[Bug target/80080] S390: Isses with emitted cs-instructions for __atomic builtins.

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80080

--- Comment #8 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
The patch has a performance regression on s390x.

  .L1
    lr      %r3,%r1
    cs      %r1,%r4,0(%r2)
    jne     .L1

becomes

  .L1
    cs %r1,%r3,0(%r2)
    ipm %r4
    sra %r4,28
    cijne %r4,0,.L1

Although this can be fixed on s390/s390x in a follow-up patch, I cannot really
prove that something similar won't happen on other targets without testing
them.