diff --git a/src/backend_x64/hostloc.h b/src/backend_x64/hostloc.h
index 26aeed75..97e09f52 100644
--- a/src/backend_x64/hostloc.h
+++ b/src/backend_x64/hostloc.h
@@ -26,7 +26,7 @@ enum class HostLoc {
 constexpr size_t HostLocCount = static_cast<size_t>(HostLoc::FirstSpill) + SpillCount;
 
 inline bool HostLocIsGPR(HostLoc reg) {
-    return reg >= HostLoc::RAX && reg <= HostLoc::R14;
+    return reg >= HostLoc::RAX && reg <= HostLoc::R15;
 }
 
 inline bool HostLocIsXMM(HostLoc reg) {