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re PR rtl-optimization/84058 (RTl partitioning fixup should drag very small blocks back to hot partition)

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PR rtl/84058
	* cfgcleanup.c (try_forward_edges): Do not give up on crossing
	jumps; choose last target that matches the criteria (i.e.
	no partition changes for non-crossing jumps).
	* cfgrtl.c (cfg_layout_redirect_edge_and_branch): Add basic
	support for redirecting crossing jumps to non-crossing.

From-SVN: r259244
This commit is contained in:
Jan Hubicka 2018-04-09 18:33:51 +02:00 committed by Jan Hubicka
parent 13c60208d0
commit 687d5dfe16
3 changed files with 32 additions and 33 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2018-04-09 Jan Hubicka <jh@suse.cz>
PR rtl/84058
* cfgcleanup.c (try_forward_edges): Do not give up on crossing
jumps; choose last target that matches the criteria (i.e.
no partition changes for non-crossing jumps).
* cfgrtl.c (cfg_layout_redirect_edge_and_branch): Add basic
support for redirecting crossing jumps to non-crossing.
2018-04-09 Alexey Brodkin <abrodkin@synopsys.com>
* config/arc/arc.c (arc_expand_prologue): Set stack usage info

41
gcc/cfgcleanup.c
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@ -394,19 +394,6 @@ try_forward_edges (int mode, basic_block b)
edge_iterator ei;
edge e, *threaded_edges = NULL;
/* 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.
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 (JUMP_P (BB_END (b)) && CROSSING_JUMP_P (BB_END (b)))
return false;
for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); )
{
basic_block target, first;
@ -415,6 +402,7 @@ try_forward_edges (int mode, basic_block b)
bool threaded = false;
int nthreaded_edges = 0;
bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0;
bool new_target_threaded = false;
/* Skip complex edges because we don't know how to update them.
@ -431,29 +419,12 @@ try_forward_edges (int mode, basic_block b)
counter = NUM_FIXED_BLOCKS;
goto_locus = e->goto_locus;
/* If we are partitioning hot/cold basic_blocks, we don't want to mess
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 (first != EXIT_BLOCK_PTR_FOR_FN (cfun)
&& JUMP_P (BB_END (first))
&& CROSSING_JUMP_P (BB_END (first)))
return changed;
while (counter < n_basic_blocks_for_fn (cfun))
{
basic_block new_target = NULL;
bool new_target_threaded = false;
may_thread |= (target->flags & BB_MODIFIED) != 0;
if (FORWARDER_BLOCK_P (target)
&& !(single_succ_edge (target)->flags & EDGE_CROSSING)
&& single_succ (target) != EXIT_BLOCK_PTR_FOR_FN (cfun))
{
/* Bypass trivial infinite loops. */
@ -543,8 +514,14 @@ try_forward_edges (int mode, basic_block b)
break;
counter++;
target = new_target;
threaded |= new_target_threaded;
/* Do not turn non-crossing jump to crossing. Depending on target
it may require different instruction pattern. */
if ((e->flags & EDGE_CROSSING)
|| BB_PARTITION (first) == BB_PARTITION (new_target))
{
target = new_target;
threaded |= new_target_threaded;
}
}
if (counter >= n_basic_blocks_for_fn (cfun))

15
gcc/cfgrtl.c
View File

@ -4361,6 +4361,18 @@ cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
if (e->dest == dest)
return e;
if (e->flags & EDGE_CROSSING
&& BB_PARTITION (e->src) == BB_PARTITION (dest)
&& simplejump_p (BB_END (src)))
{
if (dump_file)
fprintf (dump_file,
"Removing crossing jump while redirecting edge form %i to %i\n",
e->src->index, dest->index);
delete_insn (BB_END (src));
e->flags |= EDGE_FALLTHRU;
}
if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)
&& (ret = try_redirect_by_replacing_jump (e, dest, true)))
{
@ -4424,8 +4436,9 @@ cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
else
ret = redirect_branch_edge (e, dest);
fixup_partition_crossing (ret);
/* We don't want simplejumps in the insn stream during cfglayout. */
gcc_assert (!simplejump_p (BB_END (src)));
gcc_assert (!simplejump_p (BB_END (src)) || CROSSING_JUMP_P (BB_END (src)));
df_set_bb_dirty (src);
return ret;