revert: re PR tree-optimization/32586 (New VN misses FRE opportunities)

revert: re PR tree-optimization/32586 (New VN misses FRE opportunities)

2007-09-07  Richard Guenther  <rguenther@suse.de>

        Revert
        2007-09-06  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/32586
	* tree-ssa-sccvn.c (simplify_binary_expression): Avoid
	folding if nothing changed.
	(simplify_unary_expression): New function.  Do tree combining
	on conversion like codes.
	(try_to_simplify): Call it.

	* g++.dg/tree-ssa/pr27090.C: Remove XFAILs.
	* gcc.dg/tree-ssa/ssa-fre-1.c: Likewise.
	* gcc.dg/tree-ssa/ssa-fre-3.c: Likewise.
	* gcc.dg/tree-ssa/ssa-fre-5.c: Likewise.
	* gcc.dg/tree-ssa/ssa-fre-4.c: Likewise, remove scan for
	now obsolete simplification.

From-SVN: r128236