| /* |
| * Copyright © 2012 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. |
| */ |
| |
| /** @file brw_fs_copy_propagation.cpp |
| * |
| * Support for global copy propagation in two passes: A local pass that does |
| * intra-block copy (and constant) propagation, and a global pass that uses |
| * dataflow analysis on the copies available at the end of each block to re-do |
| * local copy propagation with more copies available. |
| * |
| * See Muchnick's Advanced Compiler Design and Implementation, section |
| * 12.5 (p356). |
| */ |
| |
| #define ACP_HASH_SIZE 64 |
| |
| #include "util/bitset.h" |
| #include "util/u_math.h" |
| #include "brw_fs.h" |
| #include "brw_fs_live_variables.h" |
| #include "brw_cfg.h" |
| #include "brw_eu.h" |
| |
| using namespace brw; |
| |
| namespace { /* avoid conflict with opt_copy_propagation_elements */ |
| struct acp_entry : public exec_node { |
| fs_reg dst; |
| fs_reg src; |
| unsigned global_idx; |
| unsigned size_written; |
| unsigned size_read; |
| enum opcode opcode; |
| bool saturate; |
| }; |
| |
| struct block_data { |
| /** |
| * Which entries in the fs_copy_prop_dataflow acp table are live at the |
| * start of this block. This is the useful output of the analysis, since |
| * it lets us plug those into the local copy propagation on the second |
| * pass. |
| */ |
| BITSET_WORD *livein; |
| |
| /** |
| * Which entries in the fs_copy_prop_dataflow acp table are live at the end |
| * of this block. This is done in initial setup from the per-block acps |
| * returned by the first local copy prop pass. |
| */ |
| BITSET_WORD *liveout; |
| |
| /** |
| * Which entries in the fs_copy_prop_dataflow acp table are generated by |
| * instructions in this block which reach the end of the block without |
| * being killed. |
| */ |
| BITSET_WORD *copy; |
| |
| /** |
| * Which entries in the fs_copy_prop_dataflow acp table are killed over the |
| * course of this block. |
| */ |
| BITSET_WORD *kill; |
| |
| /** |
| * Which entries in the fs_copy_prop_dataflow acp table are guaranteed to |
| * have a fully uninitialized destination at the end of this block. |
| */ |
| BITSET_WORD *undef; |
| }; |
| |
| class fs_copy_prop_dataflow |
| { |
| public: |
| fs_copy_prop_dataflow(void *mem_ctx, cfg_t *cfg, |
| const fs_live_variables &live, |
| exec_list *out_acp[ACP_HASH_SIZE]); |
| |
| void setup_initial_values(); |
| void run(); |
| |
| void dump_block_data() const UNUSED; |
| |
| void *mem_ctx; |
| cfg_t *cfg; |
| const fs_live_variables &live; |
| |
| acp_entry **acp; |
| int num_acp; |
| int bitset_words; |
| |
| struct block_data *bd; |
| }; |
| } /* anonymous namespace */ |
| |
| fs_copy_prop_dataflow::fs_copy_prop_dataflow(void *mem_ctx, cfg_t *cfg, |
| const fs_live_variables &live, |
| exec_list *out_acp[ACP_HASH_SIZE]) |
| : mem_ctx(mem_ctx), cfg(cfg), live(live) |
| { |
| bd = rzalloc_array(mem_ctx, struct block_data, cfg->num_blocks); |
| |
| num_acp = 0; |
| foreach_block (block, cfg) { |
| for (int i = 0; i < ACP_HASH_SIZE; i++) { |
| num_acp += out_acp[block->num][i].length(); |
| } |
| } |
| |
| acp = rzalloc_array(mem_ctx, struct acp_entry *, num_acp); |
| |
| bitset_words = BITSET_WORDS(num_acp); |
| |
| int next_acp = 0; |
| foreach_block (block, cfg) { |
| bd[block->num].livein = rzalloc_array(bd, BITSET_WORD, bitset_words); |
| bd[block->num].liveout = rzalloc_array(bd, BITSET_WORD, bitset_words); |
| bd[block->num].copy = rzalloc_array(bd, BITSET_WORD, bitset_words); |
| bd[block->num].kill = rzalloc_array(bd, BITSET_WORD, bitset_words); |
| bd[block->num].undef = rzalloc_array(bd, BITSET_WORD, bitset_words); |
| |
| for (int i = 0; i < ACP_HASH_SIZE; i++) { |
| foreach_in_list(acp_entry, entry, &out_acp[block->num][i]) { |
| acp[next_acp] = entry; |
| |
| entry->global_idx = next_acp; |
| |
| /* opt_copy_propagation_local populates out_acp with copies created |
| * in a block which are still live at the end of the block. This |
| * is exactly what we want in the COPY set. |
| */ |
| BITSET_SET(bd[block->num].copy, next_acp); |
| |
| next_acp++; |
| } |
| } |
| } |
| |
| assert(next_acp == num_acp); |
| |
| setup_initial_values(); |
| run(); |
| } |
| |
| /** |
| * Set up initial values for each of the data flow sets, prior to running |
| * the fixed-point algorithm. |
| */ |
| void |
| fs_copy_prop_dataflow::setup_initial_values() |
| { |
| /* Initialize the COPY and KILL sets. */ |
| { |
| /* Create a temporary table of ACP entries which we'll use for efficient |
| * look-up. Unfortunately, we have to do this in two steps because we |
| * have to match both sources and destinations and an ACP entry can only |
| * be in one list at a time. |
| * |
| * We choose to make the table size between num_acp/2 and num_acp/4 to |
| * try and trade off between the time it takes to initialize the table |
| * via exec_list constructors or make_empty() and the cost of |
| * collisions. In practice, it doesn't appear to matter too much what |
| * size we make the table as long as it's roughly the same order of |
| * magnitude as num_acp. We get most of the benefit of the table |
| * approach even if we use a table of size ACP_HASH_SIZE though a |
| * full-sized table is 1-2% faster in practice. |
| */ |
| unsigned acp_table_size = util_next_power_of_two(num_acp) / 4; |
| acp_table_size = MAX2(acp_table_size, ACP_HASH_SIZE); |
| exec_list *acp_table = new exec_list[acp_table_size]; |
| |
| /* First, get all the KILLs for instructions which overwrite ACP |
| * destinations. |
| */ |
| for (int i = 0; i < num_acp; i++) { |
| unsigned idx = reg_space(acp[i]->dst) & (acp_table_size - 1); |
| acp_table[idx].push_tail(acp[i]); |
| } |
| |
| foreach_block (block, cfg) { |
| foreach_inst_in_block(fs_inst, inst, block) { |
| if (inst->dst.file != VGRF) |
| continue; |
| |
| unsigned idx = reg_space(inst->dst) & (acp_table_size - 1); |
| foreach_in_list(acp_entry, entry, &acp_table[idx]) { |
| if (regions_overlap(inst->dst, inst->size_written, |
| entry->dst, entry->size_written)) |
| BITSET_SET(bd[block->num].kill, entry->global_idx); |
| } |
| } |
| } |
| |
| /* Clear the table for the second pass */ |
| for (unsigned i = 0; i < acp_table_size; i++) |
| acp_table[i].make_empty(); |
| |
| /* Next, get all the KILLs for instructions which overwrite ACP |
| * sources. |
| */ |
| for (int i = 0; i < num_acp; i++) { |
| unsigned idx = reg_space(acp[i]->src) & (acp_table_size - 1); |
| acp_table[idx].push_tail(acp[i]); |
| } |
| |
| foreach_block (block, cfg) { |
| foreach_inst_in_block(fs_inst, inst, block) { |
| if (inst->dst.file != VGRF && |
| inst->dst.file != FIXED_GRF) |
| continue; |
| |
| unsigned idx = reg_space(inst->dst) & (acp_table_size - 1); |
| foreach_in_list(acp_entry, entry, &acp_table[idx]) { |
| if (regions_overlap(inst->dst, inst->size_written, |
| entry->src, entry->size_read)) |
| BITSET_SET(bd[block->num].kill, entry->global_idx); |
| } |
| } |
| } |
| |
| delete [] acp_table; |
| } |
| |
| /* Populate the initial values for the livein and liveout sets. For the |
| * block at the start of the program, livein = 0 and liveout = copy. |
| * For the others, set liveout and livein to ~0 (the universal set). |
| */ |
| foreach_block (block, cfg) { |
| if (block->parents.is_empty()) { |
| for (int i = 0; i < bitset_words; i++) { |
| bd[block->num].livein[i] = 0u; |
| bd[block->num].liveout[i] = bd[block->num].copy[i]; |
| } |
| } else { |
| for (int i = 0; i < bitset_words; i++) { |
| bd[block->num].liveout[i] = ~0u; |
| bd[block->num].livein[i] = ~0u; |
| } |
| } |
| } |
| |
| /* Initialize the undef set. */ |
| foreach_block (block, cfg) { |
| for (int i = 0; i < num_acp; i++) { |
| BITSET_SET(bd[block->num].undef, i); |
| for (unsigned off = 0; off < acp[i]->size_written; off += REG_SIZE) { |
| if (BITSET_TEST(live.block_data[block->num].defout, |
| live.var_from_reg(byte_offset(acp[i]->dst, off)))) |
| BITSET_CLEAR(bd[block->num].undef, i); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Walk the set of instructions in the block, marking which entries in the acp |
| * are killed by the block. |
| */ |
| void |
| fs_copy_prop_dataflow::run() |
| { |
| bool progress; |
| |
| do { |
| progress = false; |
| |
| foreach_block (block, cfg) { |
| if (block->parents.is_empty()) |
| continue; |
| |
| for (int i = 0; i < bitset_words; i++) { |
| const BITSET_WORD old_liveout = bd[block->num].liveout[i]; |
| BITSET_WORD livein_from_any_block = 0; |
| |
| /* Update livein for this block. If a copy is live out of all |
| * parent blocks, it's live coming in to this block. |
| */ |
| bd[block->num].livein[i] = ~0u; |
| foreach_list_typed(bblock_link, parent_link, link, &block->parents) { |
| bblock_t *parent = parent_link->block; |
| /* Consider ACP entries with a known-undefined destination to |
| * be available from the parent. This is valid because we're |
| * free to set the undefined variable equal to the source of |
| * the ACP entry without breaking the application's |
| * expectations, since the variable is undefined. |
| */ |
| bd[block->num].livein[i] &= (bd[parent->num].liveout[i] | |
| bd[parent->num].undef[i]); |
| livein_from_any_block |= bd[parent->num].liveout[i]; |
| } |
| |
| /* Limit to the set of ACP entries that can possibly be available |
| * at the start of the block, since propagating from a variable |
| * which is guaranteed to be undefined (rather than potentially |
| * undefined for some dynamic control-flow paths) doesn't seem |
| * particularly useful. |
| */ |
| bd[block->num].livein[i] &= livein_from_any_block; |
| |
| /* Update liveout for this block. */ |
| bd[block->num].liveout[i] = |
| bd[block->num].copy[i] | (bd[block->num].livein[i] & |
| ~bd[block->num].kill[i]); |
| |
| if (old_liveout != bd[block->num].liveout[i]) |
| progress = true; |
| } |
| } |
| } while (progress); |
| } |
| |
| void |
| fs_copy_prop_dataflow::dump_block_data() const |
| { |
| foreach_block (block, cfg) { |
| fprintf(stderr, "Block %d [%d, %d] (parents ", block->num, |
| block->start_ip, block->end_ip); |
| foreach_list_typed(bblock_link, link, link, &block->parents) { |
| bblock_t *parent = link->block; |
| fprintf(stderr, "%d ", parent->num); |
| } |
| fprintf(stderr, "):\n"); |
| fprintf(stderr, " livein = 0x"); |
| for (int i = 0; i < bitset_words; i++) |
| fprintf(stderr, "%08x", bd[block->num].livein[i]); |
| fprintf(stderr, ", liveout = 0x"); |
| for (int i = 0; i < bitset_words; i++) |
| fprintf(stderr, "%08x", bd[block->num].liveout[i]); |
| fprintf(stderr, ",\n copy = 0x"); |
| for (int i = 0; i < bitset_words; i++) |
| fprintf(stderr, "%08x", bd[block->num].copy[i]); |
| fprintf(stderr, ", kill = 0x"); |
| for (int i = 0; i < bitset_words; i++) |
| fprintf(stderr, "%08x", bd[block->num].kill[i]); |
| fprintf(stderr, "\n"); |
| } |
| } |
| |
| static bool |
| is_logic_op(enum opcode opcode) |
| { |
| return (opcode == BRW_OPCODE_AND || |
| opcode == BRW_OPCODE_OR || |
| opcode == BRW_OPCODE_XOR || |
| opcode == BRW_OPCODE_NOT); |
| } |
| |
| static bool |
| can_take_stride(fs_inst *inst, unsigned arg, unsigned stride, |
| const gen_device_info *devinfo) |
| { |
| if (stride > 4) |
| return false; |
| |
| /* Bail if the channels of the source need to be aligned to the byte offset |
| * of the corresponding channel of the destination, and the provided stride |
| * would break this restriction. |
| */ |
| if (has_dst_aligned_region_restriction(devinfo, inst) && |
| !(type_sz(inst->src[arg].type) * stride == |
| type_sz(inst->dst.type) * inst->dst.stride || |
| stride == 0)) |
| return false; |
| |
| /* 3-source instructions can only be Align16, which restricts what strides |
| * they can take. They can only take a stride of 1 (the usual case), or 0 |
| * with a special "repctrl" bit. But the repctrl bit doesn't work for |
| * 64-bit datatypes, so if the source type is 64-bit then only a stride of |
| * 1 is allowed. From the Broadwell PRM, Volume 7 "3D Media GPGPU", page |
| * 944: |
| * |
| * This is applicable to 32b datatypes and 16b datatype. 64b datatypes |
| * cannot use the replicate control. |
| */ |
| if (inst->is_3src(devinfo)) { |
| if (type_sz(inst->src[arg].type) > 4) |
| return stride == 1; |
| else |
| return stride == 1 || stride == 0; |
| } |
| |
| /* From the Broadwell PRM, Volume 2a "Command Reference - Instructions", |
| * page 391 ("Extended Math Function"): |
| * |
| * The following restrictions apply for align1 mode: Scalar source is |
| * supported. Source and destination horizontal stride must be the |
| * same. |
| * |
| * From the Haswell PRM Volume 2b "Command Reference - Instructions", page |
| * 134 ("Extended Math Function"): |
| * |
| * Scalar source is supported. Source and destination horizontal stride |
| * must be 1. |
| * |
| * and similar language exists for IVB and SNB. Pre-SNB, math instructions |
| * are sends, so the sources are moved to MRF's and there are no |
| * restrictions. |
| */ |
| if (inst->is_math()) { |
| if (devinfo->gen == 6 || devinfo->gen == 7) { |
| assert(inst->dst.stride == 1); |
| return stride == 1 || stride == 0; |
| } else if (devinfo->gen >= 8) { |
| return stride == inst->dst.stride || stride == 0; |
| } |
| } |
| |
| return true; |
| } |
| |
| static bool |
| instruction_requires_packed_data(fs_inst *inst) |
| { |
| switch (inst->opcode) { |
| case FS_OPCODE_DDX_FINE: |
| case FS_OPCODE_DDX_COARSE: |
| case FS_OPCODE_DDY_FINE: |
| case FS_OPCODE_DDY_COARSE: |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| bool |
| fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry) |
| { |
| if (inst->src[arg].file != VGRF) |
| return false; |
| |
| if (entry->src.file == IMM) |
| return false; |
| assert(entry->src.file == VGRF || entry->src.file == UNIFORM || |
| entry->src.file == ATTR || entry->src.file == FIXED_GRF); |
| |
| /* Avoid propagating a LOAD_PAYLOAD instruction into another if there is a |
| * good chance that we'll be able to eliminate the latter through register |
| * coalescing. If only part of the sources of the second LOAD_PAYLOAD can |
| * be simplified through copy propagation we would be making register |
| * coalescing impossible, ending up with unnecessary copies in the program. |
| * This is also the case for is_multi_copy_payload() copies that can only |
| * be coalesced when the instruction is lowered into a sequence of MOVs. |
| * |
| * Worse -- In cases where the ACP entry was the result of CSE combining |
| * multiple LOAD_PAYLOAD subexpressions, propagating the first LOAD_PAYLOAD |
| * into the second would undo the work of CSE, leading to an infinite |
| * optimization loop. Avoid this by detecting LOAD_PAYLOAD copies from CSE |
| * temporaries which should match is_coalescing_payload(). |
| */ |
| if (entry->opcode == SHADER_OPCODE_LOAD_PAYLOAD && |
| (is_coalescing_payload(alloc, inst) || is_multi_copy_payload(inst))) |
| return false; |
| |
| assert(entry->dst.file == VGRF); |
| if (inst->src[arg].nr != entry->dst.nr) |
| return false; |
| |
| /* Bail if inst is reading a range that isn't contained in the range |
| * that entry is writing. |
| */ |
| if (!region_contained_in(inst->src[arg], inst->size_read(arg), |
| entry->dst, entry->size_written)) |
| return false; |
| |
| /* Avoid propagating a FIXED_GRF register into an EOT instruction in order |
| * for any register allocation restrictions to be applied. |
| */ |
| if (entry->src.file == FIXED_GRF && inst->eot) |
| return false; |
| |
| /* Avoid propagating odd-numbered FIXED_GRF registers into the first source |
| * of a LINTERP instruction on platforms where the PLN instruction has |
| * register alignment restrictions. |
| */ |
| if (devinfo->has_pln && devinfo->gen <= 6 && |
| entry->src.file == FIXED_GRF && (entry->src.nr & 1) && |
| inst->opcode == FS_OPCODE_LINTERP && arg == 0) |
| return false; |
| |
| /* we can't generally copy-propagate UD negations because we |
| * can end up accessing the resulting values as signed integers |
| * instead. See also resolve_ud_negate() and comment in |
| * fs_generator::generate_code. |
| */ |
| if (entry->src.type == BRW_REGISTER_TYPE_UD && |
| entry->src.negate) |
| return false; |
| |
| bool has_source_modifiers = entry->src.abs || entry->src.negate; |
| |
| if ((has_source_modifiers || entry->src.file == UNIFORM || |
| !entry->src.is_contiguous()) && |
| !inst->can_do_source_mods(devinfo)) |
| return false; |
| |
| if (has_source_modifiers && |
| inst->opcode == SHADER_OPCODE_GEN4_SCRATCH_WRITE) |
| return false; |
| |
| /* Some instructions implemented in the generator backend, such as |
| * derivatives, assume that their operands are packed so we can't |
| * generally propagate strided regions to them. |
| */ |
| const unsigned entry_stride = (entry->src.file == FIXED_GRF ? 1 : |
| entry->src.stride); |
| if (instruction_requires_packed_data(inst) && entry_stride != 1) |
| return false; |
| |
| /* Bail if the result of composing both strides would exceed the |
| * hardware limit. |
| */ |
| if (!can_take_stride(inst, arg, entry_stride * inst->src[arg].stride, |
| devinfo)) |
| return false; |
| |
| /* Bail if the source FIXED_GRF region of the copy cannot be trivially |
| * composed with the source region of the instruction -- E.g. because the |
| * copy uses some extended stride greater than 4 not supported natively by |
| * the hardware as a horizontal stride, or because instruction compression |
| * could require us to use a vertical stride shorter than a GRF. |
| */ |
| if (entry->src.file == FIXED_GRF && |
| (inst->src[arg].stride > 4 || |
| inst->dst.component_size(inst->exec_size) > |
| inst->src[arg].component_size(inst->exec_size))) |
| return false; |
| |
| /* Bail if the instruction type is larger than the execution type of the |
| * copy, what implies that each channel is reading multiple channels of the |
| * destination of the copy, and simply replacing the sources would give a |
| * program with different semantics. |
| */ |
| if (type_sz(entry->dst.type) < type_sz(inst->src[arg].type)) |
| return false; |
| |
| /* Bail if the result of composing both strides cannot be expressed |
| * as another stride. This avoids, for example, trying to transform |
| * this: |
| * |
| * MOV (8) rX<1>UD rY<0;1,0>UD |
| * FOO (8) ... rX<8;8,1>UW |
| * |
| * into this: |
| * |
| * FOO (8) ... rY<0;1,0>UW |
| * |
| * Which would have different semantics. |
| */ |
| if (entry_stride != 1 && |
| (inst->src[arg].stride * |
| type_sz(inst->src[arg].type)) % type_sz(entry->src.type) != 0) |
| return false; |
| |
| /* Since semantics of source modifiers are type-dependent we need to |
| * ensure that the meaning of the instruction remains the same if we |
| * change the type. If the sizes of the types are different the new |
| * instruction will read a different amount of data than the original |
| * and the semantics will always be different. |
| */ |
| if (has_source_modifiers && |
| entry->dst.type != inst->src[arg].type && |
| (!inst->can_change_types() || |
| type_sz(entry->dst.type) != type_sz(inst->src[arg].type))) |
| return false; |
| |
| if (devinfo->gen >= 8 && (entry->src.negate || entry->src.abs) && |
| is_logic_op(inst->opcode)) { |
| return false; |
| } |
| |
| if (entry->saturate) { |
| switch(inst->opcode) { |
| case BRW_OPCODE_SEL: |
| if ((inst->conditional_mod != BRW_CONDITIONAL_GE && |
| inst->conditional_mod != BRW_CONDITIONAL_L) || |
| inst->src[1].file != IMM || |
| inst->src[1].f < 0.0 || |
| inst->src[1].f > 1.0) { |
| return false; |
| } |
| break; |
| default: |
| return false; |
| } |
| } |
| |
| /* Save the offset of inst->src[arg] relative to entry->dst for it to be |
| * applied later. |
| */ |
| const unsigned rel_offset = inst->src[arg].offset - entry->dst.offset; |
| |
| /* Fold the copy into the instruction consuming it. */ |
| inst->src[arg].file = entry->src.file; |
| inst->src[arg].nr = entry->src.nr; |
| inst->src[arg].subnr = entry->src.subnr; |
| inst->src[arg].offset = entry->src.offset; |
| |
| /* Compose the strides of both regions. */ |
| if (entry->src.file == FIXED_GRF) { |
| if (inst->src[arg].stride) { |
| const unsigned orig_width = 1 << entry->src.width; |
| const unsigned reg_width = REG_SIZE / (type_sz(inst->src[arg].type) * |
| inst->src[arg].stride); |
| inst->src[arg].width = cvt(MIN2(orig_width, reg_width)) - 1; |
| inst->src[arg].hstride = cvt(inst->src[arg].stride); |
| inst->src[arg].vstride = inst->src[arg].hstride + inst->src[arg].width; |
| } else { |
| inst->src[arg].vstride = inst->src[arg].hstride = |
| inst->src[arg].width = 0; |
| } |
| |
| inst->src[arg].stride = 1; |
| |
| /* Hopefully no Align16 around here... */ |
| assert(entry->src.swizzle == BRW_SWIZZLE_XYZW); |
| inst->src[arg].swizzle = entry->src.swizzle; |
| } else { |
| inst->src[arg].stride *= entry->src.stride; |
| } |
| |
| /* Compose any saturate modifiers. */ |
| inst->saturate = inst->saturate || entry->saturate; |
| |
| /* Compute the first component of the copy that the instruction is |
| * reading, and the base byte offset within that component. |
| */ |
| assert(entry->dst.offset % REG_SIZE == 0 && entry->dst.stride == 1); |
| const unsigned component = rel_offset / type_sz(entry->dst.type); |
| const unsigned suboffset = rel_offset % type_sz(entry->dst.type); |
| |
| /* Calculate the byte offset at the origin of the copy of the given |
| * component and suboffset. |
| */ |
| inst->src[arg] = byte_offset(inst->src[arg], |
| component * entry_stride * type_sz(entry->src.type) + suboffset); |
| |
| if (has_source_modifiers) { |
| if (entry->dst.type != inst->src[arg].type) { |
| /* We are propagating source modifiers from a MOV with a different |
| * type. If we got here, then we can just change the source and |
| * destination types of the instruction and keep going. |
| */ |
| assert(inst->can_change_types()); |
| for (int i = 0; i < inst->sources; i++) { |
| inst->src[i].type = entry->dst.type; |
| } |
| inst->dst.type = entry->dst.type; |
| } |
| |
| if (!inst->src[arg].abs) { |
| inst->src[arg].abs = entry->src.abs; |
| inst->src[arg].negate ^= entry->src.negate; |
| } |
| } |
| |
| return true; |
| } |
| |
| |
| bool |
| fs_visitor::try_constant_propagate(fs_inst *inst, acp_entry *entry) |
| { |
| bool progress = false; |
| |
| if (entry->src.file != IMM) |
| return false; |
| if (type_sz(entry->src.type) > 4) |
| return false; |
| if (entry->saturate) |
| return false; |
| |
| for (int i = inst->sources - 1; i >= 0; i--) { |
| if (inst->src[i].file != VGRF) |
| continue; |
| |
| assert(entry->dst.file == VGRF); |
| if (inst->src[i].nr != entry->dst.nr) |
| continue; |
| |
| /* Bail if inst is reading a range that isn't contained in the range |
| * that entry is writing. |
| */ |
| if (!region_contained_in(inst->src[i], inst->size_read(i), |
| entry->dst, entry->size_written)) |
| continue; |
| |
| /* If the type sizes don't match each channel of the instruction is |
| * either extracting a portion of the constant (which could be handled |
| * with some effort but the code below doesn't) or reading multiple |
| * channels of the source at once. |
| */ |
| if (type_sz(inst->src[i].type) != type_sz(entry->dst.type)) |
| continue; |
| |
| fs_reg val = entry->src; |
| val.type = inst->src[i].type; |
| |
| if (inst->src[i].abs) { |
| if ((devinfo->gen >= 8 && is_logic_op(inst->opcode)) || |
| !brw_abs_immediate(val.type, &val.as_brw_reg())) { |
| continue; |
| } |
| } |
| |
| if (inst->src[i].negate) { |
| if ((devinfo->gen >= 8 && is_logic_op(inst->opcode)) || |
| !brw_negate_immediate(val.type, &val.as_brw_reg())) { |
| continue; |
| } |
| } |
| |
| switch (inst->opcode) { |
| case BRW_OPCODE_MOV: |
| case SHADER_OPCODE_LOAD_PAYLOAD: |
| case FS_OPCODE_PACK: |
| inst->src[i] = val; |
| progress = true; |
| break; |
| |
| case SHADER_OPCODE_INT_QUOTIENT: |
| case SHADER_OPCODE_INT_REMAINDER: |
| /* FINISHME: Promote non-float constants and remove this. */ |
| if (devinfo->gen < 8) |
| break; |
| /* fallthrough */ |
| case SHADER_OPCODE_POW: |
| /* Allow constant propagation into src1 (except on Gen 6 which |
| * doesn't support scalar source math), and let constant combining |
| * promote the constant on Gen < 8. |
| */ |
| if (devinfo->gen == 6) |
| break; |
| /* fallthrough */ |
| case BRW_OPCODE_BFI1: |
| case BRW_OPCODE_ASR: |
| case BRW_OPCODE_SHL: |
| case BRW_OPCODE_SHR: |
| case BRW_OPCODE_SUBB: |
| if (i == 1) { |
| inst->src[i] = val; |
| progress = true; |
| } |
| break; |
| |
| case BRW_OPCODE_MACH: |
| case BRW_OPCODE_MUL: |
| case SHADER_OPCODE_MULH: |
| case BRW_OPCODE_ADD: |
| case BRW_OPCODE_OR: |
| case BRW_OPCODE_AND: |
| case BRW_OPCODE_XOR: |
| case BRW_OPCODE_ADDC: |
| if (i == 1) { |
| inst->src[i] = val; |
| progress = true; |
| } else if (i == 0 && inst->src[1].file != IMM) { |
| /* Fit this constant in by commuting the operands. |
| * Exception: we can't do this for 32-bit integer MUL/MACH |
| * because it's asymmetric. |
| * |
| * The BSpec says for Broadwell that |
| * |
| * "When multiplying DW x DW, the dst cannot be accumulator." |
| * |
| * Integer MUL with a non-accumulator destination will be lowered |
| * by lower_integer_multiplication(), so don't restrict it. |
| */ |
| if (((inst->opcode == BRW_OPCODE_MUL && |
| inst->dst.is_accumulator()) || |
| inst->opcode == BRW_OPCODE_MACH) && |
| (inst->src[1].type == BRW_REGISTER_TYPE_D || |
| inst->src[1].type == BRW_REGISTER_TYPE_UD)) |
| break; |
| inst->src[0] = inst->src[1]; |
| inst->src[1] = val; |
| progress = true; |
| } |
| break; |
| |
| case BRW_OPCODE_CMP: |
| case BRW_OPCODE_IF: |
| if (i == 1) { |
| inst->src[i] = val; |
| progress = true; |
| } else if (i == 0 && inst->src[1].file != IMM) { |
| enum brw_conditional_mod new_cmod; |
| |
| new_cmod = brw_swap_cmod(inst->conditional_mod); |
| if (new_cmod != BRW_CONDITIONAL_NONE) { |
| /* Fit this constant in by swapping the operands and |
| * flipping the test |
| */ |
| inst->src[0] = inst->src[1]; |
| inst->src[1] = val; |
| inst->conditional_mod = new_cmod; |
| progress = true; |
| } |
| } |
| break; |
| |
| case BRW_OPCODE_SEL: |
| if (i == 1) { |
| inst->src[i] = val; |
| progress = true; |
| } else if (i == 0 && inst->src[1].file != IMM && |
| (inst->conditional_mod == BRW_CONDITIONAL_NONE || |
| /* Only GE and L are commutative. */ |
| inst->conditional_mod == BRW_CONDITIONAL_GE || |
| inst->conditional_mod == BRW_CONDITIONAL_L)) { |
| inst->src[0] = inst->src[1]; |
| inst->src[1] = val; |
| |
| /* If this was predicated, flipping operands means |
| * we also need to flip the predicate. |
| */ |
| if (inst->conditional_mod == BRW_CONDITIONAL_NONE) { |
| inst->predicate_inverse = |
| !inst->predicate_inverse; |
| } |
| progress = true; |
| } |
| break; |
| |
| case FS_OPCODE_FB_WRITE_LOGICAL: |
| /* The stencil and omask sources of FS_OPCODE_FB_WRITE_LOGICAL are |
| * bit-cast using a strided region so they cannot be immediates. |
| */ |
| if (i != FB_WRITE_LOGICAL_SRC_SRC_STENCIL && |
| i != FB_WRITE_LOGICAL_SRC_OMASK) { |
| inst->src[i] = val; |
| progress = true; |
| } |
| break; |
| |
| case SHADER_OPCODE_TEX_LOGICAL: |
| case SHADER_OPCODE_TXD_LOGICAL: |
| case SHADER_OPCODE_TXF_LOGICAL: |
| case SHADER_OPCODE_TXL_LOGICAL: |
| case SHADER_OPCODE_TXS_LOGICAL: |
| case FS_OPCODE_TXB_LOGICAL: |
| case SHADER_OPCODE_TXF_CMS_LOGICAL: |
| case SHADER_OPCODE_TXF_CMS_W_LOGICAL: |
| case SHADER_OPCODE_TXF_UMS_LOGICAL: |
| case SHADER_OPCODE_TXF_MCS_LOGICAL: |
| case SHADER_OPCODE_LOD_LOGICAL: |
| case SHADER_OPCODE_TG4_LOGICAL: |
| case SHADER_OPCODE_TG4_OFFSET_LOGICAL: |
| case SHADER_OPCODE_SAMPLEINFO_LOGICAL: |
| case SHADER_OPCODE_IMAGE_SIZE_LOGICAL: |
| case SHADER_OPCODE_UNTYPED_ATOMIC_LOGICAL: |
| case SHADER_OPCODE_UNTYPED_ATOMIC_FLOAT_LOGICAL: |
| case SHADER_OPCODE_UNTYPED_SURFACE_READ_LOGICAL: |
| case SHADER_OPCODE_UNTYPED_SURFACE_WRITE_LOGICAL: |
| case SHADER_OPCODE_TYPED_ATOMIC_LOGICAL: |
| case SHADER_OPCODE_TYPED_SURFACE_READ_LOGICAL: |
| case SHADER_OPCODE_TYPED_SURFACE_WRITE_LOGICAL: |
| case SHADER_OPCODE_BYTE_SCATTERED_WRITE_LOGICAL: |
| case SHADER_OPCODE_BYTE_SCATTERED_READ_LOGICAL: |
| inst->src[i] = val; |
| progress = true; |
| break; |
| |
| case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD: |
| case SHADER_OPCODE_BROADCAST: |
| inst->src[i] = val; |
| progress = true; |
| break; |
| |
| case BRW_OPCODE_MAD: |
| case BRW_OPCODE_LRP: |
| inst->src[i] = val; |
| progress = true; |
| break; |
| |
| default: |
| break; |
| } |
| } |
| |
| return progress; |
| } |
| |
| static bool |
| can_propagate_from(fs_inst *inst) |
| { |
| return (inst->opcode == BRW_OPCODE_MOV && |
| inst->dst.file == VGRF && |
| ((inst->src[0].file == VGRF && |
| !regions_overlap(inst->dst, inst->size_written, |
| inst->src[0], inst->size_read(0))) || |
| inst->src[0].file == ATTR || |
| inst->src[0].file == UNIFORM || |
| inst->src[0].file == IMM || |
| (inst->src[0].file == FIXED_GRF && |
| inst->src[0].is_contiguous())) && |
| inst->src[0].type == inst->dst.type && |
| !inst->is_partial_write()) || |
| is_identity_payload(FIXED_GRF, inst); |
| } |
| |
| /* Walks a basic block and does copy propagation on it using the acp |
| * list. |
| */ |
| bool |
| fs_visitor::opt_copy_propagation_local(void *copy_prop_ctx, bblock_t *block, |
| exec_list *acp) |
| { |
| bool progress = false; |
| |
| foreach_inst_in_block(fs_inst, inst, block) { |
| /* Try propagating into this instruction. */ |
| for (int i = 0; i < inst->sources; i++) { |
| if (inst->src[i].file != VGRF) |
| continue; |
| |
| foreach_in_list(acp_entry, entry, &acp[inst->src[i].nr % ACP_HASH_SIZE]) { |
| if (try_constant_propagate(inst, entry)) |
| progress = true; |
| else if (try_copy_propagate(inst, i, entry)) |
| progress = true; |
| } |
| } |
| |
| /* kill the destination from the ACP */ |
| if (inst->dst.file == VGRF || inst->dst.file == FIXED_GRF) { |
| foreach_in_list_safe(acp_entry, entry, &acp[inst->dst.nr % ACP_HASH_SIZE]) { |
| if (regions_overlap(entry->dst, entry->size_written, |
| inst->dst, inst->size_written)) |
| entry->remove(); |
| } |
| |
| /* Oops, we only have the chaining hash based on the destination, not |
| * the source, so walk across the entire table. |
| */ |
| for (int i = 0; i < ACP_HASH_SIZE; i++) { |
| foreach_in_list_safe(acp_entry, entry, &acp[i]) { |
| /* Make sure we kill the entry if this instruction overwrites |
| * _any_ of the registers that it reads |
| */ |
| if (regions_overlap(entry->src, entry->size_read, |
| inst->dst, inst->size_written)) |
| entry->remove(); |
| } |
| } |
| } |
| |
| /* If this instruction's source could potentially be folded into the |
| * operand of another instruction, add it to the ACP. |
| */ |
| if (can_propagate_from(inst)) { |
| acp_entry *entry = rzalloc(copy_prop_ctx, acp_entry); |
| entry->dst = inst->dst; |
| entry->src = inst->src[0]; |
| entry->size_written = inst->size_written; |
| for (unsigned i = 0; i < inst->sources; i++) |
| entry->size_read += inst->size_read(i); |
| entry->opcode = inst->opcode; |
| entry->saturate = inst->saturate; |
| acp[entry->dst.nr % ACP_HASH_SIZE].push_tail(entry); |
| } else if (inst->opcode == SHADER_OPCODE_LOAD_PAYLOAD && |
| inst->dst.file == VGRF) { |
| int offset = 0; |
| for (int i = 0; i < inst->sources; i++) { |
| int effective_width = i < inst->header_size ? 8 : inst->exec_size; |
| assert(effective_width * type_sz(inst->src[i].type) % REG_SIZE == 0); |
| const unsigned size_written = effective_width * |
| type_sz(inst->src[i].type); |
| if (inst->src[i].file == VGRF || |
| (inst->src[i].file == FIXED_GRF && |
| inst->src[i].is_contiguous())) { |
| acp_entry *entry = rzalloc(copy_prop_ctx, acp_entry); |
| entry->dst = byte_offset(inst->dst, offset); |
| entry->src = inst->src[i]; |
| entry->size_written = size_written; |
| entry->size_read = inst->size_read(i); |
| entry->opcode = inst->opcode; |
| if (!entry->dst.equals(inst->src[i])) { |
| acp[entry->dst.nr % ACP_HASH_SIZE].push_tail(entry); |
| } else { |
| ralloc_free(entry); |
| } |
| } |
| offset += size_written; |
| } |
| } |
| } |
| |
| return progress; |
| } |
| |
| bool |
| fs_visitor::opt_copy_propagation() |
| { |
| bool progress = false; |
| void *copy_prop_ctx = ralloc_context(NULL); |
| exec_list *out_acp[cfg->num_blocks]; |
| |
| for (int i = 0; i < cfg->num_blocks; i++) |
| out_acp[i] = new exec_list [ACP_HASH_SIZE]; |
| |
| const fs_live_variables &live = live_analysis.require(); |
| |
| /* First, walk through each block doing local copy propagation and getting |
| * the set of copies available at the end of the block. |
| */ |
| foreach_block (block, cfg) { |
| progress = opt_copy_propagation_local(copy_prop_ctx, block, |
| out_acp[block->num]) || progress; |
| |
| /* If the destination of an ACP entry exists only within this block, |
| * then there's no need to keep it for dataflow analysis. We can delete |
| * it from the out_acp table and avoid growing the bitsets any bigger |
| * than we absolutely have to. |
| * |
| * Because nothing in opt_copy_propagation_local touches the block |
| * start/end IPs and opt_copy_propagation_local is incapable of |
| * extending the live range of an ACP destination beyond the block, |
| * it's safe to use the liveness information in this way. |
| */ |
| for (unsigned a = 0; a < ACP_HASH_SIZE; a++) { |
| foreach_in_list_safe(acp_entry, entry, &out_acp[block->num][a]) { |
| assert(entry->dst.file == VGRF); |
| if (block->start_ip <= live.vgrf_start[entry->dst.nr] && |
| live.vgrf_end[entry->dst.nr] <= block->end_ip) |
| entry->remove(); |
| } |
| } |
| } |
| |
| /* Do dataflow analysis for those available copies. */ |
| fs_copy_prop_dataflow dataflow(copy_prop_ctx, cfg, live, out_acp); |
| |
| /* Next, re-run local copy propagation, this time with the set of copies |
| * provided by the dataflow analysis available at the start of a block. |
| */ |
| foreach_block (block, cfg) { |
| exec_list in_acp[ACP_HASH_SIZE]; |
| |
| for (int i = 0; i < dataflow.num_acp; i++) { |
| if (BITSET_TEST(dataflow.bd[block->num].livein, i)) { |
| struct acp_entry *entry = dataflow.acp[i]; |
| in_acp[entry->dst.nr % ACP_HASH_SIZE].push_tail(entry); |
| } |
| } |
| |
| progress = opt_copy_propagation_local(copy_prop_ctx, block, in_acp) || |
| progress; |
| } |
| |
| for (int i = 0; i < cfg->num_blocks; i++) |
| delete [] out_acp[i]; |
| ralloc_free(copy_prop_ctx); |
| |
| if (progress) |
| invalidate_analysis(DEPENDENCY_INSTRUCTION_DATA_FLOW | |
| DEPENDENCY_INSTRUCTION_DETAIL); |
| |
| return progress; |
| } |