After processing each outgoing edge of a basic block, try_forward_edges tests
whether the block is a forwarder block. This doesn't make much sense since,
if there are still more than one outgoing edge, then this cannot be a forwarder
block. The attached patch arranges for the test to be done once at the end.
No change in code generation on my set of files, tested on i586-suse-linux,
applied on the mainline.
2011-05-22 Eric Botcazou <ebotca...@adacore.com>
* cfgcleanup.c (try_forward_edges): Do not update BB_FORWARDER_BLOCK.
(try_optimize_cfg): Update BB_FORWARDER_BLOCK if try_forward_edges
returns true.
--
Eric Botcazou
Index: cfgcleanup.c
===================================================================
--- cfgcleanup.c (revision 174027)
+++ cfgcleanup.c (working copy)
@@ -599,9 +599,6 @@ try_forward_edges (int mode, basic_block
+ REG_BR_PROB_BASE / 2)
/ REG_BR_PROB_BASE);
- if (!FORWARDER_BLOCK_P (b) && forwarder_block_p (b))
- b->flags |= BB_FORWARDER_BLOCK;
-
do
{
edge t;
@@ -2693,7 +2690,10 @@ try_optimize_cfg (int mode)
/* Simplify branch to branch. */
if (try_forward_edges (mode, b))
- changed_here = true;
+ {
+ update_forwarder_flag (b);
+ changed_here = true;
+ }
/* Look for shared code between blocks. */
if ((mode & CLEANUP_CROSSJUMP)
