mruby · matz · Aug 16, 2026 · Aug 16, 2026 · Aug 16, 2026
@@ -27,7 +27,12 @@
   #include <mrubyc.h>
   #define mrb_state void
 #else
-  /* May be building standalone mrbc */
+  /* May be building standalone mrbc. mruby.h would declare a core API this
+     binary does not link, but mrbconf.h on its own is self-contained, and it
+     is what settles the target's mrb_int width -- which mrc_int has to match,
+     because this mrbc dumps irep for that target (see MRC_INT32 below). */
+  #include <stdint.h>
+  #include <mrbconf.h>
   #define mrb_state void
 #endif
 
@@ -116,6 +121,13 @@ typedef uint8_t mrc_bool;
 # endif
 #endif
 
+/* mrc_int must be as wide as the VM's mrb_int and no wider: the pool literals
+   and the constant folding below are dumped for a target whose loader rejects
+   an IREP_TT_INT64 entry unless it was built with MRB_INT64 (src/load.c). */
+#if defined(MRB_INT32) && !defined(MRC_INT32)
+#define MRC_INT32 1
+#endif
+
 #if !defined(MRC_INT32)
 #define MRC_INT64 1
 #endif

@@ -3987,30 +3987,32 @@ gen_ensure(mrc_codegen_scope *s, mrc_node *tree, uint32_t catch_entry, uint32_t
 static void
 gen_pm_integer(mrc_codegen_scope *s, const pm_integer_t *iv)
 {
+  mrc_uint value;
+  mrc_bool fits = FALSE;
+
   if (iv->length == 0) {
-    if (!iv->negative) {
-      gen_int(s, cursp(), (mrc_int)iv->value);
-    }
-    else {
-      gen_int(s, cursp(), (mrc_int)iv->value * -1);
-    }
-    return;
+    /* iv->value is a uint32_t, which is wider than mrc_int under MRC_INT32,
+       so the magnitude still has to be range-checked below. */
+    value = iv->value;
+    fits = TRUE;
   }
 #ifdef MRC_INT64
-  if (iv->length == 2) {
-    mrc_uint value = ((mrc_uint)iv->values[0])|((mrc_uint)iv->values[1] << 32);
-    mrc_bool fits = TRUE;
+  else if (iv->length == 2) {
+    value = ((mrc_uint)iv->values[0])|((mrc_uint)iv->values[1] << 32);
+    fits = TRUE;
+  }
+#endif
+  if (fits) {
     if (!iv->negative && MRC_INT_MAX < value) fits = FALSE;
     if (iv->negative) {
       if (value > (mrc_uint)MRC_INT_MIN) fits = FALSE;
       else value *= -1;
     }
-    if (fits) {
-      gen_int(s, cursp(), value);
-      return;
-    }
   }
-#endif
+  if (fits) {
+    gen_int(s, cursp(), (mrc_int)value);
+    return;
+  }
   {
     pm_buffer_t buf = {0};
     pm_integer_string(&buf, iv);

@@ -35,6 +35,27 @@
   assert_equal 10.0, 1.0e+1
 end
 
+assert('Literals Numerical wider than mrb_int') do
+  # None of these fit mrb_int on MRB_INT32, so the compiler has to hand them
+  # to the VM as big integer literals.  A shift is written on the other side
+  # of each because a shift that overflows mrb_int is left to run time, which
+  # gives the same value by a path the literal does not share.  Without
+  # mruby-bigint the value cannot exist at all, and it is the literal that
+  # cannot be built where mrb_int is narrow, the shift where it is wide, so
+  # the guard holds one of each.
+  begin
+    n = 2147483648
+    m = (1 << 63) - 1
+  rescue RangeError
+    skip 'a value here is wider than mrb_int and mruby-bigint is absent'
+  end
+  assert_equal 1 << 31, n
+  assert_equal 4294967296, 1 << 32
+  assert_equal 9223372036854775807, m
+  assert_equal(-2147483649, -(1 << 31) - 1)
+  assert_equal 2147483648, 0x80000000
+end
+
 assert('Literals Strings Single Quoted', '8.7.6.3.2') do
   assert_equal 'abc', 'abc'
   assert_equal '\'', '\''