Regressions on trunk at revision 175007 vs revision 174986

[H.J. Lu ia32 Core 2/i7]

New failures:
FAIL: gcc.dg/guality/pr36728-1.c  -O2 -flto  line 12 arg1 == 1
FAIL: gcc.dg/guality/pr36728-1.c  -O2 -flto  line 14 arg1 == 1
FAIL: gcc.dg/guality/pr36728-1.c  -O2 -flto -flto-partition=none  line 12 arg1 == 1
FAIL: gcc.dg/guality/pr36728-1.c  -O2 -flto -flto-partition=none  line 14 arg1 == 1
FAIL: gcc.dg/guality/vla-1.c  -O2 -flto  line 17 i == 5
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 i == 5
FAIL: gcc.dg/guality/vla-1.c  -O2 -flto -flto-partition=none  line 17 sizeof (a) == 6

New passes:
FAIL: gcc.dg/h8300-bit-insn-ice2.c (test for excess errors)