1 files changed, 11 insertions, 7 deletions
diff --git a/vm_core.h b/vm_core.h
index 94527bbfa6..1011df7276 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -889,13 +889,17 @@ int rb_autoloading_value(VALUE mod, ID id, VALUE* value);
 
 #define sysstack_error GET_VM()->special_exceptions[ruby_error_sysstack]
 
-#define CHECK_VM_STACK_OVERFLOW0(cfp, sp, margin) do { \
-    if ((VALUE *)((char *)((VALUE *)(sp) + (margin)) + sizeof(rb_control_frame_t)) >= ((VALUE *)(cfp))) { \
-	vm_stackoverflow(); \
-    } \
-} while (0)
-
-#define CHECK_VM_STACK_OVERFLOW(cfp, margin) CHECK_VM_STACK_OVERFLOW0((cfp), (cfp)->sp, margin)
+#define RUBY_CONST_ASSERT(expr) (1/!!(expr)) /* expr must be a compile-time constant */
+#define VM_STACK_OVERFLOWED_P(cfp, sp, margin) \
+    (!RUBY_CONST_ASSERT(sizeof(*(sp)) == sizeof(VALUE)) || \
+     !RUBY_CONST_ASSERT(sizeof(*(cfp)) == sizeof(rb_control_frame_t)) || \
+     ((rb_control_frame_t *)((sp) + (margin)) + 1) >= (cfp))
+#define WHEN_VM_STACK_OVERFLOWED(cfp, sp, margin) \
+    if (LIKELY(!VM_STACK_OVERFLOWED_P(cfp, sp, margin))) {(void)0;} else /* overflowed */
+#define CHECK_VM_STACK_OVERFLOW0(cfp, sp, margin) \
+    WHEN_VM_STACK_OVERFLOWED(cfp, sp, margin) vm_stackoverflow()
+#define CHECK_VM_STACK_OVERFLOW(cfp, margin) \
+    WHEN_VM_STACK_OVERFLOWED(cfp, (cfp)->sp, margin) vm_stackoverflow()
 
 /* for thread */