diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
index a3615611ba..5f39bc586a 100644
--- a/src/arch/x86_64/CodeGen.zig
+++ b/src/arch/x86_64/CodeGen.zig
@@ -3095,7 +3095,8 @@ fn airPopcount(self: *Self, inst: Air.Inst.Index) !void {
             };
             defer if (mat_src_lock) |lock| self.register_manager.unlockReg(lock);
 
-            const dst_mcv: MCValue = if (self.reuseOperand(inst, ty_op.operand, 0, src_mcv))
+            const dst_mcv: MCValue =
+                if (src_mcv.isRegister() and self.reuseOperand(inst, ty_op.operand, 0, src_mcv))
                 src_mcv
             else
                 .{ .register = try self.register_manager.allocReg(inst, gp) };
@@ -5478,6 +5479,9 @@ fn airCmp(self: *Self, inst: Air.Inst.Index, op: math.CompareOperator) !void {
     }
 
     const ty = self.air.typeOf(bin_op.lhs);
+    const abi_size = ty.abiSize(self.target.*);
+    if (abi_size > 8) return self.fail("TODO implement cmp for large values", .{});
+
     const signedness: std.builtin.Signedness = blk: {
         // For non-int types, we treat the values as unsigned
         if (ty.zigTypeTag() != .Int) break :blk .unsigned;
diff --git a/test/behavior/bugs/9584.zig b/test/behavior/bugs/9584.zig
index 307f1689bf..fe3dedcd30 100644
--- a/test/behavior/bugs/9584.zig
+++ b/test/behavior/bugs/9584.zig
@@ -47,6 +47,7 @@ test {
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
 
     var flags = A{
         .a = false,