Regressions on trunk at revision 255460 vs revision 255438

[H.J. Lu]

New failures:
FAIL: gcc.dg/builtin-stringop-chk-9.c  (test for warnings, line 125)
FAIL: gcc.dg/builtin-stringop-chk-9.c  (test for warnings, line 133)
FAIL: gcc.dg/builtin-stringop-chk-9.c  (test for warnings, line 141)
FAIL: gcc.dg/builtin-stringop-chk-9.c  (test for warnings, line 149)

New passes: