Re: [PATCH v3 0/4] target/s390x: Improve carry computation

[Cornelia Huck]

On Mon, 14 Dec 2020 16:13:52 -0600
Richard Henderson <richard.henderson@linaro.org> wrote:

> While testing the float128_muladd changes for s390x host,
> emulating under x86_64 of course, I noticed that the code
> we generate for strings of ALCGR and SLBGR is pretty awful.
> 
> I realized that we were missing a trick: the output cc is
> based only on the output (result and carry) and so we don't
> need to save the inputs.  And once we do that, we can use
> the output carry as a direct input to the next insn.
> 
> Changes for v3:
>   * Rebased.
> Changes for v2:
>   * Add a few more comments, and enhance the patch descriptions.
> 
> 
> r~
> 
> Richard Henderson (4):
>   target/s390x: Improve cc computation for ADD LOGICAL
>   target/s390x: Improve ADD LOGICAL WITH CARRY
>   target/s390x: Improve cc computation for SUBTRACT LOGICAL
>   target/s390x: Improve SUB LOGICAL WITH BORROW
> 
>  target/s390x/internal.h    |  11 +-
>  target/s390x/cc_helper.c   | 123 +++-------------
>  target/s390x/helper.c      |  10 +-
>  target/s390x/translate.c   | 289 ++++++++++++++++++++-----------------
>  target/s390x/insn-data.def |  76 +++++-----
>  5 files changed, 216 insertions(+), 293 deletions(-)
> 

Thanks, applied.