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

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

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
>