* tree-ssa-dom.c (simplify_rhs_and_lookup_avail_expr): Remove
	reassociation code.
	* passes.c (init_optimization_passes): Run reassociation again
	after loop optimizations.

	* tree-ssa-dom.c (thread_across_edge): Canonicalize condition
	if necessary.
	(optimize_stmt): Ditto.
	(canonicalize_comparison): New function.
	* tree-ssa-operands.c (swap_tree_operands): Make external.
	(get_expr_operands): Stop auto-canonicalization.
	* tree-ssa-reassoc.c: Rewrite.
	(init_optimization_passes): 
	* tree-flow.h (swap_tree_operands): Prototype.
	* Makefile.in (tree-ssa-reassoc.o): Update dependencies.

	* gcc.dg/tree-ssa/ssa-pre-2.c: Update due to reassociation changes.
	* gcc.dg/tree-ssa/reassoc-1.c: Likewise.
	* gcc.dg/tree-ssa/reassoc-2.c: Likewise.
	* gcc.dg/tree-ssa/reassoc-3.c: Likewise.
	* gcc.dg/tree-ssa/reassoc-4.c: Likewise.
	* gcc.dg/tree-ssa/reassoc-5.c: New.
	* gcc.dg/tree-ssa/reassoc-6.c: New.
	* gcc.dg/tree-ssa/reassoc-7.c: New.
	* gcc.dg/tree-ssa/reassoc-8.c: New.
	* gcc.dg/tree-ssa/reassoc-9.c: New.
	* gcc.dg/tree-ssa/reassoc-10.c: New.
	* gcc.dg/tree-ssa/reassoc-11.c: New.

From-SVN: r108425