Regressions on trunk at revision 172880 vs revision 172872

[H.J. Lu Intel64 Core 2/i7]

New failures:
FAIL: gcc.c-torture/execute/builtins/strlen-3.c execution,  -O2 -flto 
FAIL: gcc.c-torture/execute/builtins/strlen-3.c execution,  -O2 -flto 
FAIL: gcc.c-torture/execute/builtins/strlen-3.c execution,  -O2 -flto -flto-partition=none 
FAIL: gcc.c-torture/execute/builtins/strlen-3.c execution,  -O2 -flto -flto-partition=none 

New passes:
FAIL: gcc.dg/guality/vla-1.c  -O2 -flto -flto-partition=none  line 17 sizeof (a) == 6