Re: [PATCH v3 0/4] ifcvt: Allow if conversion of arithmetic in basic blocks with multiple sets

[Manolis Tsamis <manolis.tsamis@vrull.eu>]

Hi all,

Pinging once more (
https://gcc.gnu.org/pipermail/gcc-patches/2023-August/628820.html).

Manolis

On Mon, Sep 18, 2023 at 11:18 AM Manolis Tsamis <manolis.tsamis@vrull.eu> wrote:
>
> Kind ping for V3 of these ifcvt changes
> https://gcc.gnu.org/pipermail/gcc-patches/2023-August/628820.html
>
> Thanks,
> Manolis
>
> On Wed, Aug 30, 2023 at 1:14 PM Manolis Tsamis <manolis.tsamis@vrull.eu> wrote:
> >
> >
> > noce_convert_multiple_sets has been introduced and extended over time to handle
> > if conversion for blocks with multiple sets. Currently this is focused on
> > register moves and rejects any sort of arithmetic operations.
> >
> > This series is an extension to allow more sequences to take part in if
> > conversion. The first patch is a required change to emit correct code and the
> > second patch whitelists a larger number of operations through
> > bb_ok_for_noce_convert_multiple_sets. The third patch adds support to rewire
> > multiple registers in noce_convert_multiple_sets_1 and refactors the code with
> > a new helper info struct. The fourth patch removes some old code that should
> > not be needed anymore.
> >
> > For targets that have a rich selection of conditional instructions,
> > like aarch64, I have seen an ~5x increase of profitable if conversions for
> > multiple set blocks in SPEC benchmarks. Also tested with a wide variety of
> > benchmarks and I have not seen performance regressions on either x64 / aarch64.
> >
> > Some samples that previously resulted in a branch but now better use these
> > instructions can be seen in the provided test cases.
> >
> > Bootstrapped and tested on AArch64 and x86-64.
> >
> >
> > Changes in v3:
> >         - Add SCALAR_INT_MODE_P check in bb_ok_for_noce_convert_multiple_sets.
> >         - Allow rewiring of multiple regs.
> >         - Refactor code with noce_multiple_sets_info.
> >         - Remove old code for subregs.
> >
> > Manolis Tsamis (4):
> >   ifcvt: handle sequences that clobber flags in
> >     noce_convert_multiple_sets
> >   ifcvt: Allow more operations in multiple set if conversion
> >   ifcvt: Handle multiple rewired regs and refactor
> >     noce_convert_multiple_sets
> >   ifcvt: Remove obsolete code for subreg handling in
> >     noce_convert_multiple_sets
> >
> >  gcc/ifcvt.cc                                  | 403 ++++++++----------
> >  gcc/ifcvt.h                                   |  16 +
> >  .../aarch64/ifcvt_multiple_sets_arithm.c      |  79 ++++
> >  .../aarch64/ifcvt_multiple_sets_rewire.c      |  20 +
> >  4 files changed, 290 insertions(+), 228 deletions(-)
> >  create mode 100644 gcc/testsuite/gcc.target/aarch64/ifcvt_multiple_sets_arithm.c
> >  create mode 100644 gcc/testsuite/gcc.target/aarch64/ifcvt_multiple_sets_rewire.c
> >
> > --
> > 2.34.1
> >