diff --git a/src/frontend/A32/types.h b/src/frontend/A32/types.h
index d6b36384..50a76ef8 100644
--- a/src/frontend/A32/types.h
+++ b/src/frontend/A32/types.h
@@ -92,16 +92,14 @@ inline size_t RegNumber(ExtReg reg) {
 }
 
 inline Reg operator+(Reg reg, size_t number) {
-    ASSERT(reg != Reg::INVALID_REG);
-
-    size_t new_reg = static_cast<size_t>(reg) + number;
+    const size_t new_reg = RegNumber(reg) + number;
     ASSERT(new_reg <= 15);
 
     return static_cast<Reg>(new_reg);
 }
 
 inline ExtReg operator+(ExtReg reg, size_t number) {
-    ExtReg new_reg = static_cast<ExtReg>(static_cast<size_t>(reg) + number);
+    const auto new_reg = static_cast<ExtReg>(static_cast<size_t>(reg) + number);
 
     ASSERT((IsSingleExtReg(reg) && IsSingleExtReg(new_reg)) ||
            (IsDoubleExtReg(reg) && IsDoubleExtReg(new_reg)));