Regressions on master at commit r15-4503 vs commit r15-4497 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r15-4503 vs commit r15-4497 on Linux/x86_64
New failures:

New passes:
FAIL: gcc.dg/torture/convert-dfp.c   -O2 -flto -fuse-linker-plugin 
-fno-fat-lto-objects  (test for excess errors)
FAIL: gfortran.dg/unsigned_38.f90   -O  (test for excess errors)
FAIL: gfortran.dg/unsigned_38.f90   -O  (test for excess errors)