From c9919949e055dea8f86d50ea7fef70eefd835e00 Mon Sep 17 00:00:00 2001
From: Frej Drejhammar <frej.drejhammar@gmail.com>
Date: Thu, 4 May 2023 11:49:24 +0200
Subject: compiler: Fix bug in SSA-checker

Fix a bug in the SSA-checker where it trashes the environment after
matching a literal bitstring.
---
 lib/compiler/src/beam_ssa_check.erl                      |  5 +++--
 .../test/beam_ssa_check_SUITE_data/sanity_checks.erl     | 16 +++++++++++++++-
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/lib/compiler/src/beam_ssa_check.erl b/lib/compiler/src/beam_ssa_check.erl
index 0d3faa0ee2..f344286943 100644
--- a/lib/compiler/src/beam_ssa_check.erl
+++ b/lib/compiler/src/beam_ssa_check.erl
@@ -285,8 +285,9 @@ env_post1(_Pattern, _Actual, _Env) ->
     ?DP("Failed to match ~p <-> ~p~n", [_Pattern, _Actual]),
     error({internal_pattern_match_error,env_post1}).
 
-post_bitstring(Bytes, Actual, _Env) ->
-    Actual = build_bitstring(Bytes, <<>>).
+post_bitstring(Bytes, Actual, Env) ->
+    Actual = build_bitstring(Bytes, <<>>),
+    Env.
 
 %% Convert the parsed literal binary to an actual bitstring.
 build_bitstring([{integer,_,V}|Bytes], Acc) ->
diff --git a/lib/compiler/test/beam_ssa_check_SUITE_data/sanity_checks.erl b/lib/compiler/test/beam_ssa_check_SUITE_data/sanity_checks.erl
index ae4bb28eea..47c60fd8d6 100644
--- a/lib/compiler/test/beam_ssa_check_SUITE_data/sanity_checks.erl
+++ b/lib/compiler/test/beam_ssa_check_SUITE_data/sanity_checks.erl
@@ -18,6 +18,8 @@
 
 -module(sanity_checks).
 
+-compile(no_ssa_opt_private_append).
+
 -export([check_fail/0,
          check_wrong_pass/0,
          check_xfail/0,
@@ -33,7 +35,9 @@
          t25/0, t26/0, t27/0, t28/0, t29/0,
          t30/0, t31/0, t32/1, t33/1, t34/1,
          t35/1, t36/0, t37/0, t38/0, t39/1,
-         t40/0, t41/0, t42/0, t43/0, t44/0]).
+         t40/0, t41/0, t42/0, t43/0, t44/0,
+
+         check_env/0]).
 
 %% Check that we do not trigger on the wrong pass
 check_wrong_pass() ->
@@ -325,3 +329,13 @@ t44() ->
 %ssa% () when post_ssa_opt ->
 %ssa% _ = call(fun e:f0/1, {...}).
     e:f0({}).
+
+%% Ensure bug which trashed the environment after matching a literal
+%% bitstring stays fixed.
+check_env() ->
+%ssa% () when post_ssa_opt ->
+%ssa% X = bs_create_bin(append, _, <<>>, ...),
+%ssa% ret(X).
+    A = <<>>,
+    B = ex:f(),
+    <<A/binary, B/binary>>.
-- 
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