<div dir="ltr"><div class="gmail_quote"><div dir="ltr">On Tue, Jan 15, 2019 at 7:54 AM Iago Toral Quiroga <<a href="mailto:itoral@igalia.com">itoral@igalia.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Some conversions are not directly supported in hardware and need to be split in two conversion instructions going through an intermediary type. Doing this at the NIR level simplifies a bit the complexity in the backend. v2: - Consider fp16 rounding conversion opcodes - Properly handle swizzles on conversion sources. Reviewed-by: Topi Pohjolainen <<a href="mailto:topi.pohjolainen@intel.com" target="_blank">topi.pohjolainen@intel.com</a>> (v1) --- src/intel/Makefile.sources | 1 + src/intel/compiler/brw_nir.c | 1 + src/intel/compiler/brw_nir.h | 2 + .../compiler/brw_nir_lower_conversions.c | 158 ++++++++++++++++++ src/intel/compiler/meson.build | 1 + 5 files changed, 163 insertions(+) create mode 100644 src/intel/compiler/brw_nir_lower_conversions.c diff --git a/src/intel/Makefile.sources b/src/intel/Makefile.sources index 94a28d370e8..9975daa3ad1 100644 --- a/src/intel/Makefile.sources +++ b/src/intel/Makefile.sources @@ -83,6 +83,7 @@ COMPILER_FILES = \ compiler/brw_nir_analyze_boolean_resolves.c \ compiler/brw_nir_analyze_ubo_ranges.c \ compiler/brw_nir_attribute_workarounds.c \ + compiler/brw_nir_lower_conversions.c \ compiler/brw_nir_lower_cs_intrinsics.c \ compiler/brw_nir_lower_image_load_store.c \ compiler/brw_nir_lower_mem_access_bit_sizes.c \ diff --git a/src/intel/compiler/brw_nir.c b/src/intel/compiler/brw_nir.c index 92d7fe4bede..572ab824a94 100644 --- a/src/intel/compiler/brw_nir.c +++ b/src/intel/compiler/brw_nir.c @@ -882,6 +882,7 @@ brw_postprocess_nir(nir_shader *nir, const struct brw_compiler *compiler, OPT(nir_opt_move_comparisons); OPT(nir_lower_bool_to_int32); + OPT(brw_nir_lower_conversions); </blockquote><div> </div><div>This is *really* late and I don't think you actually want this to run after we apply source/destination modifiers. If you just move it to right after nir_opt_algebraic_late, that will fix a multitude of issues. </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> OPT(nir_lower_locals_to_regs); diff --git a/src/intel/compiler/brw_nir.h b/src/intel/compiler/brw_nir.h index bc81950d47e..662b2627e95 100644 --- a/src/intel/compiler/brw_nir.h +++ b/src/intel/compiler/brw_nir.h @@ -114,6 +114,8 @@ void brw_nir_lower_tcs_outputs(nir_shader *nir, const struct brw_vue_map *vue, GLenum tes_primitive_mode); void brw_nir_lower_fs_outputs(nir_shader *nir); +bool brw_nir_lower_conversions(nir_shader *nir); + bool brw_nir_lower_image_load_store(nir_shader *nir, const struct gen_device_info *devinfo); void brw_nir_rewrite_image_intrinsic(nir_intrinsic_instr *intrin, diff --git a/src/intel/compiler/brw_nir_lower_conversions.c b/src/intel/compiler/brw_nir_lower_conversions.c new file mode 100644 index 00000000000..583167c7753 --- /dev/null +++ b/src/intel/compiler/brw_nir_lower_conversions.c @@ -0,0 +1,158 @@ +/* + * Copyright © 2018 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. + */ + +#include "brw_nir.h" +#include "compiler/nir/nir_builder.h" + +static nir_op +get_conversion_op(nir_alu_type src_type, + unsigned src_bit_size, + nir_alu_type dst_type, + unsigned dst_bit_size, + nir_rounding_mode rounding_mode) +{ + nir_alu_type src_full_type = (nir_alu_type) (src_type | src_bit_size); + nir_alu_type dst_full_type = (nir_alu_type) (dst_type | dst_bit_size); + + return nir_type_conversion_op(src_full_type, dst_full_type, rounding_mode); +} + +static nir_rounding_mode +get_opcode_rounding_mode(nir_op op) +{ + switch (op) { + case nir_op_f2f16_rtz: + return nir_rounding_mode_rtz; + case nir_op_f2f16_rtne: + return nir_rounding_mode_rtne; + default: + return nir_rounding_mode_undef; + } +} + +static void +split_conversion(nir_builder *b, nir_alu_instr *alu, nir_op op1, nir_op op2) +{ + b->cursor = nir_before_instr(&alu->instr); + assert(alu->dest.write_mask == 1); + nir_ssa_def *src = nir_ssa_for_alu_src(b, alu, 0); </blockquote><div> </div>Hrm... Given how late this pass runs, I'm not a fan of using nir_ssa_for_alu_src because it might insert a MOV and we don't copy-prop afterwards. Instead, we could assert that the destination is SSA and do</div><div class="gmail_quote"> </div><div class="gmail_quote">b->cursor = nir_after_instr(&alu->instr);</div><div class="gmail_quote">alu->op = op1;</div><div class="gmail_quote">alu->dest.bit_size = nir_alu_type_get_type_size(nir_op_infos[alu->op].output_type); </div><div class="gmail_quote">nir_ssa_def *new_res = nir_build_alu(b, op2, &alu->dest.dest.ssa, NULL, NULL, NULL);</div><div class="gmail_quote">nir_ssa_def_rewrite_uses_after(&alu->dest.dest.ssa, nir_src_for_ssa(new_res),</div><div class="gmail_quote"> new_res->parent_instr);</div><div class="gmail_quote"> </div><div class="gmail_quote">If you don't feel comfortable whacking the opcode in the original instruction, then just make a new one and build it directly with the old instruction's ALU src. Or, we could just move where it's run. (see my comment above.) </div><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + nir_ssa_def *tmp = nir_build_alu(b, op1, src, NULL, NULL, NULL); + nir_ssa_def *res = nir_build_alu(b, op2, tmp, NULL, NULL, NULL); + nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa, nir_src_for_ssa(res)); + nir_instr_remove(&alu->instr); +} + +static bool +lower_instr(nir_builder *b, nir_alu_instr *alu) +{ + unsigned src_bit_size = nir_src_bit_size(alu->src[0].src); + nir_alu_type src_type = nir_op_infos[alu->op].input_types[0]; + nir_alu_type src_full_type = (nir_alu_type) (src_type | src_bit_size); + + unsigned dst_bit_size = nir_dest_bit_size(alu->dest.dest); + nir_alu_type dst_type = nir_op_infos[alu->op].output_type; </blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + nir_alu_type dst_full_type = (nir_alu_type) (dst_type | dst_bit_size); </blockquote><div> </div><div>The nir_op_infos[*].output_type will already be a full type. Maybe just delete the dst_type temporary so that no one gets confused and thinks it's a base type. </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + + /* BDW PRM, vol02, Command Reference Instructions, mov - MOVE: + * + * "There is no direct conversion from HF to DF or DF to HF. + * Use two instructions and F (Float) as an intermediate type. + * + * There is no direct conversion from HF to Q/UQ or Q/UQ to HF. + * Use two instructions and F (Float) or a word integer type + * or a DWord integer type as an intermediate type." + */ + if ((src_full_type == nir_type_float16 && dst_bit_size == 64) || + (src_bit_size == 64 && dst_full_type == nir_type_float16)) { + nir_op op1 = get_conversion_op(src_type, src_bit_size, src_type, 32, + nir_rounding_mode_undef); + nir_op op2 = get_conversion_op(src_type, 32, dst_type, dst_bit_size, + get_opcode_rounding_mode(alu->op)); + split_conversion(b, alu, op1, op2); + return true; + } + + /* SKL PRM, vol 02a, Command Reference: Instructions, Move: + * + * "There is no direct conversion from B/UB to DF or DF to B/UB. Use + * two instructions and a word or DWord intermediate type." + * + * "There is no direct conversion from B/UB to Q/UQ or Q/UQ to B/UB. + * Use two instructions and a word or DWord intermediate integer + * type." + */ + if ((src_bit_size == 8 && dst_bit_size == 64) || + (src_bit_size == 64 && dst_bit_size == 8)) { + nir_op op1 = get_conversion_op(src_type, src_bit_size, src_type, 32, + nir_rounding_mode_undef); + nir_op op2 = get_conversion_op(src_type, 32, dst_type, dst_bit_size, + nir_rounding_mode_undef); + split_conversion(b, alu, op1, op2); + return true; + } + + return false; +} + +static bool +lower_impl(nir_function_impl *impl) +{ + nir_builder b; + nir_builder_init(&b, impl); + bool progress = false; + + nir_foreach_block(block, impl) { + nir_foreach_instr_safe(instr, block) { + if (instr->type != nir_instr_type_alu) + continue; + + nir_alu_instr *alu = nir_instr_as_alu(instr); + assert(alu->dest.dest.is_ssa); + + if (nir_op_infos[alu->op].num_inputs > 1) </blockquote><div> </div><div>I don't think this is a reliable way to detect conversion opcodes. There are many unary operations that aren't conversions. You're only getting lucky because there are non which do float16 <-> 64=bit or 8-bit <-> 64-bit. I've thought many times about throwing a boolean in nir_op_infos for is_conversion. Maybe now is a good time to do it? </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + continue; + + progress = lower_instr(&b, alu) || progress; + } + } + + if (progress) { + nir_metadata_preserve(impl, nir_metadata_block_index | + nir_metadata_dominance); + } + + return progress; +} + +bool +brw_nir_lower_conversions(nir_shader *shader) +{ + bool progress = false; + + nir_foreach_function(function, shader) { + if (function->impl) + progress |= lower_impl(function->impl); + } + + return progress; +} diff --git a/src/intel/compiler/meson.build b/src/intel/compiler/meson.build index f8e5e2518fe..9daf2a94260 100644 --- a/src/intel/compiler/meson.build +++ b/src/intel/compiler/meson.build @@ -76,6 +76,7 @@ libintel_compiler_files = files( 'brw_nir_analyze_boolean_resolves.c', 'brw_nir_analyze_ubo_ranges.c', 'brw_nir_attribute_workarounds.c', + 'brw_nir_lower_conversions.c', 'brw_nir_lower_cs_intrinsics.c', 'brw_nir_lower_image_load_store.c', 'brw_nir_lower_mem_access_bit_sizes.c', -- 2.17.1 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div></div>