ifcvt.c (find_if_case_1): Reinstate 2005-01-04 change...

	* ifcvt.c (find_if_case_1): Reinstate 2005-01-04 change, now that
	the latent bug in rtl_delete_block has been resolved.

From-SVN: r93085

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f4da603a967b296bff13c18d67a4cbf3f393faaa..efe3238c757cd355860d55eeca7ddb321a54916b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2005-01-08  Roger Sayle  <roger@eyesopen.com>
+
+       * ifcvt.c (find_if_case_1): Reinstate 2005-01-04 change, now that
+       the latent bug in rtl_delete_block has been resolved.
+
 2005-01-08  Richard Sandiford  <rsandifo@redhat.com>
 
        * config/mips/t-iris6 (MULTILIB_DIRNAMES): Use -mabi argument values.

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index 98fbd667a01ac2dca65c09259a75ae4e41487000..5eea041d4047add13aed4250164f0d0e8c0ff52f 100644 (file)
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -2927,7 +2927,22 @@ find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
              else_bb->global_live_at_start,
              then_bb->global_live_at_end);
 
-  new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb), else_bb);
+
+  /* We can avoid creating a new basic block if then_bb is immediately
+     followed by else_bb, i.e. deleting then_bb allows test_bb to fall
+     thru to else_bb.  */
+
+  if (then_bb->next_bb == else_bb
+      && then_bb->prev_bb == test_bb
+      && else_bb != EXIT_BLOCK_PTR)
+    {
+      redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
+      new_bb = 0;
+    }
+  else
+    new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
+                                             else_bb);
+
   then_bb_index = then_bb->index;
   delete_basic_block (then_bb);