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re PR tree-optimization/55018 (CDDCE pass is too aggressive sometimes with infinite loops and with some functions)

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gcc/
	PR tree-optimization/55018
	* basic-block.h (dfs_find_deadend): New prototype.
	* cfganal.c (dfs_find_deadend): No longer static.  Use bitmap
	instead of sbitmap for visited.
	(flow_dfs_compute_reverse_execute): Use dfs_find_deadend here, too.
	* dominance.c (calc_dfs_tree): If saw_unconnected,
	traverse from dfs_find_deadend of unconnected b
	instead of b directly.

testsuite/
	PR tree-optimization/55018
	* gcc.dg/torture/pr55018.c: New test.


Co-Authored-By: Jakub Jelinek <jakub@redhat.com>

From-SVN: r193047
This commit is contained in:
Steven Bosscher 2012-10-31 21:37:10 +00:00
parent e212c7f56c
commit 03b06a8344
6 changed files with 57 additions and 12 deletions
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12
gcc/ChangeLog
View file

@ -1,3 +1,15 @@
2012-10-31 Steven Bosscher <steven@gcc.gnu.org>
Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/55018
* basic-block.h (dfs_find_deadend): New prototype.
* cfganal.c (dfs_find_deadend): No longer static. Use bitmap
instead of sbitmap for visited.
(flow_dfs_compute_reverse_execute): Use dfs_find_deadend here, too.
* dominance.c (calc_dfs_tree): If saw_unconnected,
traverse from dfs_find_deadend of unconnected b
instead of b directly.
2012-10-31 Eric Botcazou <ebotcazou@adacore.com>
* config/i386/i386.c (ix86_expand_prologue): Emit frame info for the

1
gcc/basic-block.h
View file

@ -787,6 +787,7 @@ extern void remove_fake_exit_edges (void);
extern void add_noreturn_fake_exit_edges (void);
extern void connect_infinite_loops_to_exit (void);
extern int post_order_compute (int *, bool, bool);
extern basic_block dfs_find_deadend (basic_block);
extern int inverted_post_order_compute (int *);
extern int pre_and_rev_post_order_compute (int *, int *, bool);
extern int dfs_enumerate_from (basic_block, int,

16
gcc/cfganal.c
View file

@ -573,7 +573,9 @@ post_order_compute (int *post_order, bool include_entry_exit,
}
/* Helper routine for inverted_post_order_compute.
/* Helper routine for inverted_post_order_compute
flow_dfs_compute_reverse_execute, and the reverse-CFG
deapth first search in dominance.c.
BB has to belong to a region of CFG
unreachable by inverted traversal from the exit.
i.e. there's no control flow path from ENTRY to EXIT
@ -593,19 +595,17 @@ post_order_compute (int *post_order, bool include_entry_exit,
that all blocks in the region are reachable
by starting an inverted traversal from the returned block. */
static basic_block
basic_block
dfs_find_deadend (basic_block bb)
{
sbitmap visited = sbitmap_alloc (last_basic_block);
bitmap_clear (visited);
bitmap visited = BITMAP_ALLOC (NULL);
for (;;)
{
SET_BIT (visited, bb->index);
if (EDGE_COUNT (bb->succs) == 0
|| TEST_BIT (visited, EDGE_SUCC (bb, 0)->dest->index))
|| ! bitmap_set_bit (visited, bb->index))
{
sbitmap_free (visited);
BITMAP_FREE (visited);
return bb;
}
@ -958,7 +958,7 @@ flow_dfs_compute_reverse_execute (depth_first_search_ds data,
/* Determine if there are unvisited basic blocks. */
FOR_BB_BETWEEN (bb, last_unvisited, NULL, prev_bb)
if (!TEST_BIT (data->visited_blocks, bb->index))
return bb;
return dfs_find_deadend (bb);
return NULL;
}

12
gcc/dominance.c
View file

@ -377,14 +377,18 @@ calc_dfs_tree (struct dom_info *di, bool reverse)
{
FOR_EACH_BB_REVERSE (b)
{
basic_block b2;
if (di->dfs_order[b->index])
continue;
bitmap_set_bit (di->fake_exit_edge, b->index);
di->dfs_order[b->index] = di->dfsnum;
di->dfs_to_bb[di->dfsnum] = b;
b2 = dfs_find_deadend (b);
gcc_checking_assert (di->dfs_order[b2->index] == 0);
bitmap_set_bit (di->fake_exit_edge, b2->index);
di->dfs_order[b2->index] = di->dfsnum;
di->dfs_to_bb[di->dfsnum] = b2;
di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block];
di->dfsnum++;
calc_dfs_tree_nonrec (di, b, reverse);
calc_dfs_tree_nonrec (di, b2, reverse);
gcc_checking_assert (di->dfs_order[b->index]);
}
}
}

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2012-10-31 Steven Bosscher <steven@gcc.gnu.org>
Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/55018
* gcc.dg/torture/pr55018.c: New test.
2012-10-31 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/54583

22
gcc/testsuite/gcc.dg/torture/pr55018.c Normal file
View file

@ -0,0 +1,22 @@
/* PR tree-optimization/55018 */
/* { dg-do compile } */
/* { dg-options "-fdump-tree-optimized" } */
void
foo (int x)
{
unsigned int a = 0;
int b = 3;
if (x)
b = 0;
lab:
if (x)
goto lab;
a++;
if (b != 2)
__builtin_printf ("%u", a);
goto lab;
}
/* { dg-final { scan-tree-dump "printf" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */