Regressions on 4.5 at revision 162497 vs revision 162399

[H.J. Lu ia64]

New failures:
FAIL: gcc.c-torture/execute/builtins/strncat-chk.c compilation,  -Os 
FAIL: gfortran.dg/g77/large_vec.f  -O3 -fomit-frame-pointer  (test for excess errors)
FAIL: gfortran.dg/utf8_1.f03  -Os  (test for excess errors)

New passes:
FAIL: gcc.c-torture/compile/limits-externalid.c  -O2 -flto  (test for excess errors)
FAIL: gfortran.dg/real_const_2.f90  -O3 -fomit-frame-pointer -funroll-all-loops -finline-functions  (test for excess errors)