Inline comparisons with literal lists of length one

erts/emulator/beam/jit/arm/instr_common.cpp

@@ -1581,6 +1581,30 @@ void BeamModuleAssembler::emit_is_eq_exact(const ArgLabel &Fail,
         return;
     }
 
+    /* Inline the comparison if the RHS argument is a list of one
+     * immediate value such as `[42]` or `[a]`. */
+    if (Y.isLiteral()) {
+        Eterm literal = beamfile_get_literal(beam, Y.as<ArgLiteral>().get());
+        if (is_list(literal) && is_immed(CAR(list_val(literal))) &&
+            is_nil(CDR(list_val(literal)))) {
+            arm::Gp cons_ptr;
+
+            comment("inlined exact comparison with %T", literal);
+            if (!exact_type<BeamTypeId::Cons>(X)) {
+                emit_is_cons(resolve_beam_label(Fail, dispUnknown), x.reg);
+            }
+            cons_ptr = emit_ptr_val(TMP1, x.reg);
+            a.sub(TMP1, cons_ptr, imm(TAG_PRIMARY_LIST));
+            a.ldp(TMP2, TMP3, arm::Mem(TMP1));
+            cmp(TMP2, CAR(list_val(literal)));
+            mov_imm(TMP4, NIL);
+            a.ccmp(TMP3, TMP4, imm(NZCV::kNone), imm(arm::CondCode::kEQ));
+            a.b_ne(resolve_beam_label(Fail, disp1MB));
+
+            return;
+        }
+    }
+
     /* Both operands are registers or literals. */
     Label next = a.newLabel();
     auto y = load_source(Y, ARG2);