| Message ID | 20201214221356.68039-1-richard.henderson@linaro.org |
|---|---|
| Headers | show |
| Series | target/s390x: Improve carry computation | expand |
On 14.12.20 23:13, Richard Henderson 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. > LGTM, @Conny, can you pick these? -- Thanks, David / dhildenb
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.