diff --git a/eval_error.c b/eval_error.c
index 237c96d84f..8f98fcc319 100644
--- a/eval_error.c
+++ b/eval_error.c
@@ -268,7 +268,7 @@ VALUE rb_get_message(VALUE exc);
 void
 rb_ec_error_print(rb_execution_context_t * volatile ec, volatile VALUE errinfo)
 {
-    volatile int raised_flag = ec->raised_flag;
+    volatile uint8_t raised_flag = ec->raised_flag;
     volatile VALUE errat = Qundef;
     volatile VALUE emesg = Qundef;
 
diff --git a/vm_core.h b/vm_core.h
index 9716aff3fc..7b795bb5cb 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -845,8 +845,12 @@ typedef struct rb_execution_context_struct {
     VALUE errinfo;
     VALUE passed_block_handler; /* for rb_iterate */
     const rb_callable_method_entry_t *passed_bmethod_me; /* for bmethod */
-    int raised_flag;
-    enum method_missing_reason method_missing_reason;
+
+    uint8_t raised_flag; /* only 3 bits needed */
+
+    /* n.b. only 7 bits needed, really: */
+    BITFIELD(enum method_missing_reason, method_missing_reason, 8);
+
     VALUE private_const_reference;
 
     /* for GC */