Faster x264_macroblock_encode_pskip

GCC is apparently unable to optimize out the calculation of a variable when it isn't used.

diff --git a/encoder/macroblock.c b/encoder/macroblock.c
index 789aa48305228114e90b90f0bc1ae4df5084ac08..092537c92beb44087e7adc21f645168c1aed5fe1 100644 (file)
--- a/encoder/macroblock.c
+++ b/encoder/macroblock.c
@@ -475,14 +475,14 @@ static void x264_macroblock_encode_skip( x264_t *h )
  *****************************************************************************/
 static void x264_macroblock_encode_pskip( x264_t *h )
 {
-    const int mvx = x264_clip3( h->mb.cache.mv[0][x264_scan8[0]][0],
-                                h->mb.mv_min[0], h->mb.mv_max[0] );
-    const int mvy = x264_clip3( h->mb.cache.mv[0][x264_scan8[0]][1],
-                                h->mb.mv_min[1], h->mb.mv_max[1] );
-
     /* don't do pskip motion compensation if it was already done in macroblock_analyse */
     if( !h->mb.b_skip_mc )
     {
+        int mvx = x264_clip3( h->mb.cache.mv[0][x264_scan8[0]][0],
+                              h->mb.mv_min[0], h->mb.mv_max[0] );
+        int mvy = x264_clip3( h->mb.cache.mv[0][x264_scan8[0]][1],
+                              h->mb.mv_min[1], h->mb.mv_max[1] );
+
         h->mc.mc_luma( h->mb.pic.p_fdec[0],    FDEC_STRIDE,
                        h->mb.pic.p_fref[0][0], h->mb.pic.i_stride[0],
                        mvx, mvy, 16, 16, &h->sh.weight[0][0] );