diff --git a/js/src/nanojit/NativeARM.cpp b/js/src/nanojit/NativeARM.cpp
index 2c5dce5e5a9..faa68d5c6c6 100644
--- a/js/src/nanojit/NativeARM.cpp
+++ b/js/src/nanojit/NativeARM.cpp
@@ -2457,7 +2457,8 @@ void
 Assembler::asm_jtbl(LIns* ins, NIns** table)
 {
     Register indexreg = findRegFor(ins->oprnd1(), GpRegs);
-    Register tmp = registerAllocTmp(GpRegs & ~rmask(indexreg));
+    Register tmp = registerAlloc(GpRegs & ~rmask(indexreg));
+    _allocator.addFree(tmp);
     LDR_scaled(PC, tmp, indexreg, 2);      // LDR PC, [tmp + index*4]
     asm_ld_imm(tmp, (int32_t)table);       // tmp = #table
 }