Regressions on trunk at revision 178685 vs revision 178680

[Kirill Yukhin [ia32 Core i7 AVX]]

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

New passes: