From 38b7f411a1fb26ef4b2714852c7f950f0a3a710c Mon Sep 17 00:00:00 2001 From: Iago Toral Quiroga Date: Wed, 26 Jun 2024 08:06:33 +0200 Subject: [PATCH] broadcom/compiler: don't spill in between multop and umul24 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The multop instruction implicitly writes rtop which is not preserved acrosss thread switches. We can spill the sources of the multop (since these would happen before multop) and the destination of umul24 (since that would happen after umul24). Fixes some OpenCL tests when V3D_DEBUG=opt_compile_time is used to choose a different compile configuration. cc: mesa-stable Reviewed-by: Alejandro Piñeiro Part-of: --- src/broadcom/compiler/vir_register_allocate.c | 22 +++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/src/broadcom/compiler/vir_register_allocate.c b/src/broadcom/compiler/vir_register_allocate.c index 54c3da72baf..4fdf134a2ed 100644 --- a/src/broadcom/compiler/vir_register_allocate.c +++ b/src/broadcom/compiler/vir_register_allocate.c @@ -271,6 +271,7 @@ v3d_choose_spill_node(struct v3d_compile *c) float block_scale = 1.0; float spill_costs[c->num_temps]; bool in_tmu_operation = false; + bool rtop_hazard = false; bool started_last_seg = false; for (unsigned i = 0; i < c->num_temps; i++) @@ -279,6 +280,20 @@ v3d_choose_spill_node(struct v3d_compile *c) /* XXX: Scale the cost up when inside of a loop. */ vir_for_each_block(block, c) { vir_for_each_inst(inst, block) { + /* RTOP is not preserved across thread switches, so + * we can't spill in the middle of multop + umul24. + */ + bool is_multop = false; + bool is_umul24 = false; + if (inst->qpu.type == V3D_QPU_INSTR_TYPE_ALU) { + if (inst->qpu.alu.mul.op == V3D_QPU_M_MULTOP) { + is_multop = true; + rtop_hazard = true; + } else if (inst->qpu.alu.mul.op == V3D_QPU_M_UMUL24) { + is_umul24 = true; + } + } + /* We can't insert new thread switches after * starting output writes. */ @@ -297,7 +312,7 @@ v3d_choose_spill_node(struct v3d_compile *c) if (spill_type != SPILL_TYPE_TMU) { spill_costs[temp] += block_scale; - } else if (!no_spilling) { + } else if (!no_spilling && (!rtop_hazard || is_multop)) { float tmu_op_scale = in_tmu_operation ? 3.0 : 1.0; spill_costs[temp] += (block_scale * @@ -315,7 +330,7 @@ v3d_choose_spill_node(struct v3d_compile *c) if (spill_type != SPILL_TYPE_TMU) { /* We just rematerialize it later */ - } else if (!no_spilling) { + } else if (!no_spilling && (!rtop_hazard || is_umul24)) { spill_costs[temp] += (block_scale * tmu_scale); } else { @@ -344,6 +359,9 @@ v3d_choose_spill_node(struct v3d_compile *c) if (qinst_writes_tmu(c->devinfo, inst)) in_tmu_operation = true; + + if (is_umul24) + rtop_hazard = false; } }