Regressions on master at commit r16-620 vs commit r16-616 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-620 vs commit r16-616 on Linux/x86_64
New failures:

New passes:
FAIL: gcc.target/i386/pr78794.c scan-assembler pandn