wrong index for extend

lang/README.md

@@ -612,6 +612,39 @@ main := fn(): uint {
 
 ### Purely Testing Examples
 
+#### null_check_returning_small_global
+```hb
+MAGIC := 127
+get := fn(file: ^u8): ?uint {
+	if *file == MAGIC {
+		return MAGIC
+	} else {
+		return null
+	}
+}
+
+some_file := [u8].(127, 255, 255, 255, 255, 255)
+
+foo := fn(): ?uint {
+	gotten := get(&some_file[0])
+	if gotten == null {
+		return null
+	} else if gotten == 4 {
+		return 2
+	} else if gotten == MAGIC {
+		return 0
+	}
+
+	return null
+}
+
+main := fn(): uint {
+	f := foo()
+	if f == null return 100
+	return f
+}
+```
+
 #### null_check_in_the_loop
 ```hb
 A := struct {

lang/src/son.rs

@@ -4640,6 +4640,7 @@ mod tests {
         fb_driver;
 
         // Purely Testing Examples;
+        null_check_returning_small_global;
         null_check_in_the_loop;
         stack_provenance;
         advanced_floating_point_arithmetic;

lang/src/son/hbvm/their_regalloc.rs

@@ -264,8 +264,8 @@ impl HbvmBackend {
                         } else if let Some(against) = op.cmp_against() {
                             let op_ty = fuc.nodes[rh].ty;
 
-                            self.emit(extend(fuc.nodes[lh].ty, fuc.nodes[lh].ty.extend(), 0, 0));
+                            self.emit(extend(fuc.nodes[lh].ty, fuc.nodes[lh].ty.extend(), 1, 1));
-                            self.emit(extend(fuc.nodes[rh].ty, fuc.nodes[rh].ty.extend(), 1, 1));
+                            self.emit(extend(fuc.nodes[rh].ty, fuc.nodes[rh].ty.extend(), 2, 2));
                             let &[dst, lhs, rhs] = allocs else { unreachable!() };
 
                             if op_ty.is_float() && matches!(op, TokenKind::Le | TokenKind::Ge) {