Regressions on trunk at revision 259592 vs revision 259578

[H.J. Lu ia32 Core i7]

New failures:

New passes:
FAIL: g++.dg/ext/pr84828.C  -std=gnu++11 (internal compiler error)
FAIL: g++.dg/ext/pr84828.C  -std=gnu++11 (test for excess errors)
FAIL: g++.dg/ext/pr84828.C  -std=gnu++14 (internal compiler error)
FAIL: g++.dg/ext/pr84828.C  -std=gnu++14 (test for excess errors)
FAIL: g++.dg/ext/pr84828.C  -std=gnu++98 (internal compiler error)
FAIL: g++.dg/ext/pr84828.C  -std=gnu++98 (test for excess errors)