Fix failed assertion in debug build

Closes #6634
erlang · Jan 6, 2023 · 428dbdd · 428dbdd
1 parent f3e2505
commit 428dbdd
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Showing 2 changed files with 20 additions and 12 deletions.
diff --git a/erts/emulator/beam/jit/x86/instr_common.cpp b/erts/emulator/beam/jit/x86/instr_common.cpp
@@ -1249,12 +1249,10 @@ void BeamModuleAssembler::emit_i_test_arity(const ArgLabel &Fail,
 void BeamModuleAssembler::emit_is_eq_exact(const ArgLabel &Fail,
                                            const ArgSource &X,
                                            const ArgSource &Y) {
-    /* If either argument is known to be an immediate, we can fail immediately
-     * if they're not equal. */
-    if (always_immediate(X) || always_immediate(Y)) {
-        if (!X.isImmed() && !Y.isImmed()) {
-            comment("simplified check since one argument is an immediate");
-        }
+    /* If one argument is known to be an immediate, we can fail
+     * immediately if they're not equal. */
+    if (X.isRegister() && always_immediate(Y)) {
+        comment("simplified check since one argument is an immediate");
 
         cmp_arg(getArgRef(X), Y);
         a.jne(resolve_beam_label(Fail));
@@ -1320,12 +1318,10 @@ void BeamModuleAssembler::emit_i_is_eq_exact_literal(const ArgLabel &Fail,
 void BeamModuleAssembler::emit_is_ne_exact(const ArgLabel &Fail,
                                            const ArgSource &X,
                                            const ArgSource &Y) {
-    /* If either argument is known to be an immediate, we can fail immediately
-     * if they're equal. */
-    if (always_immediate(X) || always_immediate(Y)) {
-        if (!X.isImmed() && !Y.isImmed()) {
-            comment("simplified check since one argument is an immediate");
-        }
+    /* If one argument is known to be an immediate, we can fail
+     * immediately if they're equal. */
+    if (X.isRegister() && always_immediate(Y)) {
+        comment("simplified check since one argument is an immediate");
 
         cmp_arg(getArgRef(X), Y);
         a.je(resolve_beam_label(Fail));

diff --git a/erts/emulator/test/guard_SUITE.erl b/erts/emulator/test/guard_SUITE.erl
@@ -391,6 +391,18 @@ guard_bifs(Config) when is_list(Config) ->
     try_fail_gbif('node/0', 0, xxxx),
     try_fail_gbif('node/1', self(), xxx),
     try_fail_gbif('node/1', yyy, xxx),
+
+    {'EXIT', {function_clause, _}} = catch gh_6634({a,b}),
+    {'EXIT', {function_clause, _}} = catch gh_6634(42),
+
+    ok.
+
+gh_6634(X) when is_tuple(X) andalso not ok ->
+    %% `not ok` would be translated to an is_eq_exact instruction,
+    %% which the JIT would not handle correctly because it had two
+    %% immediate operands. In a release build incorrect code would be
+    %% generated, which might crash the runtime system; in a debug
+    %% build an assertion would fire at load time.
     ok.
 
 try_gbif(Id, X, Y) ->