backport: re PR inline-asm/85172 (internal compiler error: unexpected expression...

backport: re PR inline-asm/85172 (internal compiler error: unexpected expression '<statement>' of kind asm_expr)

	Backported from mainline
	2018-04-04  Jakub Jelinek  <jakub@redhat.com>

	PR inline-asm/85172
	* constexpr.c (cxx_eval_builtin_function_call): For calls to
	builtin_valid_in_constant_expr_p functions, don't call
	cxx_eval_constant_expression if argument is not
	potential_constant_expression.

	* g++.dg/ext/builtin13.C: New test.
	* g++.dg/ext/atomic-4.C: New test.

From-SVN: r261947