PiNodes with GlobalRefs and Constants

[willtebbutt]

It appears to be the case that, as of 1.11, PiNodes are encountered in the wild which can contain constants. While I don't fully understand why these are necessary, handling them seems important to get e.g. Distributions.jl tests with certain kinds of truncations to work properly.

I believe that this will resolve #303 .

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ
src/interpreter/s2s_reverse_mode_ad.jl	92.65% <100.00%> (+0.06%)	⬆️

[github-actions]

Performance Ratio:
Ratio of time to compute gradient and time to compute function.
Warning: results are very approximate! See here for more context.

┌────────────────────────────┬──────────┬──────────┬─────────────┬─────────┐
│                      Label │ Mooncake │   Zygote │ ReverseDiff │  Enzyme │
│                     String │   String │   String │      String │  String │
├────────────────────────────┼──────────┼──────────┼─────────────┼─────────┤
│                   sum_1000 │     70.1 │      1.0 │         5.5 │ missing │
│                  _sum_1000 │     6.89 │ 325000.0 │        34.2 │ missing │
│               sum_sin_1000 │      2.4 │     1.68 │        10.7 │ missing │
│              _sum_sin_1000 │     2.68 │    213.0 │        13.7 │ missing │
│                   kron_sum │     79.2 │     11.9 │       263.0 │ missing │
│              kron_view_sum │     51.2 │      8.2 │       192.0 │ missing │
│      naive_map_sin_cos_exp │     2.51 │  missing │        7.38 │ missing │
│            map_sin_cos_exp │     2.63 │     1.37 │        5.74 │ missing │
│      broadcast_sin_cos_exp │     2.63 │      3.1 │        1.46 │ missing │
│                 simple_mlp │     4.82 │     3.11 │        6.38 │ missing │
│                     gp_lml │     4.43 │     2.17 │     missing │ missing │
│ turing_broadcast_benchmark │     3.83 │  missing │        28.1 │ missing │
│         large_single_block │     4.06 │   4180.0 │        29.6 │ missing │
└────────────────────────────┴──────────┴──────────┴─────────────┴─────────┘