src/freedreno/ir3/ir3_cf.c

   1 /*
   2  * Copyright (C) 2019 Google.
   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
  24 #include "ir3.h"
  25
  26 static bool
  27 is_fp16_conv(struct ir3_instruction *instr)
  28 {
  29         if (instr->opc == OPC_MOV &&
  30                         instr->cat1.src_type == TYPE_F32 &&
  31                         instr->cat1.dst_type == TYPE_F16)
  32                 return true;
  33
  34         return false;
  35 }
  36
  37 static bool
  38 all_uses_fp16_conv(struct ir3 *ir, struct ir3_instruction *conv_src)
  39 {
  40         foreach_block (block, &ir->block_list) {
  41                 foreach_instr (instr, &block->instr_list) {
  42                         struct ir3_instruction *src;
  43                         foreach_ssa_src (src, instr) {
  44                                 if (src == conv_src && !is_fp16_conv(instr))
  45                                         return false;
  46                         }
  47                 }
  48         }
  49
  50         return true;
  51 }
  52
  53 static void
  54 rewrite_uses(struct ir3 *ir, struct ir3_instruction *conv,
  55                          struct ir3_instruction *replace)
  56 {
  57         foreach_block (block, &ir->block_list) {
  58                 foreach_instr (instr, &block->instr_list) {
  59                         struct ir3_instruction *src;
  60                         foreach_ssa_src_n (src, n, instr) {
  61                                 if (src == conv)
  62                                         instr->regs[n]->instr = replace;
  63                         }
  64                 }
  65         }
  66 }
  67
  68 static void
  69 try_conversion_folding(struct ir3 *ir, struct ir3_instruction *conv)
  70 {
  71         struct ir3_instruction *src;
  72
  73         if (!is_fp16_conv(conv))
  74                 return;
  75
  76         src = ssa(conv->regs[1]);
  77         if (!is_alu(src))
  78                 return;
  79
  80         switch (src->opc) {
  81         case OPC_SEL_B32:
  82         case OPC_MAX_F:
  83         case OPC_MIN_F:
  84         case OPC_ABSNEG_F:
  85                 return;
  86         default:
  87                 break;
  88         }
  89
  90         if (!all_uses_fp16_conv(ir, src))
  91                 return;
  92
  93         if (src->opc == OPC_MOV) {
  94                 if (src->cat1.dst_type == src->cat1.src_type) {
  95                         /* If we're folding a conversion into a bitwise move, we need to
  96                          * change the dst type to F32 to get the right behavior, since we
  97                          * could be moving a float with a u32.u32 move.
  98                          */
  99                         src->cat1.dst_type = TYPE_F16;
 100                         src->cat1.src_type = TYPE_F32;
 101                 } else {
 102                         /* Otherwise, for typechanging movs, we can just change the dst
 103                          * type to F16 to collaps the two conversions.  For example
 104                          * cov.s32f32 follwed by cov.f32f16 becomes cov.s32f16.
 105                          */
 106                         src->cat1.dst_type = TYPE_F16;
 107                 }
 108         }
 109
 110         src->regs[0]->flags |= IR3_REG_HALF;
 111
 112         rewrite_uses(ir, conv, src);
 113 }
 114
 115 void
 116 ir3_cf(struct ir3 *ir)
 117 {
 118         foreach_block_safe (block, &ir->block_list) {
 119                 foreach_instr_safe (instr, &block->instr_list) {
 120                         try_conversion_folding(ir, instr);
 121                 }
 122         }
 123 }