/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
- and cold sections. */
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
if (flag_reorder_blocks_and_partition
&& (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block)
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
- and cold sections. */
+ and cold sections.
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really m
+ ust be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
if (flag_reorder_blocks_and_partition
&& find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
return false;
counter = 0;
/* If we are partitioning hot/cold basic_blocks, we don't want to mess
- up jumps that cross between hot/cold sections. */
+ up jumps that cross between hot/cold sections.
+
+ Basic block partitioning may result in some jumps that appear
+ to be optimizable (or blocks that appear to be mergeable), but which
+ really must be left untouched (they are required to make it safely
+ across partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete
+ details. */
if (flag_reorder_blocks_and_partition
&& first != EXIT_BLOCK_PTR
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
- and cold sections. */
+ and cold sections.
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
if (flag_reorder_blocks_and_partition
&& (BB_PARTITION (a) != BB_PARTITION (b)
|| find_reg_note (BB_END (a), REG_CROSSING_JUMP, NULL_RTX)))
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
- and cold sections. */
+ and cold sections.
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
if (flag_reorder_blocks_and_partition
&& (find_reg_note (BB_END (a), REG_CROSSING_JUMP, NULL_RTX)
|| BB_PARTITION (a) != BB_PARTITION (b)))
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
- and cold sections. */
+ and cold sections.
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
if (flag_reorder_blocks_and_partition
&& (find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)
|| find_reg_note (BB_END (c), REG_CROSSING_JUMP, NULL_RTX)
newpos1 = newpos2 = NULL_RTX;
/* If we have partitioned hot/cold basic blocks, it is a bad idea
- to try this optimization. */
+ to try this optimization.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
if (flag_reorder_blocks_and_partition && no_new_pseudos)
return false;
/* If we are partitioning hot/cold basic blocks, we don't want to
mess up unconditional or indirect jumps that cross between hot
- and cold sections. */
+ and cold sections.
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
if (flag_reorder_blocks_and_partition
&& (BB_PARTITION (bb->pred->src) != BB_PARTITION (bb->pred->pred_next->src)
|| (bb->pred->flags & EDGE_CROSSING)))