diff --git a/js/src/jit/MacroAssembler.h b/js/src/jit/MacroAssembler.h
index 7216b57b0955..20291a45af4a 100644
--- a/js/src/jit/MacroAssembler.h
+++ b/js/src/jit/MacroAssembler.h
@@ -1668,7 +1668,7 @@ class MacroAssembler : public MacroAssemblerSpecific {
 
   inline void cmp32LoadPtr(Condition cond, const Address& lhs, Imm32 rhs,
                            const Address& src, Register dest)
-      DEFINED_ON(arm, arm64, x86, x64);
+      DEFINED_ON(arm, arm64, mips_shared, x86, x64);
 
   inline void cmp32MovePtr(Condition cond, Register lhs, Imm32 rhs,
                            Register src, Register dest)
diff --git a/js/src/jit/mips-shared/MacroAssembler-mips-shared-inl.h b/js/src/jit/mips-shared/MacroAssembler-mips-shared-inl.h
index 62e4b4a6dea2..c1e46615effe 100644
--- a/js/src/jit/mips-shared/MacroAssembler-mips-shared-inl.h
+++ b/js/src/jit/mips-shared/MacroAssembler-mips-shared-inl.h
@@ -859,6 +859,14 @@ void MacroAssembler::cmp32Load32(Condition cond, Register lhs, Register rhs,
   bind(&skip);
 }
 
+void MacroAssembler::cmp32LoadPtr(Condition cond, const Address& lhs, Imm32 rhs,
+                                  const Address& src, Register dest) {
+  Label skip;
+  branch32(Assembler::InvertCondition(cond), lhs, rhs, &skip);
+  loadPtr(src, dest);
+  bind(&skip);
+}
+
 void MacroAssembler::test32LoadPtr(Condition cond, const Address& addr,
                                    Imm32 mask, const Address& src,
                                    Register dest) {