From 34ff50cadd8157c5f41db301aa26d42af4c708b2 Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Sat, 28 Sep 2019 10:22:35 -0400 Subject: [PATCH] pan/midgard: Only one conditional per bundle allowed There's no r32 to save ya after you use up r31 :) Signed-off-by: Alyssa Rosenzweig --- src/panfrost/midgard/midgard_schedule.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/src/panfrost/midgard/midgard_schedule.c b/src/panfrost/midgard/midgard_schedule.c index ddd5edd7c84..ff71e0dcd3f 100644 --- a/src/panfrost/midgard/midgard_schedule.c +++ b/src/panfrost/midgard/midgard_schedule.c @@ -335,6 +335,10 @@ struct midgard_predicate { /* Exclude this destination (if not ~0) */ unsigned exclude; + + /* Don't schedule instructions consuming conditionals (since we already + * scheduled one). Excludes conditional branches and csel */ + bool no_cond; }; /* For an instruction that can fit, adjust it to fit and update the constants @@ -394,12 +398,14 @@ mir_choose_instruction( unsigned unit = predicate->unit; bool branch = alu && (unit == ALU_ENAB_BR_COMPACT); bool scalar = (unit != ~0) && (unit & UNITS_SCALAR); + bool no_cond = predicate->no_cond; /* Iterate to find the best instruction satisfying the predicate */ unsigned i; BITSET_WORD tmp; signed best_index = -1; + bool best_conditional = false; /* Enforce a simple metric limiting distance to keep down register * pressure. TOOD: replace with liveness tracking for much better @@ -434,11 +440,18 @@ mir_choose_instruction( if (alu && !mir_adjust_constants(instructions[i], predicate, false)) continue; + bool conditional = alu && !branch && OP_IS_CSEL(instructions[i]->alu.op); + conditional |= (branch && !instructions[i]->prepacked_branch && instructions[i]->branch.conditional); + + if (conditional && no_cond) + continue; + /* Simulate in-order scheduling */ if ((signed) i < best_index) continue; best_index = i; + best_conditional = conditional; } @@ -455,6 +468,9 @@ mir_choose_instruction( if (alu) mir_adjust_constants(instructions[best_index], predicate, true); + + /* Once we schedule a conditional, we can't again */ + predicate->no_cond |= best_conditional; } return instructions[best_index]; -- 2.30.2