PR middle-end/91582 - missing heap overflow detection for strcpy

gcc/ChangeLog:

	PR middle-end/91582
	* builtins.c (gimple_call_alloc_size): New function.
	(compute_objsize): Add argument.  Call gimple_call_alloc_size.
	Handle variable offsets and indices.
	* builtins.h (gimple_call_alloc_size): Declare.
	(compute_objsize): Add argument.
	* gcc/gimple-ssa-warn-restrict.c: Remove assertions.
	* tree-ssa-strlen.c (handle_store): Handle calls to allocated objects.

gcc/testsuite/ChangeLog:

	PR middle-end/91582
	* c-c++-common/Wstringop-truncation.c: Remove xfails.
	* g++.dg/warn/Wstringop-overflow-4.C: New test.
	* g++.dg/ext/attr-alloc_size.C: Suppress -Warray-bounds.
	* gcc.dg/Warray-bounds-56.c: New test.
	* gcc.dg/Wstringop-overflow-22.c: New test.
	* gcc.dg/attr-alloc_size.c: Suppress -Warray-bounds.
	* gcc.dg/attr-copy-2.c: Same.
	* gcc.dg/builtin-stringop-chk-5.c: Remove xfails.
	* gcc.dg/builtin-stringop-chk-8.c: Same.  Correct the text of expected
	warnings.
	* gcc.target/i386/pr82002-2a.c: Prune expected warning.
	* gcc.target/i386/pr82002-2b.c: Same.

From-SVN: r278983