Implement -fsanitize=signed-integer-overflow.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205684 138bc75d-0d04-0410-961f-82ee72b054a4
	PR c/52023
c-family:
	* c-common.c (c_sizeof_or_alignof_type): Add parameter min_alignof
	and check field alignment if set.
	* c-common.h (c_sizeof_or_alignof_type): Update prototype.
	(c_sizeof, c_alignof): Update calls to c_sizeof_or_alignof_type.

c:
	* c-parser.c (c_parser_alignas_specifier): Use
	c_sizeof_or_alignof_type instead of c_alignof.
	(c_parser_alignof_expression): Likewise, with min_alignof
	parameter depending on alignof spelling used.

cp:
	* typeck.c (cxx_sizeof_or_alignof_type): Update call to
	c_sizeof_or_alignof_type.

objc:
	* objc-act.c (objc_synthesize_getter): Update calls to
	c_sizeof_or_alignof_type.

testsuite:
	* gcc.dg/c11-align-6.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205685 138bc75d-0d04-0410-961f-82ee72b054a4