Regressions on trunk at revision 173518 vs revision 173516

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

New failures:
FAIL: gcc.dg/guality/vla-1.c  -O2 -flto  line 17 sizeof (a) == 6

New passes:
FAIL: g++.dg/torture/pr48661.C  -O1  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -O1  (test for excess errors)
FAIL: g++.dg/torture/pr48661.C  -O2  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -O2  (test for excess errors)
FAIL: g++.dg/torture/pr48661.C  -O2 -flto  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -O2 -flto  (test for excess errors)
FAIL: g++.dg/torture/pr48661.C  -O2 -flto -flto-partition=none  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -O2 -flto -flto-partition=none  (test for excess errors)
FAIL: g++.dg/torture/pr48661.C  -O3 -fomit-frame-pointer  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -O3 -fomit-frame-pointer  (test for excess errors)
FAIL: g++.dg/torture/pr48661.C  -O3 -g  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -O3 -g  (test for excess errors)
FAIL: g++.dg/torture/pr48661.C  -Os  (internal compiler error)
FAIL: g++.dg/torture/pr48661.C  -Os  (test for excess errors)