Fully evaluate is_map/1 for literals at load-time

The compiler will only emit is_map/1 instructions with literal
argument if optimization is turned off. Therefore, the only
reason for this commit is cleanliness.

2 files changed, 16 insertions, 2 deletions

diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index f140bb54cc..60f4ab5280 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -4052,6 +4052,20 @@ tuple_append_put(LoaderState* stp, GenOpArg Arity, GenOpArg Dst,
 }
 
 /*
+ * Predicate to test whether the given literal is a map.
+ */
+
+static int
+literal_is_map(LoaderState* stp, GenOpArg Lit)
+{
+    Eterm term;
+
+    ASSERT(Lit.type == TAG_q);
+    term = stp->literals[Lit.val].term;
+    return is_map(term);
+}
+
+/*
  * Predicate to test whether the given literal is an empty map.
  */
 
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index 7993dd9e25..a5a89b3990 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -1489,8 +1489,8 @@ new_map d I I
 update_map_assoc j s d I I
 update_map_exact j s d I I
 
-is_map Fail Literal=q => move Literal x | is_map Fail x
-is_map Fail c => jump Fail
+is_map Fail Lit=q | literal_is_map(Lit) =>
+is_map Fail cq => jump Fail
 
 %macro: is_map IsMap -fail_action
 is_map f r