diff --git a/src/mir/Lowering.cpp b/src/mir/Lowering.cpp
index 8589be99..4bcb494d 100644
--- a/src/mir/Lowering.cpp
+++ b/src/mir/Lowering.cpp
@@ -451,9 +451,8 @@ namespace mir
 
         int lhs = EmitIntValue(bin->GetLhs(), function, value_vregs,
                               scalar_slots, array_slots, block);
-        int rhs = EmitIntValue(bin->GetRhs(), function, value_vregs,
-                              scalar_slots, array_slots, block);
 
+        // Mul by constant power-of-2 → shift left，避免先发射 rhs 再发现不需要的死 MovImm
         if (opcode == Opcode::MulRR)
         {
           auto *rhs_const = dynamic_cast<const ir::ConstantInt *>(bin->GetRhs());
@@ -463,11 +462,7 @@ namespace mir
             if (val > 0 && (val & (val - 1)) == 0)
             {
               int shift = 0;
-              while (val > 1)
-              {
-                val >>= 1;
-                ++shift;
-              }
+              while (val > 1) { val >>= 1; ++shift; }
               block.Append(Opcode::ShlRR,
                            {Operand::VReg(dst, VRegClass::Int),
                             Operand::VReg(lhs, VRegClass::Int),
@@ -478,6 +473,9 @@ namespace mir
           }
         }
 
+        int rhs = EmitIntValue(bin->GetRhs(), function, value_vregs,
+                              scalar_slots, array_slots, block);
+
         if (opcode == Opcode::DivRR)
         {
           auto *rhs_const = dynamic_cast<const ir::ConstantInt *>(bin->GetRhs());