enc: always alloc tile data w/tile count change

Previously the code would retain an earlier allocation if the number of
tiles was less than or equal to the current count. This change always
reallocates tile data when the tile count changes. It avoids holding on
to extra memory unnecessarily. This is an uncommon condition, so there's
no need to optimize this.

Note this may be unnecessary after
  c2daa0f13c Use enc_row_mt->allocated_tile_cols/rows correctly
but given the complex logic around this code, forcing the allocation may
be safest.

Bug: 487259772
Change-Id: I6acd5febcd79dce89b59869bf65386df2c993dc8
(cherry picked from commit 900fa7eef8505fe0a530115c67c04d956e20f48e)

av1/encoder/encodeframe.c

diff --git a/av1/encoder/encodeframe.c b/av1/encoder/encodeframe.c
index 733f269..423f2f9 100644
--- a/av1/encoder/encodeframe.c
+++ b/av1/encoder/encodeframe.c
@@ -1556,9 +1556,8 @@
   int tile_col, tile_row;
 
   MACROBLOCK *const mb = &cpi->td.mb;
-  assert(IMPLIES(cpi->tile_data == NULL,
-                 cpi->allocated_tiles < tile_cols * tile_rows));
-  if (cpi->allocated_tiles < tile_cols * tile_rows) av1_alloc_tile_data(cpi);
+  assert(IMPLIES(cpi->tile_data == NULL, cpi->allocated_tiles == 0));
+  if (cpi->allocated_tiles != tile_cols * tile_rows) av1_alloc_tile_data(cpi);
 
   av1_init_tile_data(cpi);
   av1_alloc_mb_data(cpi, mb);

av1/encoder/ethread.c

diff --git a/av1/encoder/ethread.c b/av1/encoder/ethread.c
index 3b38c80..fb6a13a 100644
--- a/av1/encoder/ethread.c
+++ b/av1/encoder/ethread.c
@@ -249,6 +249,7 @@
   av1_row_mt_mem_dealloc(cpi);
 
   // Allocate memory for row based multi-threading
+  assert(cpi->allocated_tiles == tile_cols * tile_rows);
   for (tile_row = 0; tile_row < tile_rows; tile_row++) {
     for (tile_col = 0; tile_col < tile_cols; tile_col++) {
       int tile_index = tile_row * tile_cols + tile_col;
@@ -1736,9 +1737,8 @@
   const int tile_rows = cm->tiles.rows;
   int num_workers = mt_info->num_mod_workers[MOD_ENC];
 
-  assert(IMPLIES(cpi->tile_data == NULL,
-                 cpi->allocated_tiles < tile_cols * tile_rows));
-  if (cpi->allocated_tiles < tile_cols * tile_rows) av1_alloc_tile_data(cpi);
+  assert(IMPLIES(cpi->tile_data == NULL, cpi->allocated_tiles == 0));
+  if (cpi->allocated_tiles != tile_cols * tile_rows) av1_alloc_tile_data(cpi);
 
   av1_init_tile_data(cpi);
   num_workers = AOMMIN(num_workers, mt_info->num_workers);
@@ -1926,9 +1926,10 @@
        enc_row_mt->allocated_rows != max_sb_rows_in_tile ||
        enc_row_mt->allocated_cols != (max_sb_cols_in_tile - 1) ||
        enc_row_mt->allocated_sb_rows != sb_rows_in_frame);
-  const bool alloc_tile_data = cpi->allocated_tiles < tile_cols * tile_rows;
+  const bool alloc_tile_data = cpi->allocated_tiles != tile_cols * tile_rows;
 
   assert(IMPLIES(cpi->tile_data == NULL, alloc_tile_data));
+  assert(IMPLIES(cpi->tile_data == NULL, cpi->allocated_tiles == 0));
   if (alloc_tile_data) {
     av1_alloc_tile_data(cpi);
   }
@@ -2004,9 +2005,10 @@
   const bool alloc_row_mt_mem = enc_row_mt->allocated_tile_cols != tile_cols ||
                                 enc_row_mt->allocated_tile_rows != tile_rows ||
                                 enc_row_mt->allocated_rows != max_mb_rows;
-  const bool alloc_tile_data = cpi->allocated_tiles < tile_cols * tile_rows;
+  const bool alloc_tile_data = cpi->allocated_tiles != tile_cols * tile_rows;
 
   assert(IMPLIES(cpi->tile_data == NULL, alloc_tile_data));
+  assert(IMPLIES(cpi->tile_data == NULL, cpi->allocated_tiles == 0));
   if (alloc_tile_data) {
     av1_alloc_tile_data(cpi);
   }

av1/encoder/firstpass.c

diff --git a/av1/encoder/firstpass.c b/av1/encoder/firstpass.c
index 572ff0e..4436f00 100644
--- a/av1/encoder/firstpass.c
+++ b/av1/encoder/firstpass.c
@@ -1334,7 +1334,7 @@
 
   const int tile_cols = cm->tiles.cols;
   const int tile_rows = cm->tiles.rows;
-  if (cpi->allocated_tiles < tile_cols * tile_rows) {
+  if (cpi->allocated_tiles != tile_cols * tile_rows) {
     av1_alloc_tile_data(cpi);
   }