From: Jason Ekstrand Date: Tue, 17 Mar 2015 18:29:01 +0000 (-0700) Subject: i965: Add a NIR analysis pass for determining when a boolean resolve is needed X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a55af2699feb8f64d6f480b223204da071606721;p=mesa.git i965: Add a NIR analysis pass for determining when a boolean resolve is needed v2: Fix the spelling of analyze and re-arrange code for better readability as per Connor's comments. v3: Make the naming of things more consistent and add a pile of comments v4: Stop trying to avoid vectors Reviewed-by: Matt Turner Reviewed-by: Connor Abbott --- diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources index c69441b5885..3a3df70ce83 100644 --- a/src/mesa/drivers/dri/i965/Makefile.sources +++ b/src/mesa/drivers/dri/i965/Makefile.sources @@ -73,6 +73,8 @@ i965_FILES = \ brw_meta_util.h \ brw_misc_state.c \ brw_multisample_state.h \ + brw_nir.h \ + brw_nir_analyze_boolean_resolves.c \ brw_object_purgeable.c \ brw_packed_float.c \ brw_performance_monitor.c \ diff --git a/src/mesa/drivers/dri/i965/brw_nir.h b/src/mesa/drivers/dri/i965/brw_nir.h new file mode 100644 index 00000000000..27782a3c807 --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_nir.h @@ -0,0 +1,78 @@ +/* + * Copyright © 2015 Intel Corporation + * + * 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. + */ + +#pragma once + +#include "glsl/nir/nir.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* Flags set in the instr->pass_flags field by i965 analysis passes */ +enum { + BRW_NIR_NON_BOOLEAN = 0x0, + + /* Indicates that the given instruction's destination is a boolean + * value but that it needs to be resolved before it can be used. + * On Gen <= 5, CMP instructions return a 32-bit value where the bottom + * bit represents the actual true/false value of the compare and the top + * 31 bits are undefined. In order to use this value, we have to do a + * "resolve" operation by replacing the value of the CMP with -(x & 1) + * to sign-extend the bottom bit to 0/~0. + */ + BRW_NIR_BOOLEAN_NEEDS_RESOLVE = 0x1, + + /* Indicates that the given instruction's destination is a boolean + * value that has intentionally been left unresolved. Not all boolean + * values need to be resolved immediately. For instance, if we have + * + * CMP r1 r2 r3 + * CMP r4 r5 r6 + * AND r7 r1 r4 + * + * We don't have to resolve the result of the two CMP instructions + * immediately because the AND still does an AND of the bottom bits. + * Instead, we can save ourselves instructions by delaying the resolve + * until after the AND. The result of the two CMP instructions is left + * as BRW_NIR_BOOLEAN_UNRESOLVED. + */ + BRW_NIR_BOOLEAN_UNRESOLVED = 0x2, + + /* Indicates a that the given instruction's destination is a boolean + * value that does not need a resolve. For instance, if you AND two + * values that are BRW_NIR_BOOLEAN_NEEDS_RESOLVE then we know that both + * values will be 0/~0 before we get them and the result of the AND is + * also guaranteed to be 0/~0 and does not need a resolve. + */ + BRW_NIR_BOOLEAN_NO_RESOLVE = 0x3, + + /* A mask to mask the boolean status values off of instr->pass_flags */ + BRW_NIR_BOOLEAN_MASK = 0x3, +}; + +void brw_nir_analyze_boolean_resolves(nir_shader *nir); + +#ifdef __cplusplus +} +#endif diff --git a/src/mesa/drivers/dri/i965/brw_nir_analyze_boolean_resolves.c b/src/mesa/drivers/dri/i965/brw_nir_analyze_boolean_resolves.c new file mode 100644 index 00000000000..3a27cf1a3d2 --- /dev/null +++ b/src/mesa/drivers/dri/i965/brw_nir_analyze_boolean_resolves.c @@ -0,0 +1,268 @@ +/* + * Copyright © 2015 Intel Corporation + * + * 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. + * + * Authors: + * Jason Ekstrand + */ + +#include "brw_nir.h" + +/* + * This file implements an analysis pass that determines when we have to do + * a boolean resolve on Gen <= 5. Instructions that need a boolean resolve + * will have the booleans portion of the instr->pass_flags field set to + * BRW_NIR_BOOLEAN_NEEDS_RESOLVE. + */ + + +/** Returns the resolve status for the given source + * + * If the source has a parent instruction then the resolve status is the + * status of the parent instruction. If the source does not have a parent + * instruction then we don't know so we return NON_BOOLEAN. + */ +static uint8_t +get_resolve_status_for_src(nir_src *src) +{ + nir_instr *src_instr; + if (src->is_ssa) { + src_instr = src->ssa->parent_instr; + } else { + src_instr = src->reg.reg->parent_instr; + } + + if (src_instr) { + uint8_t resolve_status = src_instr->pass_flags & BRW_NIR_BOOLEAN_MASK; + + /* If the source instruction needs resolve, then from the perspective + * of the user, it's a true boolean. + */ + if (resolve_status == BRW_NIR_BOOLEAN_NEEDS_RESOLVE) + resolve_status = BRW_NIR_BOOLEAN_NO_RESOLVE; + return resolve_status; + } else { + return BRW_NIR_NON_BOOLEAN; + } +} + +/** Marks the given source as needing a resolve + * + * If the given source corresponds to an unresolved boolean it marks it as + * needing a resolve. Otherwise, we leave it alone. + */ +static bool +src_mark_needs_resolve(nir_src *src, void *void_state) +{ + nir_instr *src_instr; + if (src->is_ssa) { + src_instr = src->ssa->parent_instr; + } else { + src_instr = src->reg.reg->parent_instr; + } + + if (src_instr) { + uint8_t resolve_status = src_instr->pass_flags & BRW_NIR_BOOLEAN_MASK; + + /* If the source instruction is unresolved, then mark it as needing + * to be resolved. + */ + if (resolve_status == BRW_NIR_BOOLEAN_UNRESOLVED) { + src_instr->pass_flags &= ~BRW_NIR_BOOLEAN_MASK; + src_instr->pass_flags |= BRW_NIR_BOOLEAN_NEEDS_RESOLVE; + } + + } + + return true; +} + +static bool +analyze_boolean_resolves_block(nir_block *block, void *void_state) +{ + nir_foreach_instr(block, instr) { + switch (instr->type) { + case nir_instr_type_alu: { + /* For ALU instructions, the resolve status is handled in a + * three-step process. + * + * 1) Look at the instruction type and sources and determine if it + * can be left unresolved. + * + * 2) Look at the destination and see if we have to resolve + * anyway. (This is the case if this instruction is not the + * only instruction writing to a given register.) + * + * 3) If the instruction has a resolve status other than + * BOOL_UNRESOLVED or BOOL_NEEDS_RESOLVE then we walk through + * the sources and ensure that they are also resolved. This + * ensures that we don't end up with any stray unresolved + * booleans going into ADDs or something like that. + */ + + uint8_t resolve_status; + nir_alu_instr *alu = nir_instr_as_alu(instr); + switch (alu->op) { + case nir_op_flt: + case nir_op_ilt: + case nir_op_ult: + case nir_op_fge: + case nir_op_ige: + case nir_op_uge: + case nir_op_feq: + case nir_op_ieq: + case nir_op_fne: + case nir_op_ine: + case nir_op_f2b: + case nir_op_i2b: + /* This instruction will turn into a CMP when we actually emit + * so the result will have to be resolved before it can be used. + */ + resolve_status = BRW_NIR_BOOLEAN_UNRESOLVED; + + /* Even though the destination is allowed to be left unresolved, + * the sources are treated as regular integers or floats so + * they need to be resolved. + */ + nir_foreach_src(instr, src_mark_needs_resolve, NULL); + break; + + case nir_op_imov: + case nir_op_inot: + /* This is a single-source instruction. Just copy the resolve + * status from the source. + */ + resolve_status = get_resolve_status_for_src(&alu->src[0].src); + break; + + case nir_op_iand: + case nir_op_ior: + case nir_op_ixor: { + uint8_t src0_status = get_resolve_status_for_src(&alu->src[0].src); + uint8_t src1_status = get_resolve_status_for_src(&alu->src[1].src); + + if (src0_status == src1_status) { + resolve_status = src0_status; + } else if (src0_status == BRW_NIR_NON_BOOLEAN || + src1_status == BRW_NIR_NON_BOOLEAN) { + /* If one of the sources is a non-boolean then the whole + * thing is a non-boolean. + */ + resolve_status = BRW_NIR_NON_BOOLEAN; + } else { + /* At this point one of them is a true boolean and one is a + * boolean that needs a resolve. We could either resolve the + * unresolved source or we could resolve here. If we resolve + * the unresolved source then we get two resolves for the price + * of one. Just set this one to BOOLEAN_NO_RESOLVE and we'll + * let the code below force a resolve on the unresolved source. + */ + resolve_status = BRW_NIR_BOOLEAN_NO_RESOLVE; + } + break; + } + + default: + resolve_status = BRW_NIR_NON_BOOLEAN; + } + + /* If the destination is SSA-like, go ahead allow unresolved booleans. + * If the destination register doesn't have a well-defined parent_instr + * we need to resolve immediately. + */ + if (alu->dest.dest.reg.reg->parent_instr == NULL && + resolve_status == BRW_NIR_BOOLEAN_UNRESOLVED) { + resolve_status = BRW_NIR_BOOLEAN_NEEDS_RESOLVE; + } + + instr->pass_flags = (instr->pass_flags & ~BRW_NIR_BOOLEAN_MASK) | + resolve_status; + + /* Finally, resolve sources if it's needed */ + switch (resolve_status) { + case BRW_NIR_BOOLEAN_NEEDS_RESOLVE: + case BRW_NIR_BOOLEAN_UNRESOLVED: + /* This instruction is either unresolved or we're doing the + * resolve here; leave the sources alone. + */ + break; + + case BRW_NIR_BOOLEAN_NO_RESOLVE: + case BRW_NIR_NON_BOOLEAN: + nir_foreach_src(instr, src_mark_needs_resolve, NULL); + break; + + default: + unreachable("Invalid boolean flag"); + } + + break; + } + + case nir_instr_type_load_const: { + nir_load_const_instr *load = nir_instr_as_load_const(instr); + + /* For load_const instructions, it's a boolean exactly when it holds + * one of the values NIR_TRUE or NIR_FALSE. + * + * Since load_const instructions don't have any sources, we don't + * have to worry about resolving them. + */ + instr->pass_flags &= ~BRW_NIR_BOOLEAN_MASK; + if (load->value.u[0] == NIR_TRUE || load->value.u[0] == NIR_FALSE) { + instr->pass_flags |= BRW_NIR_BOOLEAN_NO_RESOLVE; + } else { + instr->pass_flags |= BRW_NIR_NON_BOOLEAN; + } + continue; + } + + default: + /* Everything else is an unknown non-boolean value and needs to + * have all sources resolved. + */ + instr->pass_flags = (instr->pass_flags & ~BRW_NIR_BOOLEAN_MASK) | + BRW_NIR_NON_BOOLEAN; + nir_foreach_src(instr, src_mark_needs_resolve, NULL); + continue; + } + } + + nir_if *following_if = nir_block_get_following_if(block); + if (following_if) + src_mark_needs_resolve(&following_if->condition, NULL); + + return true; +} + +static void +analyze_boolean_resolves_impl(nir_function_impl *impl) +{ + nir_foreach_block(impl, analyze_boolean_resolves_block, NULL); +} + +void +brw_nir_analyze_boolean_resolves(nir_shader *shader) +{ + nir_foreach_overload(shader, overload) + if (overload->impl) + analyze_boolean_resolves_impl(overload->impl); +}