File 0144-compiler-Eliminate-nondeterminism-in-beam_ssa_recv-o.patch of Package erlang

From 13921bfe39b5fe9f849ba8a6fab7349522a81c36 Mon Sep 17 00:00:00 2001
From: Frej Drejhammar <frej.drejhammar@gmail.com>
Date: Wed, 31 May 2023 15:41:29 +0200
Subject: [PATCH] compiler: Eliminate nondeterminism in beam_ssa_recv
 optimization

The beam_ssa_recv optimization builds a list of `recv_marker_clear`
instructions to insert by using `maps:fold/3` in the function
`beam_ssa_recv:plan_clears/2`. The fold iterates over `UsageMap` and
concatenates the lists returned by `beam_ssa_recv:plan_clears_1/3`.
As the iteration order of `maps:fold/3` is undefined, repeated runs
on the same module can produce different results, as the SSA-variables
holding the result of inserted `recv_marker_clear` instructions depend
on the order they are created.

As a compiler developer interested in the effect of optimizations on
the SSA-level (using for example, `erlc +dssaopt`) this produces many
non-relevant changes in the SSA output. This patch forces the
iteration order to be defined and makes the output for repeated
compiler runs stable.
---
 lib/compiler/src/beam_ssa_recv.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/compiler/src/beam_ssa_recv.erl b/lib/compiler/src/beam_ssa_recv.erl
index a0d74f137c..d3f01467cc 100644
--- a/lib/compiler/src/beam_ssa_recv.erl
+++ b/lib/compiler/src/beam_ssa_recv.erl
@@ -740,7 +740,7 @@ plan_clears(UsageMap, Graph) ->
                           [] ->
                               Acc
                       end
-              end, #{}, UsageMap).
+              end, #{}, maps:iterator(UsageMap, ordered)).
 
 plan_clears_1([{From, To, branch} | Edges], ActiveRefs, UsageMap) ->
     %% Clear all references that are no longer active on the `To` block.
-- 
2.35.3