re PR middle-end/68146 (ice in gimple_stmt_nonnegative_warnv_p with -O2)

re PR middle-end/68146 (ice in gimple_stmt_nonnegative_warnv_p with -O2)

	PR middle-end/68146
	PR tree-optimization/69155
	* tree-complex.c: Include cfganal.h.
	(phis_to_revisit): New variable.
	(extract_component): Add phiarg_p argument.  Assert that returned
	SSA_NAME has non-NULL SSA_NAME_DEF_STMT unless phiarg_p is true.
	(update_phi_components): Partly rewrite to use loop over real/imag
	components instead of code duplication.  If extract_component returns
	SSA_NAME with NULL SSA_NAME_DEF_STMT, store SSA_NAME_VAR or
	create_tmp_reg into the PHI node instead, and mention the phi triplet
	in phis_to_revisit.
	(tree_lower_complex): Walk bbs in rpo order.  Adjust phis recorded
	in phis_to_revisit at the end.

	* gfortran.dg/pr68146.f: New test.
	* gfortran.dg/pr69155.f90: New test.

From-SVN: r232368