Merge pull request #6663 from bjorng/bjorn/compiler/fix-try_opt/GH-6660

Fix unsafe optimization of try...after

lib/compiler/src/beam_ssa_opt.erl

@@ -1654,13 +1654,19 @@ sink_try_is(Is) ->
 sink_try_is_1([#b_set{op=kill_try_tag}=Kill | Is], Acc) ->
     [Kill | reverse(Acc, Is)];
 sink_try_is_1([I | Is], Acc) ->
-    case beam_ssa:no_side_effect(I) of
+    case is_safe_sink_try(I) of
         true -> sink_try_is_1(Is, [I | Acc]);
         false -> reverse(Acc, [I | Is])
     end;
 sink_try_is_1([], Acc) ->
     reverse(Acc).
 
+is_safe_sink_try(#b_set{op=Op}=I) ->
+    case Op of
+        bs_extract -> false;
+        _ -> beam_ssa:no_side_effect(I)
+    end.
+
 %% Does a strength reduction of try/catch and catch.
 %%
 %% In try/catch constructs where the expression is restricted

lib/compiler/test/bs_match_SUITE.erl

@@ -2685,6 +2685,9 @@ bs_match(_Config) ->
     ok = do_bs_match_gh_6613(<<0>>),
     <<0,0>> = do_bs_match_gh_6613(<<0,0>>),
 
+    <<"abc">> = do_bs_match_gh_6660(id(<<"abc">>)),
+    {'EXIT', {{try_clause,abc},_}} = catch do_bs_match_gh_6660(id(abc)),
+
     ok.
 
 do_bs_match_1(_, X) ->
@@ -2732,6 +2735,18 @@ do_bs_match_gh_6613(X) ->
     end,
     X.
 
+do_bs_match_gh_6660(X) ->
+    try X of
+        <<Y/bytes>> ->
+            %% The `bs_extract` instruction was sunk to after the
+            %% `kill_try_tag` instruction, preventing
+            %% beam_ssa_pre_codegen from combining it with the
+            %% preceding bs_match instruction.
+            Y
+    after
+        ok
+    end.
+
 %% GH-6348/OTP-18297: Allow aliases for binaries.
 -record(ba_foo, {a,b,c}).