For a given block, an entity is either transparent for
all modes or for none. Each update to the transparency set
therefore used a loop like:
for (i = 0; i < no_mode; i++)
clear_mode_bit (transp[bb->index], j, i);
This patch instead starts out with a bit-per-block bitmap
and updates the main bitmap at the end.
This isn't much of a simplification on its own. The main
purpose is to simplify later patches.
gcc/
* mode-switching.cc (optimize_mode_switching): Initially
compute transparency in a bit-per-block bitmap.
---
gcc/mode-switching.cc | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
@@ -556,6 +556,8 @@ optimize_mode_switching (void)
bitmap_vector_clear (antic, last_basic_block_for_fn (cfun));
bitmap_vector_clear (comp, last_basic_block_for_fn (cfun));
+ auto_sbitmap transp_all (last_basic_block_for_fn (cfun));
+
for (j = n_entities - 1; j >= 0; j--)
{
int e = entity_map[j];
@@ -563,6 +565,8 @@ optimize_mode_switching (void)
struct bb_info *info = bb_info[j];
rtx_insn *insn;
+ bitmap_ones (transp_all);
+
/* Determine what the first use (if any) need for a mode of entity E is.
This will be the mode that is anticipatable for this block.
Also compute the initial transparency settings. */
@@ -595,8 +599,7 @@ optimize_mode_switching (void)
ins_pos = NEXT_INSN (ins_pos);
ptr = new_seginfo (no_mode, no_mode, ins_pos, live_now);
add_seginfo (&tail_ptr, ptr);
- for (i = 0; i < no_mode; i++)
- clear_mode_bit (transp[bb->index], j, i);
+ bitmap_clear_bit (transp_all, bb->index);
}
}
@@ -611,8 +614,7 @@ optimize_mode_switching (void)
{
ptr = new_seginfo (last_mode, mode, insn, live_now);
add_seginfo (&tail_ptr, ptr);
- for (i = 0; i < no_mode; i++)
- clear_mode_bit (transp[bb->index], j, i);
+ bitmap_clear_bit (transp_all, bb->index);
any_set_required = true;
last_mode = mode;
}
@@ -643,8 +645,7 @@ optimize_mode_switching (void)
ptr = new_seginfo (last_mode, no_mode, BB_END (bb), live_now);
add_seginfo (&tail_ptr, ptr);
if (last_mode != no_mode)
- for (i = 0; i < no_mode; i++)
- clear_mode_bit (transp[bb->index], j, i);
+ bitmap_clear_bit (transp_all, bb->index);
}
}
if (targetm.mode_switching.entry && targetm.mode_switching.exit)
@@ -667,8 +668,7 @@ optimize_mode_switching (void)
an extra check in make_preds_opaque. We also
need this to avoid confusing pre_edge_lcm when
antic is cleared but transp and comp are set. */
- for (i = 0; i < no_mode; i++)
- clear_mode_bit (transp[bb->index], j, i);
+ bitmap_clear_bit (transp_all, bb->index);
/* Insert a fake computing definition of MODE into entry
blocks which compute no mode. This represents the mode on
@@ -688,6 +688,9 @@ optimize_mode_switching (void)
FOR_EACH_BB_FN (bb, cfun)
{
+ if (!bitmap_bit_p (transp_all, bb->index))
+ clear_mode_bit (transp[bb->index], j, m);
+
if (info[bb->index].seginfo->mode == m)
set_mode_bit (antic[bb->index], j, m);