https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121814
--- Comment #10 from liwei <liweifriends at gmail dot com> --- @Andrew Pinski : Thanks for the comments. In fact the code I present is just a mimic of one gcc test: https://github.com/gcc-mirror/gcc/blob/41ea9305466ce54027324258aeae9893101941db/libstdc%2B%2B-v3/testsuite/27_io/basic_istream/extractors_arithmetic/char/01.cc#L104
