/*
 * 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 <alyssa.rosenzweig@collabora.com>
 */

#include "compiler.h"

/* When we're 'squeezing down' the values in the IR, we maintain a hash
 * as such */

static unsigned
find_or_allocate_temp(compiler_context *ctx, struct hash_table_u64 *map,
                      unsigned hash)
{
   if (hash >= SSA_FIXED_MINIMUM)
      return hash;

   unsigned temp = (uintptr_t)_mesa_hash_table_u64_search(map, hash + 1);

   if (temp)
      return temp - 1;

   /* If no temp is find, allocate one */
   temp = ctx->temp_count++;
   ctx->max_hash = MAX2(ctx->max_hash, hash);

   _mesa_hash_table_u64_insert(map, hash + 1, (void *)((uintptr_t)temp + 1));

   return temp;
}

/* Reassigns numbering to get rid of gaps in the indices and to prioritize
 * smaller register classes */

void
mir_squeeze_index(compiler_context *ctx)
{
   struct hash_table_u64 *map = _mesa_hash_table_u64_create(NULL);

   /* Reset */
   ctx->temp_count = 0;

   /* We need to prioritize texture registers on older GPUs so we don't
    * fail RA trying to assign to work registers r0/r1 when a work
    * register is already there */

   mir_foreach_instr_global(ctx, ins) {
      if (ins->type == TAG_TEXTURE_4)
         ins->dest = find_or_allocate_temp(ctx, map, ins->dest);
   }

   mir_foreach_instr_global(ctx, ins) {
      if (ins->type != TAG_TEXTURE_4)
         ins->dest = find_or_allocate_temp(ctx, map, ins->dest);

      for (unsigned i = 0; i < ARRAY_SIZE(ins->src); ++i)
         ins->src[i] = find_or_allocate_temp(ctx, map, ins->src[i]);
   }

   ctx->blend_input = find_or_allocate_temp(ctx, map, ctx->blend_input);
   ctx->blend_src1 = find_or_allocate_temp(ctx, map, ctx->blend_src1);

   _mesa_hash_table_u64_destroy(map);
}