* 12.5 (p356).
*/
-#define ACP_HASH_SIZE 16
+#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"
struct acp_entry : public exec_node {
fs_reg dst;
fs_reg src;
- uint8_t size_written;
- uint8_t size_read;
+ unsigned global_idx;
+ unsigned size_written;
+ unsigned size_read;
enum opcode opcode;
bool saturate;
};
{
public:
fs_copy_prop_dataflow(void *mem_ctx, cfg_t *cfg,
- const fs_live_variables *live,
+ const fs_live_variables &live,
exec_list *out_acp[ACP_HASH_SIZE]);
void setup_initial_values();
void *mem_ctx;
cfg_t *cfg;
- const fs_live_variables *live;
+ const fs_live_variables &live;
acp_entry **acp;
int num_acp;
} /* anonymous namespace */
fs_copy_prop_dataflow::fs_copy_prop_dataflow(void *mem_ctx, cfg_t *cfg,
- const fs_live_variables *live,
+ const fs_live_variables &live,
exec_list *out_acp[ACP_HASH_SIZE])
: mem_ctx(mem_ctx), cfg(cfg), live(live)
{
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.
fs_copy_prop_dataflow::setup_initial_values()
{
/* Initialize the COPY and KILL sets. */
- foreach_block (block, cfg) {
- foreach_inst_in_block(fs_inst, inst, block) {
- if (inst->dst.file != VGRF)
- continue;
+ {
+ /* 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];
- /* Mark ACP entries which are killed by this instruction. */
- for (int i = 0; i < num_acp; i++) {
- if (regions_overlap(inst->dst, inst->size_written,
- acp[i]->dst, acp[i]->size_written) ||
- regions_overlap(inst->dst, inst->size_written,
- acp[i]->src, acp[i]->size_read)) {
- BITSET_SET(bd[block->num].kill, i);
+ /* 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
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))))
+ 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);
}
}
if (entry->src.file == IMM)
return false;
assert(entry->src.file == VGRF || entry->src.file == UNIFORM ||
- entry->src.file == ATTR);
-
+ 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 &&
- inst->opcode == SHADER_OPCODE_LOAD_PAYLOAD)
+ (is_coalescing_payload(alloc, inst) || is_multi_copy_payload(inst)))
return false;
assert(entry->dst.file == VGRF);
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
* derivatives, assume that their operands are packed so we can't
* generally propagate strided regions to them.
*/
- if (instruction_requires_packed_data(inst) && entry->src.stride > 1)
+ 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->src.stride * inst->src[arg].stride,
+ 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
*
* Which would have different semantics.
*/
- if (entry->src.stride != 1 &&
+ if (entry_stride != 1 &&
(inst->src[arg].stride *
type_sz(inst->src[arg].type)) % type_sz(entry->src.type) != 0)
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].stride *= entry->src.stride;
- inst->saturate = inst->saturate || entry->saturate;
+ 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;
+ }
- /* Compute the offset of inst->src[arg] relative to entry->dst */
- const unsigned rel_offset = inst->src[arg].offset - entry->dst.offset;
+ 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.stride == 1);
+ 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].offset = suboffset +
- component * entry->src.stride * type_sz(entry->src.type) +
- entry->src.offset;
+ 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) {
if (i == 1) {
inst->src[i] = val;
progress = true;
- } else if (i == 0 && inst->src[1].file != IMM) {
+ } 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;
}
static bool
-can_propagate_from(fs_inst *inst, unsigned dispatch_width)
+can_propagate_from(fs_inst *inst)
{
return (inst->opcode == BRW_OPCODE_MOV &&
inst->dst.file == VGRF &&
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 == IMM ||
+ (inst->src[0].file == FIXED_GRF &&
+ inst->src[0].is_contiguous())) &&
inst->src[0].type == inst->dst.type &&
- !inst->is_partial_var_write(dispatch_width));
+ !inst->is_partial_write()) ||
+ is_identity_payload(FIXED_GRF, inst);
}
/* Walks a basic block and does copy propagation on it using the acp
}
/* kill the destination from the ACP */
- if (inst->dst.file == VGRF) {
+ 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))
/* 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, dispatch_width)) {
- acp_entry *entry = ralloc(copy_prop_ctx, acp_entry);
+ 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;
- entry->size_read = inst->size_read(0);
+ 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);
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) {
+ 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];
for (int i = 0; i < cfg->num_blocks; i++)
out_acp[i] = new exec_list [ACP_HASH_SIZE];
- calculate_live_intervals();
+ 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_intervals, out_acp);
+ 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.
ralloc_free(copy_prop_ctx);
if (progress)
- invalidate_live_intervals();
+ invalidate_analysis(DEPENDENCY_INSTRUCTION_DATA_FLOW |
+ DEPENDENCY_INSTRUCTION_DETAIL);
return progress;
}
projects / mesa.git / blobdiff