diff --git a/src/backend_x64/block_of_code.cpp b/src/backend_x64/block_of_code.cpp
index 2c130b14..25fb630e 100644
--- a/src/backend_x64/block_of_code.cpp
+++ b/src/backend_x64/block_of_code.cpp
@@ -25,6 +25,7 @@ const Xbyak::Reg64 BlockOfCode::ABI_PARAM3 = Xbyak::util::r8;
 const Xbyak::Reg64 BlockOfCode::ABI_PARAM4 = Xbyak::util::r9;
 #else
 const Xbyak::Reg64 BlockOfCode::ABI_RETURN = Xbyak::util::rax;
+const Xbyak::Reg64 BlockOfCode::ABI_RETURN2 = Xbyak::util::rdx;
 const Xbyak::Reg64 BlockOfCode::ABI_PARAM1 = Xbyak::util::rdi;
 const Xbyak::Reg64 BlockOfCode::ABI_PARAM2 = Xbyak::util::rsi;
 const Xbyak::Reg64 BlockOfCode::ABI_PARAM3 = Xbyak::util::rdx;
diff --git a/src/backend_x64/block_of_code.h b/src/backend_x64/block_of_code.h
index f5a47c2a..b814e30a 100644
--- a/src/backend_x64/block_of_code.h
+++ b/src/backend_x64/block_of_code.h
@@ -97,6 +97,9 @@ public:
     void EnsurePatchLocationSize(CodePtr begin, size_t size);
 
     static const Xbyak::Reg64 ABI_RETURN;
+#ifndef _WIN32
+    static const Xbyak::Reg64 ABI_RETURN2;
+#endif
     static const Xbyak::Reg64 ABI_PARAM1;
     static const Xbyak::Reg64 ABI_PARAM2;
     static const Xbyak::Reg64 ABI_PARAM3;