From 9c328ea66ea0a85ac35704da1b50e7820297f709 Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Fri, 23 Aug 2019 16:14:13 -0700 Subject: [PATCH] pan/midgard: Add imov->fmov optimization MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When moving constants, if switching to a floating-point representation doesn't break anything, we'd rather have an fmov than an imov, permitting inlining the constant in many circumstances. total quadwords in shared programs: 3408 -> 3366 (-1.23%) quadwords in affected programs: 1188 -> 1146 (-3.54%) helped: 41 HURT: 0 helped stats (abs) min: 1 max: 2 x̄: 1.02 x̃: 1 helped stats (rel) min: 0.19% max: 25.00% x̄: 9.65% x̃: 11.11% 95% mean confidence interval for quadwords value: -1.07 -0.98 95% mean confidence interval for quadwords %-change: -11.38% -7.93% Quadwords are helped. Signed-off-by: Alyssa Rosenzweig --- src/panfrost/midgard/compiler.h | 1 + src/panfrost/midgard/meson.build | 1 + src/panfrost/midgard/midgard_compile.c | 1 + src/panfrost/midgard/midgard_opt_float.c | 82 ++++++++++++++++++++++++ 4 files changed, 85 insertions(+) create mode 100644 src/panfrost/midgard/midgard_opt_float.c diff --git a/src/panfrost/midgard/compiler.h b/src/panfrost/midgard/compiler.h index a64bb55203d..8bea56548ae 100644 --- a/src/panfrost/midgard/compiler.h +++ b/src/panfrost/midgard/compiler.h @@ -640,5 +640,6 @@ void midgard_lower_invert(compiler_context *ctx, midgard_block *block); bool midgard_opt_not_propagate(compiler_context *ctx, midgard_block *block); bool midgard_opt_fuse_src_invert(compiler_context *ctx, midgard_block *block); bool midgard_opt_fuse_dest_invert(compiler_context *ctx, midgard_block *block); +bool midgard_opt_promote_fmov(compiler_context *ctx, midgard_block *block); #endif diff --git a/src/panfrost/midgard/meson.build b/src/panfrost/midgard/meson.build index 8da5184e871..704d847cb4f 100644 --- a/src/panfrost/midgard/meson.build +++ b/src/panfrost/midgard/meson.build @@ -34,6 +34,7 @@ libpanfrost_midgard_files = files( 'midgard_opt_copy_prop.c', 'midgard_opt_dce.c', 'midgard_opt_invert.c', + 'midgard_opt_float.c', 'midgard_opt_perspective.c', 'cppwrap.cpp', 'disassemble.c', diff --git a/src/panfrost/midgard/midgard_compile.c b/src/panfrost/midgard/midgard_compile.c index be4318d371a..816adb7fd38 100644 --- a/src/panfrost/midgard/midgard_compile.c +++ b/src/panfrost/midgard/midgard_compile.c @@ -2305,6 +2305,7 @@ emit_block(compiler_context *ctx, nir_block *block) } inline_alu_constants(ctx); + midgard_opt_promote_fmov(ctx, ctx->current_block); embedded_to_inline_constant(ctx); /* Append fragment shader epilogue (value writeout) */ diff --git a/src/panfrost/midgard/midgard_opt_float.c b/src/panfrost/midgard/midgard_opt_float.c new file mode 100644 index 00000000000..630620120e3 --- /dev/null +++ b/src/panfrost/midgard/midgard_opt_float.c @@ -0,0 +1,82 @@ +/* + * Copyright (C) 2019 Collabora, Ltd. + * + * 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 (Collabora): + * Alyssa Rosenzweig + */ + +#include "compiler.h" +#include "midgard_ops.h" +#include + +/* Could a 32-bit value represent exactly a 32-bit floating point? */ + +static bool +mir_constant_float(uint32_t u) +{ + /* Cast */ + float f = 0; + memcpy(&f, &u, sizeof(u)); + + /* TODO: What exactly is the condition? */ + return !(isnan(f) || isinf(f)); +} + +/* Promotes imov with a constant to fmov where the constant is exactly + * representible as a float */ + +bool +midgard_opt_promote_fmov(compiler_context *ctx, midgard_block *block) +{ + bool progress = false; + + mir_foreach_instr_in_block(block, ins) { + if (ins->type != TAG_ALU_4) continue; + if (ins->alu.op != midgard_alu_op_imov) continue; + if (ins->ssa_args.inline_constant) continue; + if (!ins->has_constants) continue; + if (mir_nontrivial_source2_mod_simple(ins)) continue; + if (mir_nontrivial_outmod(ins)) continue; + + /* We found an imov with a constant. Check the constants */ + bool ok = true; + + for (unsigned i = 0; i < ARRAY_SIZE(ins->constants); ++i) + ok &= mir_constant_float(ins->constants[i]); + + if (!ok) + continue; + + /* Rewrite to fmov */ + ins->alu.op = midgard_alu_op_fmov; + ins->alu.outmod = 0; + + /* Clear the int mod */ + midgard_vector_alu_src u = vector_alu_from_unsigned(ins->alu.src2); + u.mod = 0; + ins->alu.src2 = vector_alu_srco_unsigned(u); + + progress |= true; + } + + return progress; +} -- 2.30.2