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re PR tree-optimization/60280 (gcc.target/arm/ivopts.c and gcc.target/arm/ivopts-2.c failed caused by preserving loop structure.)

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2014-02-28  Richard Biener  <rguenther@suse.de>

	PR target/60280
	* tree-cfgcleanup.c (tree_forwarder_block_p): Restrict
	previous fix and only allow to remove trivial pre-headers
	and latches.  Also honor LOOPS_MAY_HAVE_MULTIPLE_LATCHES.
	(remove_forwarder_block): Properly update the latch of
	a loop.

From-SVN: r208222
This commit is contained in:
Richard Biener 2014-02-28 13:14:23 +00:00 committed by Richard Biener
parent 0618dee54e
commit fba7c56424
2 changed files with 30 additions and 8 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2014-02-28 Richard Biener <rguenther@suse.de>
PR target/60280
* tree-cfgcleanup.c (tree_forwarder_block_p): Restrict
previous fix and only allow to remove trivial pre-headers
and latches. Also honor LOOPS_MAY_HAVE_MULTIPLE_LATCHES.
(remove_forwarder_block): Properly update the latch of
a loop.
2014-02-28 Alexandre Oliva <aoliva@redhat.com>
PR debug/59992

29
gcc/tree-cfgcleanup.c
View File

@ -316,13 +316,22 @@ tree_forwarder_block_p (basic_block bb, bool phi_wanted)
/* Protect loop preheaders and latches if requested. */
if (dest->loop_father->header == dest)
{
if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)
&& bb->loop_father->header != dest)
return false;
if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)
&& bb->loop_father->header == dest)
return false;
if (bb->loop_father == dest->loop_father)
{
if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
return false;
/* If bb doesn't have a single predecessor we'd make this
loop have multiple latches. Don't do that if that
would in turn require disambiguating them. */
return (single_pred_p (bb)
|| loops_state_satisfies_p
(LOOPS_MAY_HAVE_MULTIPLE_LATCHES));
}
else if (bb->loop_father == loop_outer (dest->loop_father))
return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS);
/* Always preserve other edges into loop headers that are
not simple latches or preheaders. */
return false;
}
}
@ -417,6 +426,10 @@ remove_forwarder_block (basic_block bb)
can_move_debug_stmts = MAY_HAVE_DEBUG_STMTS && single_pred_p (dest);
basic_block pred = NULL;
if (single_pred_p (bb))
pred = single_pred (bb);
/* Redirect the edges. */
for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
{
@ -510,7 +523,7 @@ remove_forwarder_block (basic_block bb)
/* Adjust latch infomation of BB's parent loop as otherwise
the cfg hook has a hard time not to kill the loop. */
if (current_loops && bb->loop_father->latch == bb)
bb->loop_father->latch = dest;
bb->loop_father->latch = pred;
/* And kill the forwarder block. */
delete_basic_block (bb);