* stmt.c (emit_case_bit_tests): New routine to implement suitable

	* stmt.c (emit_case_bit_tests): New routine to implement suitable
	switch statements using the equivalent of "if ((1<<x) & cst) ... ".
	(case_bit_test_cmp): New comparison function for "qsort" to order
	case_bit_tests by decreasing number of destination nodes.
	(lshift_cheap_p): New function to determine if "1 << x" is cheap.
	(expand_end_case_type): Use emit_case_bit_tests to implement
	suitable switch statments.
	(CASE_USE_BIT_TESTS): New target macro to disable the above.
	* Makefile.in (stmt.o): Add dependency on optab.h.
	* doc/tm.texi (CASE_USE_BIT_TESTS): Document new target macro.

	* gcc.c-torture/execute/switch-1.c: New test case.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@61784 138bc75d-0d04-0410-961f-82ee72b054a4