I found that the following two commits caused the difference. https://gcc.gnu.org/git/?p=gcc.git&a=commit;h=2637bd27e86c30bce73f6753e922b1b2f03ad47d https://gcc.gnu.org/git/?p=gcc.git&a=commit;h=e05531efb7fb5ef03d1e62c95c73c87d71e91d49