use indirect return for i128 and f128 on wasm32

Author: folkertdev

compiler/rustc_target/src/callconv/wasm.rs

@@ -27,6 +27,15 @@ where
     if ret.layout.is_aggregate() && !unwrap_trivial_aggregate(cx, ret) {
         ret.make_indirect();
     }
+
+    // `long double`, `__int128t` and `__uint128_t` use an indirect return
+    if let ustc_abi::BackendRepr::Scalar(scalar) = ret.layout.backend_repr {
+        match scalar.primitive() {
+            rustc_abi::Primitive::Int(rustc_abi::Integer::I128, _) => ret.make_indirect(),
+            rustc_abi::Primitive::Float(rustc_abi::Float::F128) => ret.make_indirect(),
+            _ => {}
+        }
+    }
 }
 
 fn classify_arg<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>)