Regressions on native/master at commit r16-2492 vs commit r16-2491 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-2492 vs commit r16-2491 on Linux/x86_64
New failures:
FAIL: c-c++-common/ubsan/pr109107-2.c   -O0  (test for excess errors)

New passes:
FAIL: gcc.dg/tree-ssa/reassoc-23.c (test for excess errors)