commit 31d192794f0c76ae848075d1604e6932026a40f8
author Yaowu Xu <yaowu@google.com> Tue Jun 20 08:07:37 2017 -0700
committer Sebastien Alaiwan <sebastien.alaiwan@allegrodvt.com> Tue Jun 20 16:51:36 2017 +0000
tree f03bd5807e9a853d43943ec715b66a66a54d8f5a
parent 23198661a697b800be011083531242e5c39fdf13

Avoid left shift of negative values

changes shifts to multiplications

BUG=aomedia:617

Change-Id: I46a7b3b5d566f8c671e54d8cb876cc53fdc5009d

av1/common/reconintra.c

diff --git a/av1/common/reconintra.c b/av1/common/reconintra.c
index 494b996..c8a0a99 100644
--- a/av1/common/reconintra.c
+++ b/av1/common/reconintra.c
@@ -835,7 +835,7 @@
     y = (r << 8) - dy;
     for (c = 0; c < bw; ++c, base1 += base_inc_x, y -= dy) {
       if (base1 >= min_base_x) {
-        shift1 = (x << upsample_above) & 0xFF;
+        shift1 = (x * (1 << upsample_above)) & 0xFF;
 #if CONFIG_INTRA_INTERP
         val =
             intra_subpel_interp(base1, shift1, above, -1, bw - 1, filter_type);
@@ -846,7 +846,7 @@
       } else {
         base2 = y >> frac_bits_y;
         assert(base2 >= -(1 << upsample_left));
-        shift2 = (y << upsample_left) & 0xFF;
+        shift2 = (y * (1 << upsample_left)) & 0xFF;
 #if CONFIG_INTRA_INTERP
         val = intra_subpel_interp(base2, shift2, left, -1, bh - 1, filter_type);
 #else