Regressions on native/master at commit r16-3279 vs commit r16-3274 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-3279 vs commit r16-3274 on Linux/x86_64
New failures:

New passes:
FAIL: g++.dg/abi/mangle83.C  -std=c++14 (test for excess errors)
FAIL: g++.dg/abi/mangle83.C  -std=c++14 (test for excess errors)