screen->devinfo->gen >= 7 ? GEN7_MRF_HACK_START : BRW_MAX_GRF; |
| |
| /* After running split_virtual_grfs(), almost all VGRFs will be of size 1. |
| * SEND-from-GRF sources cannot be split, so we also need classes for each |
| * potential message length. |
| */ |
| const int class_count = 2; |
| const int class_sizes[class_count] = {1, 2}; |
| |
| /* Compute the total number of registers across all classes. */ |
| int ra_reg_count = 0; |
| for (int i = 0; i < class_count; i++) { |
| ra_reg_count += base_reg_count - (class_sizes[i] - 1); |
| } |
| |
| ralloc_free(screen->vec4_reg_set.ra_reg_to_grf); |
| screen->vec4_reg_set.ra_reg_to_grf = ralloc_array(screen, uint8_t, ra_reg_count); |
| ralloc_free(screen->vec4_reg_set.regs); |
| screen->vec4_reg_set.regs = ra_alloc_reg_set(screen, ra_reg_count); |
| if (screen->devinfo->gen >= 6) |
| ra_set_allocate_round_robin(screen->vec4_reg_set.regs); |
| ralloc_free(screen->vec4_reg_set.classes); |
| screen->vec4_reg_set.classes = ralloc_array(screen, int, class_count); |
| |
| /* Now, add the registers to their classes, and add the conflicts |
| * between them and the base GRF registers (and also each other). |
| */ |
| int reg = 0; |
| for (int i = 0; i < class_count; i++) { |
| int class_reg_count = base_reg_count - (class_sizes[i] - 1); |
| screen->vec4_reg_set.classes[i] = ra_alloc_reg_class(screen->vec4_reg_set.regs); |
| |
| for (int j = 0; j < class_reg_count; j++) { |
| ra_class_add_reg(screen->vec4_reg_set.regs, screen->vec4_reg_set.classes[i], reg); |
| |
| screen->vec4_reg_set.ra_reg_to_grf[reg] = j; |
| |
| for (int base_reg = j; |
| base_reg < j + class_sizes[i]; |
| base_reg++) { |
| ra_add_transitive_reg_conflict(screen->vec4_reg_set.regs, base_reg, reg); |
| } |
| |
| reg++; |
| } |
| } |
| assert(reg == ra_reg_count); |
| |
| ra_set_finalize(screen->vec4_reg_set.regs, NULL); |
| } |
| |
| void |
| vec4_visitor::setup_payload_interference(struct ra_graph *g, |
| int first_payload_node, |
| int reg_node_count) |
| { |
| int payload_node_count = this->first_non_payload_grf; |
| |
| for (int i = 0; i < payload_node_count; i++) { |
| /* Mark each payload reg node as being allocated to its physical register. |
| * |
| * The alternative would be to have per-physical register classes, which |
| * would just be silly. |
| */ |
| ra_set_node_reg(g, first_payload_node + i, i); |
| |
| /* For now, just mark each payload node as interfering with every other |
| * node to be allocated. |
| */ |
| for (int j = 0; j < reg_node_count; j++) { |
| ra_add_node_interference(g, first_payload_node + i, j); |
| } |
| } |
| } |
| |
| bool |
| vec4_visitor::reg_allocate() |
| { |
| struct intel_screen *screen = brw->intelScreen; |
| unsigned int hw_reg_mapping[virtual_grf_count]; |
| int payload_reg_count = this->first_non_payload_grf; |
| |
| /* Using the trivial allocator can be useful in debugging undefined |
| * register access as a result of broken optimization passes. |
| */ |
| if (0) |
| return reg_allocate_trivial(); |
| |
| calculate_live_intervals(); |
| |
| int node_count = virtual_grf_count; |
| int first_payload_node = node_count; |
| node_count += payload_reg_count; |
| struct ra_graph *g = |
| ra_alloc_interference_graph(screen->vec4_reg_set.regs, node_count); |
| |
| for (int i = 0; i < virtual_grf_count; i++) { |
| int size = this->virtual_grf_sizes[i]; |
| assert(size >= 1 && size <= 2 && |
| "Register allocation relies on split_virtual_grfs()."); |
| ra_set_node_class(g, i, screen->vec4_reg_set.classes[size - 1]); |
| |
| for (int j = 0; j < i; j++) { |
| if (virtual_grf_interferes(i, j)) { |
| ra_add_node_interference(g, i, j); |
| } |
| } |
| } |
| |
| setup_payload_interference(g, first_payload_node, node_count); |
| |
| if (!ra_allocate_no_spills(g)) { |
| /* Failed to allocate registers. Spill a reg, and the caller will |
| * loop back into here to try again. |
| */ |
| int reg = choose_spill_reg(g); |
| if (this->no_spills) { |
| fail("Failure to register allocate. Reduce number of live " |
| "values to avoid this."); |
| } else if (reg == -1) { |
| fail("no register to spill\n"); |
| } else { |
| spill_reg(reg); |
| } |
| ralloc_free(g); |
| return false; |
| } |
| |
| /* Get the chosen virtual registers for each node, and map virtual |
| * regs in the register classes back down to real hardware reg |
| * numbers. |
| */ |
| prog_data->total_grf = payload_reg_count; |
| for (int i = 0; i < virtual_grf_count; i++) { |
| int reg = ra_get_node_reg(g, i); |
| |
| hw_reg_mapping[i] = screen->vec4_reg_set.ra_reg_to_grf[reg]; |
| prog_data->total_grf = MAX2(prog_data->total_grf, |
| hw_reg_mapping[i] + virtual_grf_sizes[i]); |
| } |
| |
| foreach_in_list(vec4_instruction, inst, &instructions) { |
| assign(hw_reg_mapping, &inst->dst); |
| assign(hw_reg_mapping, &inst->src[0]); |
| assign(hw_reg_mapping, &inst->src[1]); |
| assign(hw_reg_mapping, &inst->src[2]); |
| } |
| |
| ralloc_free(g); |
| |
| return true; |
| } |
| |
| void |
| vec4_visitor::evaluate_spill_costs(float *spill_costs, bool *no_spill) |
| { |
| float loop_scale = 1.0; |
| |
| for (int i = 0; i < this->virtual_grf_count; i++) { |
| spill_costs[i] = 0.0; |
| no_spill[i] = virtual_grf_sizes[i] != 1; |
| } |
| |
| /* Calculate costs for spilling nodes. Call it a cost of 1 per |
| * spill/unspill we'll have to do, and guess that the insides of |
| * loops run 10 times. |
| */ |
| foreach_in_list(vec4_instruction, inst, &instructions) { |
| for (unsigned int i = 0; i < 3; i++) { |
| if (inst->src[i].file == GRF) { |
| spill_costs[inst->src[i].reg] += loop_scale; |
| if (inst->src[i].reladdr) |
| no_spill[inst->src[i].reg] = true; |
| } |
| } |
| |
| if (inst->dst.file == GRF) { |
| spill_costs[inst->dst.reg] += loop_scale; |
| if (inst->dst.reladdr) |
| no_spill[inst->dst.reg] = true; |
| } |
| |
| switch (inst->opcode) { |
| |
| case BRW_OPCODE_DO: |
| loop_scale *= 10; |
| break; |
| |
| case BRW_OPCODE_WHILE: |
| loop_scale /= 10; |
| break; |
| |
| case SHADER_OPCODE_GEN4_SCRATCH_READ: |
| case SHADER_OPCODE_GEN4_SCRATCH_WRITE: |
| for (int i = 0; i < 3; i++) { |
| if (inst->src[i].file == GRF) |
| no_spill[inst->src[i].reg] = true; |
| } |
| if (inst->dst.file == GRF) |
| no_spill[inst->dst.reg] = true; |
| break; |
| |
| default: |
| break; |
| } |
| } |
| } |
| |
| int |
| vec4_visitor::choose_spill_reg(struct ra_graph *g) |
| { |
| float spill_costs[this->virtual_grf_count]; |
| bool no_spill[this->virtual_grf_count]; |
| |
| evaluate_spill_costs(spill_costs, no_spill); |
| |
| for (int i = 0; i < this->virtual_grf_count; i++) { |
| if (!no_spill[i]) |
| ra_set_node_spill_cost(g, i, spill_costs[i]); |
| } |
| |
| return ra_get_best_spill_node(g); |
| } |
| |
| void |
| vec4_visitor::spill_reg(int spill_reg_nr) |
| { |
| assert(virtual_grf_sizes[spill_reg_nr] == 1); |
| unsigned int spill_offset = c->last_scratch++; |
| |
| /* Generate spill/unspill instructions for the objects being spilled. */ |
| foreach_in_list(vec4_instruction, inst, &instructions) { |
| for (unsigned int i = 0; i < 3; i++) { |
| if (inst->src[i].file == GRF && inst->src[i].reg == spill_reg_nr) { |
| src_reg spill_reg = inst->src[i]; |
| inst->src[i].reg = virtual_grf_alloc(1); |
| dst_reg temp = dst_reg(inst->src[i]); |
| |
| /* Only read the necessary channels, to avoid overwriting the rest |
| * with data that may not have been written to scratch. |
| */ |
| temp.writemask = 0; |
| for (int c = 0; c < 4; c++) |
| temp.writemask |= (1 << BRW_GET_SWZ(inst->src[i].swizzle, c)); |
| assert(temp.writemask != 0); |
| |
| emit_scratch_read(inst, temp, spill_reg, spill_offset); |
| } |
| } |
| |
| if (inst->dst.file == GRF && inst->dst.reg == spill_reg_nr) { |
| emit_scratch_write(inst, spill_offset); |
| } |
| } |
| |
| invalidate_live_intervals(); |
| } |
| |
| } /* namespace brw */ |