PR tree-optimization/45830

	PR tree-optimization/45830
	* stmt.c (expand_switch_using_bit_tests_p): New function.
	(expand_case): Use it.
	* tree.h (expand_switch_using_bit_tests_p): New prototype.
	* tree-switch-conversion.c (struct switch_conv_info): Add
	bit_test_uniq, bit_test_count and bit_test_bb fields.
	(check_range): Fix a comment.
	(check_process_case): Compute bit_test_uniq and bit_test_count.
	(create_temp_arrays): Use XCNEWVEC, merge 3 arrays into one
	allocation.
	(free_temp_arrays): Use XDELETEVEC, adjust for the 3 arrays merging.
	(constructor_contains_same_values_p): Use FOR_EACH_VEC_ELT.
	(array_value_type): New function.
	(build_one_array): Use it, if it returned different type,
	fold_convert all constructor fields and convert back to the
	wider type in the generated code.
	(process_switch): Initialize bit_test_uniq, bit_test_count and
	bit_test_bb fields.  Don't optimize if expand_switch_using_bit_tests_p
	returned true.

	* gcc.target/i386/pr45830.c: New test.
	* gcc.c-torture/execute/pr45830.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@166966 138bc75d-0d04-0410-961f-82ee72b054a4