llvmpipe: shortcircuit repeated lookups of the same tile

The lp_tile_cache is often called repeatedly to look up the same
tile.  Add a cache (to the cache) of the single tile most recently
retreived and make a quick inline check to see if this matches the
subsequent request.

Add a tile_address bitfield struct to make this check easier.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/gallium/drivers/llvmpipe/lp_tex_sample.c b/src/gallium/drivers/llvmpipe/lp_tex_sample.c
index 5a11ba0175..d24845cac9 100644
--- a/src/gallium/drivers/llvmpipe/lp_tex_sample.c
+++ b/src/gallium/drivers/llvmpipe/lp_tex_sample.c
@@ -680,11 +680,13 @@ get_texel(const struct tgsi_sampler *tgsi_sampler,
       rgba[3][j] = sampler->border_color[3];
    }
    else {
-      const int tx = x % TILE_SIZE;
-      const int ty = y % TILE_SIZE;
-      const struct llvmpipe_cached_tile *tile
-         = lp_get_cached_tile_tex(samp->cache,
-                                  x, y, z, face, level);
+      const unsigned tx = x % TILE_SIZE;
+      const unsigned ty = y % TILE_SIZE;
+      const struct llvmpipe_cached_tile *tile;
+
+      tile = lp_get_cached_tile_tex(samp->cache, 
+                                    tile_address(x, y, z, face, level));
+
       rgba[0][j] = tile->data.color[ty][tx][0];
       rgba[1][j] = tile->data.color[ty][tx][1];
       rgba[2][j] = tile->data.color[ty][tx][2];