Regressions on native/master at commit r16-2515 vs commit r16-2511 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-2515 vs commit r16-2511 on Linux/x86_64
New failures:
FAIL: c-c++-common/ubsan/pr78858.c   -O0  (test for excess errors)

New passes:
FAIL: c-c++-common/ubsan/overflow-div-2.c   -O0  (test for excess errors)