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aco: rework removal of jumps over branches

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Only allow this in situations where we know it's safe. In particular, this
stops removal of unconditional branches like with
block_kind_continue_or_break.

Fixes dEQP-VK.graphicsfuzz.fragcoord-control-flow hang.

fossil-db (Sienna Cichlid):
Totals from 34 (0.02% of 162293) affected shaders:
Instrs: 84115 -> 84178 (+0.07%); split: -0.00%, +0.08%
CodeSize: 463372 -> 463624 (+0.05%); split: -0.00%, +0.06%
Latency: 3467316 -> 3467652 (+0.01%)
InvThroughput: 3085493 -> 3085578 (+0.00%)
Branches: 3221 -> 3284 (+1.96%); split: -0.03%, +1.99%

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Fixes: f030b75b7d ("aco: relax condition to remove branches in case of few instructions")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15214>
This commit is contained in:
Rhys Perry
2022-03-02 13:32:42 +00:00
committed by Marge Bot
parent 059f870d74
commit d28b6b6856
1 changed files with 10 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/amd/compiler/aco_lower_to_hw_instr.cpp
+10 -13
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@@ -2207,7 +2207,6 @@ lower_to_hw_instr(Program* program)
bool can_remove = block->index < target;
unsigned num_scalar = 0;
unsigned num_vector = 0;
bool has_sopp = false;
/* Check the instructions between branch and target */
for (unsigned i = block->index + 1; i < branch->target[0]; i++) {
@@ -2221,19 +2220,17 @@ lower_to_hw_instr(Program* program)
for (aco_ptr<Instruction>& inst : program->blocks[i].instructions) {
if (inst->isSOPP()) {
/* we allow at most one inner branch */
if (has_sopp)
/* Discard early exits and loop breaks and continues should work fine with an
* empty exec mask.
*/
bool is_break_continue =
program->blocks[i].kind & (block_kind_break | block_kind_continue);
bool discard_early_exit =
discard_block && (unsigned)inst->sopp().block == discard_block->index;
if ((inst->opcode != aco_opcode::s_cbranch_scc0 &&
inst->opcode != aco_opcode::s_cbranch_scc1) ||
(!discard_early_exit && !is_break_continue))
can_remove = false;
/* These instructions must conditionally be jumped over */
if (inst->opcode == aco_opcode::s_endpgm ||
inst->opcode == aco_opcode::s_sendmsg ||
inst->opcode == aco_opcode::s_sendmsghalt ||
inst->opcode == aco_opcode::s_trap ||
inst->opcode == aco_opcode::s_barrier)
can_remove = false;
has_sopp = true;
} else if (inst->isSALU()) {
num_scalar++;
} else if (inst->isVALU() || inst->isVINTRP()) {