Regressions on native/master at commit r16-2441 vs commit r16-2437 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-2441 vs commit r16-2437 on Linux/x86_64
New failures:

New passes:
FAIL: c-c++-common/ubsan/null-1.c   -O0  (test for excess errors)