warped motion: fix some UBsan errors.

Fixes the following UBSan errors due to left shifting
negative values.

Change-Id: I578ca3f56417a94ffe83f634171903897117aa6b

av1/common/warped_motion.c

diff --git a/av1/common/warped_motion.c b/av1/common/warped_motion.c
index a0667e6..539b9e0 100644
--- a/av1/common/warped_motion.c
+++ b/av1/common/warped_motion.c
@@ -780,14 +780,14 @@
   if (!is_affine_shear_allowed(wm->alpha, wm->beta, wm->gamma, wm->delta))
     return 0;
 
-  wm->alpha = ROUND_POWER_OF_TWO_SIGNED(wm->alpha, WARP_PARAM_REDUCE_BITS)
-              << WARP_PARAM_REDUCE_BITS;
-  wm->beta = ROUND_POWER_OF_TWO_SIGNED(wm->beta, WARP_PARAM_REDUCE_BITS)
-             << WARP_PARAM_REDUCE_BITS;
-  wm->gamma = ROUND_POWER_OF_TWO_SIGNED(wm->gamma, WARP_PARAM_REDUCE_BITS)
-              << WARP_PARAM_REDUCE_BITS;
-  wm->delta = ROUND_POWER_OF_TWO_SIGNED(wm->delta, WARP_PARAM_REDUCE_BITS)
-              << WARP_PARAM_REDUCE_BITS;
+  wm->alpha = ROUND_POWER_OF_TWO_SIGNED(wm->alpha, WARP_PARAM_REDUCE_BITS) *
+              (1 << WARP_PARAM_REDUCE_BITS);
+  wm->beta = ROUND_POWER_OF_TWO_SIGNED(wm->beta, WARP_PARAM_REDUCE_BITS) *
+             (1 << WARP_PARAM_REDUCE_BITS);
+  wm->gamma = ROUND_POWER_OF_TWO_SIGNED(wm->gamma, WARP_PARAM_REDUCE_BITS) *
+              (1 << WARP_PARAM_REDUCE_BITS);
+  wm->delta = ROUND_POWER_OF_TWO_SIGNED(wm->delta, WARP_PARAM_REDUCE_BITS) *
+              (1 << WARP_PARAM_REDUCE_BITS);
   return 1;
 }
 

av1/common/x86/warp_plane_ssse3.c

diff --git a/av1/common/x86/warp_plane_ssse3.c b/av1/common/x86/warp_plane_ssse3.c
index ce3d531..226729e 100644
--- a/av1/common/x86/warp_plane_ssse3.c
+++ b/av1/common/x86/warp_plane_ssse3.c
@@ -253,10 +253,10 @@
       sx4 += alpha * (-4) + beta * (-4);
       sy4 += gamma * (-4) + delta * (-4);
 
-      sx4 = ROUND_POWER_OF_TWO_SIGNED(sx4, WARP_PARAM_REDUCE_BITS)
-            << WARP_PARAM_REDUCE_BITS;
-      sy4 = ROUND_POWER_OF_TWO_SIGNED(sy4, WARP_PARAM_REDUCE_BITS)
-            << WARP_PARAM_REDUCE_BITS;
+      sx4 = ROUND_POWER_OF_TWO_SIGNED(sx4, WARP_PARAM_REDUCE_BITS) *
+            (1 << WARP_PARAM_REDUCE_BITS);
+      sy4 = ROUND_POWER_OF_TWO_SIGNED(sy4, WARP_PARAM_REDUCE_BITS) *
+            (1 << WARP_PARAM_REDUCE_BITS);
 
       // Horizontal filter
       for (k = -7; k < AOMMIN(8, p_height - i); ++k) {