re PR tree-optimization/45605 (Missed devirtualization)

re PR tree-optimization/45605 (Missed devirtualization)

	PR tree-optimize/45605
	* cgraph.h (const_value_known_p): Declare.
	(varpool_decide_const_value_known): Remove.
	* tree-ssa-ccp.c (get_base_constructor): Use it.
	* lto-cgraph.c (compute_ltrans_boundary): Likewise.
	* expr.c (string_constant): Likewise.
	* tree-ssa-loop-ivcanon.c (constant_after_peeling): Likewise.
	* ipa.c (ipa_discover_readonly_nonaddressable_var,
	function_and_variable_visibility): Likewise.
	* gimplify.c (gimplify_call_expr): Likewise.
	* gimple-fold.c (get_symbol_constant_value): Likewise.
	* varpool.c (varpool_decide_const_value_known): Replace by...
	(const_value_known_p): ... this one; handle other kinds of DECLs
	too and work for automatic vars.
	(varpool_finalize_decl): Use const_value_known_p.

	* lto.c (lto_promote_cross_file_statics): Use const_value_known_p.

	* g++.dg/tree-ssa/pr45605.C: New testcase.

From-SVN: r164438