src/panfrost/midgard/midgard_opt_float.c

   1 /*
   2  * Copyright (C) 2019 Collabora, Ltd.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  *
  23  * Authors (Collabora):
  24  *    Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
  25  */
  26
  27 #include "compiler.h"
  28 #include "midgard_ops.h"
  29 #include <math.h>
  30
  31 /* Could a 32-bit value represent exactly a 32-bit floating point? */
  32
  33 static bool
  34 mir_constant_float(uint32_t u)
  35 {
  36         /* Cast */
  37         float f = 0;
  38         memcpy(&f, &u, sizeof(u));
  39
  40         /* TODO: What exactly is the condition? */
  41         return !(isnan(f) || isinf(f));
  42 }
  43
  44 /* Promotes imov with a constant to fmov where the constant is exactly
  45  * representible as a float */
  46
  47 bool
  48 midgard_opt_promote_fmov(compiler_context *ctx, midgard_block *block)
  49 {
  50         bool progress = false;
  51
  52         mir_foreach_instr_in_block(block, ins) {
  53                 if (ins->type != TAG_ALU_4) continue;
  54                 if (ins->alu.op != midgard_alu_op_imov) continue;
  55                 if (ins->has_inline_constant) continue;
  56                 if (!ins->has_constants) continue;
  57                 if (mir_nontrivial_source2_mod_simple(ins)) continue;
  58                 if (mir_nontrivial_outmod(ins)) continue;
  59                 if (ins->alu.reg_mode != midgard_reg_mode_32) continue;
  60
  61                 /* We found an imov with a constant. Check the constants */
  62                 bool ok = true;
  63
  64                 for (unsigned i = 0; i < ARRAY_SIZE(ins->constants.u32); ++i)
  65                         ok &= mir_constant_float(ins->constants.u32[i]);
  66
  67                 if (!ok)
  68                         continue;
  69
  70                 /* Rewrite to fmov */
  71                 ins->alu.op = midgard_alu_op_fmov;
  72                 ins->alu.outmod = 0;
  73
  74                 /* Clear the int mod */
  75                 midgard_vector_alu_src u = vector_alu_from_unsigned(ins->alu.src2);
  76                 u.mod = 0;
  77                 ins->alu.src2 = vector_alu_srco_unsigned(u);
  78
  79                 progress |= true;
  80         }
  81
  82         return progress;
  83 }