6780143: hs203t003 hits SIGSEGV/EXCEPTION_ACCESS_VIOLATION with -XX:+UseCompressedOops Summary: Using r12 as temporary register around call_VM trashes heapbase becausecall_VM doesn't always return immediately to following code (eg forward_exception, popframe and early return support). Reviewed-by: never, kvn

7003860: G1: assert(_cur_alloc_region == NULL || !expect_null_cur_alloc_region) fails Summary: Wrong assumption about expecting the current alloc region expected to be NULL in expand_and_allocate(). Reviewed-by: brutisso, ysr