fold-const.c (build_range_check): If !in_p and recursive call fails, exit immediately.
* fold-const.c (build_range_check): If !in_p and recursive call
fails, exit immediately. If high - low overflows and etype is
a signed type, retry with unsigned etype.
(merge_ranges): If !in0_p and !in1_p, handle even range2 adjacent
to range1 at TYPE_MAX_VALUE and TYPE_MIN_VALUE.
* gcc.dg/range-test-1.c: New test.
* g++.dg/opt/range-test-1.C: New test.