Malloc generated even with __enzyme_allocation_like

[erick-xanadu]

Hi, we have used Enzyme in the past. I recently noticed that there are mallocs and free in the output of Enzyme, even though we register a custom allocation and deallocation function with Enzyme.

@__enzyme_allocation_like = global [4 x ptr] [ptr @_mlir_memref_to_llvm_alloc, ptr null, ptr @dealloc_indices, ptr @_mlir_memref_to_llvm_free]

The mallocs and frees seen are similar to the following:

  %"'mi22_malloccache" = tail call noalias nonnull dereferenceable(24) dereferenceable_or_null(24) ptr @malloc(i64 24), !enzyme_cache_alloc !52
  %"'mi20_malloccache" = tail call noalias nonnull dereferenceable(24) dereferenceable_or_null(24) ptr @malloc(i64 24), !enzyme_cache_alloc !54
  %_malloccache = tail call noalias nonnull dereferenceable(24) dereferenceable_or_null(24) ptr @malloc(i64 24), !enzyme_cache_alloc !56

  tail call void @free(ptr nonnull %_malloccache105), !enzyme_cache_free !62
tail call void @free(ptr nonnull %"'mi16_malloccache"), !enzyme_cache_free !64
tail call void @free(ptr nonnull %"'ip_phi14_malloccache"), !enzyme_cache_free !66
tail call void @free(ptr nonnull %_malloccache147), !enzyme_cache_free !68
tail call void @free(ptr nonnull %subcache152_malloccache), !enzyme_cache_free !70

Do you know if this is expected behaviour? We are using Enzyme version 0.0.130. Thanks!

I was suggested to ping @wsmoses for more visibility.