re PR tree-optimization/15353 ([tree-ssa] Merge two "if"s if one subsumes the other.)

re PR tree-optimization/15353 ([tree-ssa] Merge two "if"s if one subsumes the other.)

2007-06-12  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/15353
	PR tree-optimization/31657
	* passes.c (init_optimization_passes): Add pass_tree_ifcombine.
	* timevar.def: Add TV_TREE_IFCOMBINE.
	* tree-pass.h (pass_tree_ifcombine): Declare.
	* tree-ssa-ifcombine.c: New file.
	* tree-ssa-phiopt.c (blocks_in_phiopt_order): Export.
	* tree-flow.h (blocks_in_phiopt_order): Declare.
	* Makefile.in (OBJS-common): Add tree-ssa-ifcombine.o.
	(tree-ssa-ifcombine.o): New dependencies.

	* gcc.c-torture/execute/20070424-1.c: New testcase.
	* gcc.dg/tree-ssa/ssa-ifcombine-1.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ifcombine-2.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ifcombine-3.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ifcombine-4.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ifcombine-5.c: Likewise.

From-SVN: r125644