Benchmark module and top level differences

bench/compiler_optimizations.exs

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+list = Enum.to_list(1..100)
+
+defmodule Compiled do
+  def comprehension(list) do
+    for x <- list, rem(x, 2) == 1, do: x + 1
+  end
+end
+
+# Top level definitions used to be slower than module definitions.
+# These were due to disabled compiler optimizations (no_bool_opt, no_ssa_opt)
+# and have been fixed from elixir 1.16.0-rc.1:
+# https://github.com/elixir-lang/elixir/commit/aabe46536e021da88de39bc5c82c90d97b0604ec#diff-1f4ed234972cb699fe6dc400f3bbf57f72919ef587ba6b1a43441c8b784b0cfb
+
+Benchee.run(%{
+  "module (optimized)" => fn -> Compiled.comprehension(list) end,
+  "top_level (non-optimized)" => fn -> for x <- list, rem(x, 2) == 1, do: x + 1 end
+})

bench/compiler_optimizations.results.old.txt

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+Operating System: macOS
+CPU Information: Apple M1
+Number of Available Cores: 8
+Available memory: 16 GB
+Elixir 1.15.6
+Erlang 26.1.1
+
+Benchmark suite executing with the following configuration:
+warmup: 2 s
+time: 5 s
+memory time: 0 ns
+reduction time: 0 ns
+parallel: 1
+inputs: none specified
+Estimated total run time: 14 s
+
+Benchmarking module (optimized) ...
+Benchmarking top_level (non-optimized) ...
+
+Name                                ips        average  deviation         median         99th %
+module (optimized)               1.74 M      576.11 ns  ±4796.26%         500 ns         667 ns
+top_level (non-optimized)        1.16 M      863.56 ns  ±1966.89%         792 ns         958 ns
+
+Comparison: 
+module (optimized)               1.74 M
+top_level (non-optimized)        1.16 M - 1.50x slower +287.45 ns

bench/compiler_optimizations.results.txt

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+Operating System: macOS
+CPU Information: Apple M1
+Number of Available Cores: 8
+Available memory: 16 GB
+Elixir 1.16.0-rc.1
+Erlang 26.1.1
+
+Benchmark suite executing with the following configuration:
+warmup: 2 s
+time: 5 s
+memory time: 0 ns
+reduction time: 0 ns
+parallel: 1
+inputs: none specified
+Estimated total run time: 14 s
+
+Benchmarking module (optimized) ...
+Benchmarking top_level (non-optimized) ...
+
+Name                                ips        average  deviation         median         99th %
+top_level (non-optimized)        1.77 M      565.93 ns  ±3945.40%         500 ns         667 ns
+module (optimized)               1.72 M      580.88 ns  ±4537.27%         500 ns         667 ns
+
+Comparison: 
+top_level (non-optimized)        1.77 M
+module (optimized)               1.72 M - 1.03x slower +14.95 ns