/* * Copyright © 2014 Broadcom * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ /** * @file vc4_opt_algebraic.c * * This is the optimization pass for miscellaneous changes to instructions * where we can simplify the operation by some knowledge about the specific * operations. * * Mostly this will be a matter of turning things into MOVs so that they can * later be copy-propagated out. */ #include "vc4_qir.h" #include "util/u_math.h" static bool debug; static void dump_from(struct vc4_compile *c, struct qinst *inst) { if (!debug) return; fprintf(stderr, "optimizing: "); qir_dump_inst(c, inst); fprintf(stderr, "\n"); } static void dump_to(struct vc4_compile *c, struct qinst *inst) { if (!debug) return; fprintf(stderr, "to: "); qir_dump_inst(c, inst); fprintf(stderr, "\n"); } static struct qreg follow_movs(struct qinst **defs, struct qreg reg) { while (reg.file == QFILE_TEMP && defs[reg.index]->op == QOP_MOV) reg = defs[reg.index]->src[0]; return reg; } static bool is_zero(struct vc4_compile *c, struct qinst **defs, struct qreg reg) { reg = follow_movs(defs, reg); return (reg.file == QFILE_UNIF && c->uniform_contents[reg.index] == QUNIFORM_CONSTANT && c->uniform_data[reg.index] == 0); } static bool is_1f(struct vc4_compile *c, struct qinst **defs, struct qreg reg) { reg = follow_movs(defs, reg); return (reg.file == QFILE_UNIF && c->uniform_contents[reg.index] == QUNIFORM_CONSTANT && c->uniform_data[reg.index] == fui(1.0)); } static void replace_with_mov(struct vc4_compile *c, struct qinst *inst, struct qreg arg) { dump_from(c, inst); inst->op = QOP_MOV; inst->src[0] = arg; inst->src[1] = c->undef; dump_to(c, inst); } static bool add_replace_zero(struct vc4_compile *c, struct qinst **defs, struct qinst *inst, int arg) { if (!is_zero(c, defs, inst->src[arg])) return false; replace_with_mov(c, inst, inst->src[1 - arg]); return true; } static bool fmul_replace_zero(struct vc4_compile *c, struct qinst **defs, struct qinst *inst, int arg) { if (!is_zero(c, defs, inst->src[arg])) return false; replace_with_mov(c, inst, inst->src[arg]); return true; } static bool fmul_replace_one(struct vc4_compile *c, struct qinst **defs, struct qinst *inst, int arg) { if (!is_1f(c, defs, inst->src[arg])) return false; replace_with_mov(c, inst, inst->src[1 - arg]); return true; } bool qir_opt_algebraic(struct vc4_compile *c) { bool progress = false; struct simple_node *node; struct qinst *defs[c->num_temps]; foreach(node, &c->instructions) { struct qinst *inst = (struct qinst *)node; if (inst->dst.file == QFILE_TEMP) defs[inst->dst.index] = inst; switch (inst->op) { case QOP_SF: /* SF just looks at the sign bit, or whether all the * bits are 0. This is preserved across an itof * transformation. */ if (inst->src[0].file == QFILE_TEMP && defs[inst->src[0].index]->op == QOP_ITOF) { dump_from(c, inst); inst->src[0] = defs[inst->src[0].index]->src[0]; progress = true; dump_to(c, inst); break; } break; case QOP_SEL_X_Y_ZS: case QOP_SEL_X_Y_ZC: case QOP_SEL_X_Y_NS: case QOP_SEL_X_Y_NC: if (qir_reg_equals(inst->src[0], inst->src[1])) { /* Turn "dst = (sf == x) ? a : a)" into * "dst = a" */ replace_with_mov(c, inst, inst->src[1]); progress = true; break; } if (is_zero(c, defs, inst->src[1])) { /* Replace references to a 0 uniform value * with the SEL_X_0 equivalent. */ dump_from(c, inst); inst->op -= (QOP_SEL_X_Y_ZS - QOP_SEL_X_0_ZS); inst->src[1] = c->undef; progress = true; dump_to(c, inst); break; } if (is_zero(c, defs, inst->src[0])) { /* Replace references to a 0 uniform value * with the SEL_X_0 equivalent, flipping the * condition being evaluated since the operand * order is flipped. */ dump_from(c, inst); inst->op -= QOP_SEL_X_Y_ZS; inst->op ^= 1; inst->op += QOP_SEL_X_0_ZS; inst->src[0] = inst->src[1]; inst->src[1] = c->undef; progress = true; dump_to(c, inst); break; } break; case QOP_FSUB: case QOP_SUB: if (is_zero(c, defs, inst->src[1])) { replace_with_mov(c, inst, inst->src[0]); } break; case QOP_ADD: if (add_replace_zero(c, defs, inst, 0) || add_replace_zero(c, defs, inst, 1)) { progress = true; break; } break; case QOP_FADD: if (add_replace_zero(c, defs, inst, 0) || add_replace_zero(c, defs, inst, 1)) { progress = true; break; } /* FADD(a, FSUB(0, b)) -> FSUB(a, b) */ if (inst->src[1].file == QFILE_TEMP && defs[inst->src[1].index]->op == QOP_FSUB) { struct qinst *fsub = defs[inst->src[1].index]; if (is_zero(c, defs, fsub->src[0])) { dump_from(c, inst); inst->op = QOP_FSUB; inst->src[1] = fsub->src[1]; progress = true; dump_to(c, inst); break; } } /* FADD(FSUB(0, b), a) -> FSUB(a, b) */ if (inst->src[0].file == QFILE_TEMP && defs[inst->src[0].index]->op == QOP_FSUB) { struct qinst *fsub = defs[inst->src[0].index]; if (is_zero(c, defs, fsub->src[0])) { dump_from(c, inst); inst->op = QOP_FSUB; inst->src[0] = inst->src[1]; inst->src[1] = fsub->src[1]; dump_to(c, inst); progress = true; break; } } break; case QOP_FMUL: if (fmul_replace_zero(c, defs, inst, 0) || fmul_replace_zero(c, defs, inst, 1) || fmul_replace_one(c, defs, inst, 0) || fmul_replace_one(c, defs, inst, 1)) { progress = true; break; } break; default: break; } } return progress; }