Regressions on trunk at revision 254772 vs revision 254751

[H.J. Lu Intel64]

New failures:

New passes:
FAIL: c-c++-common/Wstringop-truncation.c  -std=gnu++14  (test for warnings, line 211)
FAIL: c-c++-common/Wstringop-truncation.c  -std=gnu++14  (test for warnings, line 212)