Change the ordering of cdce pass

[Easwaran Raman]

The conditional dead call elimination pass shrink wraps certain dead
calls to math functions. It doesn't handle case like this:

D.142420_139 = powD.549 (D.142421_138, D.142419_132);
 fooD.120935.barD.113815 = D.142420_139;
# foo.bar is dead here.

This code gets cleaned up by DCE and leaves only pow, which can then
be shrink-wrapped by cdce. So it seems reasonable to do this
reordering. Bootstraps on x86_64 on linux with no test regression. OK
for trunk?

- Easwaran

----------------------

2012-06-14   Easwaran Raman  <eraman@google.com>

	* gcc/passes.c (init_optimization_passes): Remove pass_call_cdce
	from its current position and insert after pass_dce.

Index: gcc/passes.c
===================================================================
--- gcc/passes.c	(revision 188535)
+++ gcc/passes.c	(working copy)
@@ -1374,7 +1374,6 @@ init_optimization_passes (void)
       NEXT_PASS (pass_complete_unrolli);
       NEXT_PASS (pass_ccp);
       NEXT_PASS (pass_forwprop);
-      NEXT_PASS (pass_call_cdce);
       /* pass_build_alias is a dummy pass that ensures that we
 	 execute TODO_rebuild_alias at this point.  Re-building
 	 alias information also rewrites no longer addressed
@@ -1387,6 +1386,7 @@ init_optimization_passes (void)
       NEXT_PASS (pass_merge_phi);
       NEXT_PASS (pass_vrp);
       NEXT_PASS (pass_dce);
+      NEXT_PASS (pass_call_cdce);
       NEXT_PASS (pass_cselim);
       NEXT_PASS (pass_tree_ifcombine);
       NEXT_PASS (pass_phiopt);