loopfilter: simplify loop increment

Reported by Monty Montgomery

Change-Id: Ic1547839ab8b9cce3041312a16a9570544e2759c
diff --git a/av1/common/av1_loopfilter.c b/av1/common/av1_loopfilter.c
index 0ed09b5..c12684a 100644
--- a/av1/common/av1_loopfilter.c
+++ b/av1/common/av1_loopfilter.c
@@ -346,7 +346,6 @@
                                  const MACROBLOCKD *const xd, const int plane,
                                  const MACROBLOCKD_PLANE *const plane_ptr,
                                  const uint32_t mi_row, const uint32_t mi_col) {
-  const int row_step = MI_SIZE >> MI_SIZE_LOG2;
   const uint32_t scale_horz = plane_ptr->subsampling_x;
   const uint32_t scale_vert = plane_ptr->subsampling_y;
   uint8_t *const dst_ptr = plane_ptr->dst.buf;
@@ -355,7 +354,7 @@
   const int x_range = (MAX_MIB_SIZE >> scale_horz);
   const int use_highbitdepth = cm->seq_params.use_highbitdepth;
   const aom_bit_depth_t bit_depth = cm->seq_params.bit_depth;
-  for (int y = 0; y < y_range; y += row_step) {
+  for (int y = 0; y < y_range; y++) {
     uint8_t *p = dst_ptr + y * MI_SIZE * dst_stride;
     for (int x = 0; x < x_range;) {
       // inner loop always filter vertical edges in a MI block. If MI size
@@ -433,7 +432,6 @@
                                  const MACROBLOCKD *const xd, const int plane,
                                  const MACROBLOCKD_PLANE *const plane_ptr,
                                  const uint32_t mi_row, const uint32_t mi_col) {
-  const int col_step = MI_SIZE >> MI_SIZE_LOG2;
   const uint32_t scale_horz = plane_ptr->subsampling_x;
   const uint32_t scale_vert = plane_ptr->subsampling_y;
   uint8_t *const dst_ptr = plane_ptr->dst.buf;
@@ -442,7 +440,7 @@
   const int x_range = (MAX_MIB_SIZE >> scale_horz);
   const int use_highbitdepth = cm->seq_params.use_highbitdepth;
   const aom_bit_depth_t bit_depth = cm->seq_params.bit_depth;
-  for (int x = 0; x < x_range; x += col_step) {
+  for (int x = 0; x < x_range; x++) {
     uint8_t *p = dst_ptr + x * MI_SIZE;
     for (int y = 0; y < y_range;) {
       // inner loop always filter vertical edges in a MI block. If MI size
@@ -524,14 +522,13 @@
                                       const MACROBLOCKD_PLANE *const plane_ptr,
                                       const uint32_t mi_row,
                                       const uint32_t mi_col) {
-  const int row_step = MI_SIZE >> MI_SIZE_LOG2;
   const uint32_t scale_horz = plane_ptr->subsampling_x;
   const uint32_t scale_vert = plane_ptr->subsampling_y;
   uint8_t *const dst_ptr = plane_ptr->dst.buf;
   const int dst_stride = plane_ptr->dst.stride;
   const int y_range = cm->mi_rows >> scale_vert;
   const int x_range = cm->mi_cols >> scale_horz;
-  for (int y = 0; y < y_range; y += row_step) {
+  for (int y = 0; y < y_range; y++) {
     uint8_t *p = dst_ptr + y * MI_SIZE * dst_stride;
     for (int x = 0; x < x_range;) {
       // inner loop always filter vertical edges in a MI block. If MI size
@@ -567,14 +564,13 @@
                                       const MACROBLOCKD_PLANE *const plane_ptr,
                                       const uint32_t mi_row,
                                       const uint32_t mi_col) {
-  const int col_step = MI_SIZE >> MI_SIZE_LOG2;
   const uint32_t scale_horz = plane_ptr->subsampling_x;
   const uint32_t scale_vert = plane_ptr->subsampling_y;
   uint8_t *const dst_ptr = plane_ptr->dst.buf;
   const int dst_stride = plane_ptr->dst.stride;
   const int y_range = cm->mi_rows >> scale_vert;
   const int x_range = cm->mi_cols >> scale_horz;
-  for (int x = 0; x < x_range; x += col_step) {
+  for (int x = 0; x < x_range; x++) {
     uint8_t *p = dst_ptr + x * MI_SIZE;
     for (int y = 0; y < y_range;) {
       // inner loop always filter vertical edges in a MI block. If MI size
diff --git a/av1/common/loopfiltermask.c b/av1/common/loopfiltermask.c
index 41d5186..0b68679 100644
--- a/av1/common/loopfiltermask.c
+++ b/av1/common/loopfiltermask.c
@@ -777,14 +777,13 @@
     int plane) {
   const int subsampling_x = plane_ptr->subsampling_x;
   const int subsampling_y = plane_ptr->subsampling_y;
-  const int row_step = (MI_SIZE >> MI_SIZE_LOG2);
   const int is_uv = plane > 0;
   TX_SIZE tx_size = TX_16X16, prev_tx_size = TX_16X16;
   uint8_t level, prev_level = 1;
   uint64_t skip, prev_skip = 0;
   uint64_t is_coding_block_border;
 
-  for (int r = 0; (r << MI_SIZE_LOG2) < plane_ptr->dst.height; r += row_step) {
+  for (int r = 0; (r << MI_SIZE_LOG2) < plane_ptr->dst.height; r++) {
     const int mi_row = r << subsampling_y;
     const int row = mi_row % MI_SIZE_64X64;
     const int row_uv = row | subsampling_y;
@@ -856,14 +855,13 @@
     int plane) {
   const int subsampling_x = plane_ptr->subsampling_x;
   const int subsampling_y = plane_ptr->subsampling_y;
-  const int col_step = (MI_SIZE >> MI_SIZE_LOG2);
   const int is_uv = plane > 0;
   TX_SIZE tx_size = TX_16X16, prev_tx_size = TX_16X16;
   uint8_t level, prev_level = 1;
   uint64_t skip, prev_skip = 0;
   uint64_t is_coding_block_border;
 
-  for (int c = 0; (c << MI_SIZE_LOG2) < plane_ptr->dst.width; c += col_step) {
+  for (int c = 0; (c << MI_SIZE_LOG2) < plane_ptr->dst.width; c++) {
     const int mi_col = c << subsampling_x;
     const int col = mi_col % MI_SIZE_64X64;
     const int col_uv = col | subsampling_x;