diff options
| -rw-r--r-- | src/broadcom/compiler/vir_opt_dead_code.c | 46 |
1 files changed, 42 insertions, 4 deletions
diff --git a/src/broadcom/compiler/vir_opt_dead_code.c b/src/broadcom/compiler/vir_opt_dead_code.c index 9c93846e9b8..a486708bfa5 100644 --- a/src/broadcom/compiler/vir_opt_dead_code.c +++ b/src/broadcom/compiler/vir_opt_dead_code.c @@ -92,6 +92,24 @@ can_write_to_null(struct v3d_compile *c, struct qinst *inst) return true; } +static void +vir_dce_flags(struct v3d_compile *c, struct qinst *inst) +{ + if (debug) { + fprintf(stderr, + "Removing flags write from: "); + vir_dump_inst(c, inst); + fprintf(stderr, "\n"); + } + + assert(inst->qpu.type == V3D_QPU_INSTR_TYPE_ALU); + + inst->qpu.flags.apf = V3D_QPU_PF_NONE; + inst->qpu.flags.mpf = V3D_QPU_PF_NONE; + inst->qpu.flags.auf = V3D_QPU_UF_NONE; + inst->qpu.flags.muf = V3D_QPU_UF_NONE; +} + bool vir_opt_dead_code(struct v3d_compile *c) { @@ -112,7 +130,15 @@ vir_opt_dead_code(struct v3d_compile *c) } vir_for_each_block(block, c) { + struct qinst *last_flags_write = NULL; + vir_for_each_inst_safe(inst, block) { + /* If this instruction reads the flags, we can't + * remove the flags generation for it. + */ + if (v3d_qpu_reads_flags(&inst->qpu)) + last_flags_write = NULL; + if (inst->dst.file != QFILE_NULL && !(inst->dst.file == QFILE_TEMP && !used[inst->dst.index])) { @@ -122,10 +148,21 @@ vir_opt_dead_code(struct v3d_compile *c) if (vir_has_side_effects(c, inst)) continue; - if (inst->qpu.flags.apf != V3D_QPU_PF_NONE || - inst->qpu.flags.mpf != V3D_QPU_PF_NONE || - inst->qpu.flags.auf != V3D_QPU_UF_NONE || - inst->qpu.flags.muf != V3D_QPU_UF_NONE || + if (v3d_qpu_writes_flags(&inst->qpu)) { + /* If we obscure a previous flags write, + * drop it. + */ + if (last_flags_write && + (inst->qpu.flags.apf != V3D_QPU_PF_NONE || + inst->qpu.flags.mpf != V3D_QPU_PF_NONE)) { + vir_dce_flags(c, last_flags_write); + progress = true; + } + + last_flags_write = inst; + } + + if (v3d_qpu_writes_flags(&inst->qpu) || has_nonremovable_reads(c, inst)) { /* If we can't remove the instruction, but we * don't need its destination value, just @@ -162,6 +199,7 @@ vir_opt_dead_code(struct v3d_compile *c) } } + assert(inst != last_flags_write); dce(c, inst); progress = true; continue; |