libvpx: Pull from upstream

source/libvpx/vp9/decoder/vp9_decodemv.c

Index: source/libvpx/vp9/decoder/vp9_decodemv.c
===================================================================
--- source/libvpx/vp9/decoder/vp9_decodemv.c	(revision 254565)
+++ source/libvpx/vp9/decoder/vp9_decodemv.c	(working copy)
@@ -257,13 +257,18 @@
   mv->col = ref->col + diff.col;
 }
 
-static REFERENCE_MODE read_reference_mode(VP9_COMMON *cm, const MACROBLOCKD *xd,
-                                          vp9_reader *r) {
-  const int ctx = vp9_get_reference_mode_context(cm, xd);
-  const int mode = vp9_read(r, cm->fc.comp_inter_prob[ctx]);
-  if (!cm->frame_parallel_decoding_mode)
-    ++cm->counts.comp_inter[ctx][mode];
-  return mode;  // SINGLE_REFERENCE or COMPOUND_REFERENCE
+static REFERENCE_MODE read_block_reference_mode(VP9_COMMON *cm,
+                                                const MACROBLOCKD *xd,
+                                                vp9_reader *r) {
+  if (cm->reference_mode == REFERENCE_MODE_SELECT) {
+    const int ctx = vp9_get_reference_mode_context(cm, xd);
+    const int mode = vp9_read(r, cm->fc.comp_inter_prob[ctx]);
+    if (!cm->frame_parallel_decoding_mode)
+      ++cm->counts.comp_inter[ctx][mode];
+    return mode;  // SINGLE_REFERENCE or COMPOUND_REFERENCE
+  } else {
+    return cm->reference_mode;
+  }
 }
 
 // Read the referncence frame
@@ -277,10 +282,7 @@
     ref_frame[0] = vp9_get_segdata(&cm->seg, segment_id, SEG_LVL_REF_FRAME);
     ref_frame[1] = NONE;
   } else {
-    const REFERENCE_MODE mode = (cm->reference_mode == REFERENCE_MODE_SELECT)
-                                      ? read_reference_mode(cm, xd, r)
-                                      : cm->reference_mode;
-
+    const REFERENCE_MODE mode = read_block_reference_mode(cm, xd, r);
     // FIXME(rbultje) I'm pretty sure this breaks segmentation ref frame coding
     if (mode == COMPOUND_REFERENCE) {
       const int idx = cm->ref_frame_sign_bias[cm->comp_fixed_ref];
@@ -356,6 +358,11 @@
   mbmi->uv_mode = read_intra_mode_uv(cm, r, mbmi->mode);
 }
 
+static INLINE int is_mv_valid(const MV *mv) {
+  return mv->row > MV_LOW && mv->row < MV_UPP &&
+         mv->col > MV_LOW && mv->col < MV_UPP;
+}
+
 static INLINE int assign_mv(VP9_COMMON *cm, MB_PREDICTION_MODE mode,
                             int_mv mv[2], int_mv ref_mv[2],
                             int_mv nearest_mv[2], int_mv near_mv[2],
@@ -367,14 +374,10 @@
     case NEWMV: {
       nmv_context_counts *const mv_counts = cm->frame_parallel_decoding_mode ?
                                             NULL : &cm->counts.mv;
-      read_mv(r, &mv[0].as_mv, &ref_mv[0].as_mv,
-              &cm->fc.nmvc, mv_counts, allow_hp);
-      if (is_compound)
-        read_mv(r, &mv[1].as_mv, &ref_mv[1].as_mv,
-                &cm->fc.nmvc, mv_counts, allow_hp);
       for (i = 0; i < 1 + is_compound; ++i) {
-        ret = ret && mv[i].as_mv.row < MV_UPP && mv[i].as_mv.row > MV_LOW;
-        ret = ret && mv[i].as_mv.col < MV_UPP && mv[i].as_mv.col > MV_LOW;
+        read_mv(r, &mv[i].as_mv, &ref_mv[i].as_mv, &cm->fc.nmvc, mv_counts,
+                allow_hp);
+        ret = ret && is_mv_valid(&mv[i].as_mv);
       }
       break;
     }