PR middle-end/83688 - check if buffers may overlap when copying strings using sprintf

PR middle-end/83688 - check if buffers may overlap when copying strings using sprintf

gcc/ChangeLog:

	PR middle-end/83688
	* gimple-ssa-sprintf.c (format_result::alias_info): New struct.
	(directive::argno): New member.
	(format_result::aliases, format_result::alias_count): New data members.
	(format_result::append_alias): New member function.
	(fmtresult::dst_offset): New data member.
	(pass_sprintf_length::call_info::dst_origin): New data member.
	(pass_sprintf_length::call_info::dst_field, dst_offset): Same.
	(char_type_p, array_elt_at_offset, field_at_offset): New functions.
	(get_origin_and_offset): Same.
	(format_string): Call it.
	(format_directive): Call append_alias and set directive argument
	number.
	(maybe_warn_overlap): New function.
	(pass_sprintf_length::compute_format_length): Call it.
	(pass_sprintf_length::handle_gimple_call): Initialize new members.
	* gcc/tree-ssa-strlen.c (): Also enable when -Wrestrict is on.

gcc/testsuite/ChangeLog:

	PR tree-optimization/35503
	* gcc.dg/tree-ssa/builtin-sprintf-warn-23.c: New test.

From-SVN: r278098