2015-10-19  Richard Biener  <rguenther@suse.de>

	* gimple-fold.c (gimple_phi_nonnegative_warnv_p): New function.
	(gimple_stmt_nonnegative_warnv_p): Use it.
	* match.pd (CPROJ): New operator list.
	(cproj (complex ...)): Move simplifications from ...
	* builtins.c (fold_builtin_cproj): ... here.

	* gcc.dg/torture/builtin-cproj-1.c: Skip for -O0.

From-SVN: r228970