re PR middle-end/51323 (g++ confuses this with function argument in optimized call)

re PR middle-end/51323 (g++ confuses this with function argument in optimized call)

	PR middle-end/51323
	PR middle-end/50074
	* calls.c (internal_arg_pointer_exp_state): New variable.
	(internal_arg_pointer_based_exp_1,
	internal_arg_pointer_exp_scan): New functions.
	(internal_arg_pointer_based_exp): New function.
	(mem_overlaps_already_clobbered_arg_p): Use it.
	(expand_call): Free internal_arg_pointer_exp_state.cache vector
	and clear internal_arg_pointer_exp_state.scan_start.

	* gcc.c-torture/execute/pr51323.c: New test.

Co-Authored-By: Eric Botcazou <ebotcazou@adacore.com>
From-SVN: r182000