Mesa (master): aco: ignore parallelcopies to the same register on jump threading
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Thu Jan 16 15:26:41 UTC 2020
Module: Mesa
Branch: master
Commit: 3bca0af25dbf6d6b162463138100abb20bc1a1cc
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=3bca0af25dbf6d6b162463138100abb20bc1a1cc
Author: Daniel Schürmann <daniel at schuermann.dev>
Date: Tue Jan 14 13:14:38 2020 +0100
aco: ignore parallelcopies to the same register on jump threading
The more conservative lowering to CSSA inserts unnecessary parallelcopies
which might get coalesced and can be ignored on jump threading.
v2: outline is_empty_block() check.
Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3385>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3385>
---
src/amd/compiler/aco_ssa_elimination.cpp | 69 ++++++++++++++++++--------------
1 file changed, 38 insertions(+), 31 deletions(-)
diff --git a/src/amd/compiler/aco_ssa_elimination.cpp b/src/amd/compiler/aco_ssa_elimination.cpp
index 95e2e842a9c..94f5a1ade83 100644
--- a/src/amd/compiler/aco_ssa_elimination.cpp
+++ b/src/amd/compiler/aco_ssa_elimination.cpp
@@ -111,6 +111,35 @@ void insert_parallelcopies(ssa_elimination_ctx& ctx)
}
}
+bool is_empty_block(Block* block, bool ignore_exec_writes)
+{
+ /* check if this block is empty and the exec mask is not needed */
+ for (aco_ptr<Instruction>& instr : block->instructions) {
+ switch (instr->opcode) {
+ case aco_opcode::p_linear_phi:
+ case aco_opcode::p_phi:
+ case aco_opcode::p_logical_start:
+ case aco_opcode::p_logical_end:
+ case aco_opcode::p_branch:
+ break;
+ case aco_opcode::p_parallelcopy:
+ for (unsigned i = 0; i < instr->definitions.size(); i++) {
+ if (ignore_exec_writes && instr->definitions[i].physReg() == exec)
+ continue;
+ if (instr->definitions[i].physReg() != instr->operands[i].physReg())
+ return false;
+ }
+ break;
+ case aco_opcode::s_andn2_b64:
+ case aco_opcode::s_andn2_b32:
+ if (ignore_exec_writes && instr->definitions[0].physReg() == exec)
+ break;
+ default:
+ return false;
+ }
+ }
+ return true;
+}
void try_remove_merge_block(ssa_elimination_ctx& ctx, Block* block)
{
@@ -120,22 +149,9 @@ void try_remove_merge_block(ssa_elimination_ctx& ctx, Block* block)
!(ctx.program->blocks[block->linear_succs[0]].kind & block_kind_merge))
return;
- /* check if this block is empty and the exec mask is not needed */
- for (aco_ptr<Instruction>& instr : block->instructions) {
- if (instr->opcode == aco_opcode::p_parallelcopy) {
- if (instr->definitions[0].physReg() == exec)
- continue;
- else
- return;
- }
-
- if (instr->opcode != aco_opcode::p_linear_phi &&
- instr->opcode != aco_opcode::p_phi &&
- instr->opcode != aco_opcode::p_logical_start &&
- instr->opcode != aco_opcode::p_logical_end &&
- instr->opcode != aco_opcode::p_branch)
- return;
- }
+ /* check if this block is empty */
+ if (!is_empty_block(block, true))
+ return;
/* keep the branch instruction and remove the rest */
aco_ptr<Instruction> branch = std::move(block->instructions.back());
@@ -146,18 +162,13 @@ void try_remove_merge_block(ssa_elimination_ctx& ctx, Block* block)
void try_remove_invert_block(ssa_elimination_ctx& ctx, Block* block)
{
assert(block->linear_succs.size() == 2);
+ /* only remove this block if the successor got removed as well */
if (block->linear_succs[0] != block->linear_succs[1])
return;
- /* check if we can remove this block */
- for (aco_ptr<Instruction>& instr : block->instructions) {
- if (instr->opcode != aco_opcode::p_linear_phi &&
- instr->opcode != aco_opcode::p_phi &&
- (instr->opcode != aco_opcode::s_andn2_b64 || ctx.program->wave_size != 64) &&
- (instr->opcode != aco_opcode::s_andn2_b32 || ctx.program->wave_size != 32) &&
- instr->opcode != aco_opcode::p_branch)
- return;
- }
+ /* check if block is otherwise empty */
+ if (!is_empty_block(block, true))
+ return;
unsigned succ_idx = block->linear_succs[0];
assert(block->linear_preds.size() == 2);
@@ -179,12 +190,8 @@ void try_remove_invert_block(ssa_elimination_ctx& ctx, Block* block)
void try_remove_simple_block(ssa_elimination_ctx& ctx, Block* block)
{
- for (aco_ptr<Instruction>& instr : block->instructions) {
- if (instr->opcode != aco_opcode::p_logical_start &&
- instr->opcode != aco_opcode::p_logical_end &&
- instr->opcode != aco_opcode::p_branch)
- return;
- }
+ if (!is_empty_block(block, false))
+ return;
Block& pred = ctx.program->blocks[block->linear_preds[0]];
Block& succ = ctx.program->blocks[block->linear_succs[0]];
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