Regressions on trunk at revision 171538 vs revision 171450

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

New failures:
FAIL: boehm-gc.c/thread_leak_test.c -O2 (test for excess errors)
FAIL: boehm-gc.c/thread_leak_test.c -O2 (test for excess errors)
FAIL: gcc.dg/guality/vla-1.c  -O2 -flto -flto-partition=none  line 17 sizeof (a) == 6
FAIL: gcc.dg/vect/pr38529.c (internal compiler error)
FAIL: gcc.dg/vect/pr38529.c (internal compiler error)
FAIL: gcc.dg/vect/pr38529.c (test for excess errors)
FAIL: gcc.dg/vect/pr38529.c (test for excess errors)
FAIL: gcc.dg/vect/pr38529.c scan-tree-dump-times vect "OUTER LOOP VECTORIZED" 1
FAIL: gcc.dg/vect/pr38529.c scan-tree-dump-times vect "OUTER LOOP VECTORIZED" 1

New passes: