--- a/tools/profiler/lul/LulMainInt.h
+++ b/tools/profiler/lul/LulMainInt.h
@@ -82,17 +82,17 @@ struct PfxInstr {
   PfxInstr(PfxExprOp opcode, int32_t operand)
     : mOpcode(opcode)
     , mOperand(operand)
   {}
   explicit PfxInstr(PfxExprOp opcode)
     : mOpcode(opcode)
     , mOperand(0)
   {}
-  bool operator==(const PfxInstr& other) {
+  bool operator==(const PfxInstr& other) const {
     return mOpcode == other.mOpcode && mOperand == other.mOperand;
   }
   PfxExprOp mOpcode;
   int32_t   mOperand;
 };
 
 static_assert(sizeof(PfxInstr) <= 8, "PfxInstr size changed unexpectedly");