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aco/ra: try more aggressive to assign phi defs the same register 

Totals from 4158 (2.77% of 150170) affected shaders: (GFX10.3)
VGPRs: 312008 -> 312000 (-0.00%)
CodeSize: 42902064 -> 42892200 (-0.02%); split: -0.06%, +0.04%
Instrs: 8086443 -> 8084532 (-0.02%); split: -0.07%, +0.05%
Latency: 138551153 -> 138215222 (-0.24%); split: -0.28%, +0.03%
InvThroughput: 39676773 -> 39570850 (-0.27%); split: -0.29%, +0.02%
SClause: 306299 -> 306284 (-0.00%); split: -0.01%, +0.00%
Copies: 552481 -> 553353 (+0.16%); split: -0.75%, +0.91%
Branches: 284381 -> 282409 (-0.69%); split: -0.74%, +0.04%

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12836>
This commit is contained in:
Daniel Schürmann 2021-09-06 14:47:21 +02:00 committed by Marge Bot
parent 28fe49c35f
commit 8995599c80
1 changed files with 27 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
src/amd/compiler/aco_register_allocation.cpp
View File

@ -1915,6 +1915,32 @@ void
get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
std::vector<aco_ptr<Instruction>>& instructions, IDSet& live_in)
{
/* assign phis with matching registers to that register */
for (aco_ptr<Instruction>& phi : block.instructions) {
if (!is_phi(phi))
break;
Definition& definition = phi->definitions[0];
if (definition.isKill() || definition.isFixed())
continue;
if (!phi->operands[0].isTemp())
continue;
PhysReg reg = phi->operands[0].physReg();
auto OpsSame = [=](const Operand& op) -> bool
{ return op.isTemp() && (!op.isFixed() || op.physReg() == reg); };
bool all_same = std::all_of(phi->operands.cbegin() + 1, phi->operands.cend(), OpsSame);
if (!all_same)
continue;
if (!get_reg_specified(ctx, register_file, definition.regClass(), phi, reg))
continue;
definition.setFixed(reg);
register_file.fill(definition);
ctx.assignments[definition.tempId()].set(definition);
}
/* look up the affinities */
for (aco_ptr<Instruction>& phi : block.instructions) {
if (!is_phi(phi))
@ -1928,15 +1954,6 @@ get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
assignment& affinity = ctx.assignments[ctx.assignments[definition.tempId()].affinity];
assert(affinity.rc == definition.regClass());
PhysReg reg = affinity.reg;
if (reg == scc) {
/* only use scc if all operands are already placed there */
bool use_scc = std::all_of(phi->operands.begin(), phi->operands.end(),
[](const Operand& op) {
return op.isTemp() && op.isFixed() && op.physReg() == scc;
});
if (!use_scc)
continue;
}
/* only assign if register is still free */
if (!register_file.test(reg, definition.bytes())) {
@ -1964,10 +1981,8 @@ get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
const Operand& op = phi->operands[i];
if (!op.isTemp() || !op.isFixed())
continue;
PhysReg reg = op.physReg();
/* we tried this already on the previous loop */
if (reg == scc)
continue;
if (get_reg_specified(ctx, register_file, definition.regClass(), phi, reg)) {
definition.setFixed(reg);
break;