From e6cf5a22e7d52050055385f42aabe0980273be29 Mon Sep 17 00:00:00 2001
From: Folkert de Vries <folkert@folkertdev.nl>
Date: Sat, 17 Jan 2026 14:30:01 +0100
Subject: [PATCH] test u128 passing on linux and windows

---
 compiler/rustc_codegen_ssa/src/mir/block.rs |  5 ++-
 tests/assembly-llvm/tail-call-indirect.rs   |  1 +
 tests/codegen-llvm/tail-call-u128.rs        | 41 +++++++++++++++++++++
 tests/ui/explicit-tail-calls/indirect.rs    |  3 ++
 4 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 tests/codegen-llvm/tail-call-u128.rs

diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 4420e95017dc..0d42ccc1a73c 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -1273,8 +1273,11 @@ fn codegen_call_terminator(
                                     op.val = Ref(arg.val);
                                 }
                                 LocalRef::Operand(arg) => {
+                                    let Ref(place_value) = arg.val else {
+                                        bug!("only `Ref` should use `PassMode::Indirect`");
+                                    };
                                     bx.typed_place_copy(
-                                        arg.val.deref(fn_abi.args[i].layout.align.abi),
+                                        place_value,
                                         tmp.val,
                                         fn_abi.args[i].layout,
                                     );
diff --git a/tests/assembly-llvm/tail-call-indirect.rs b/tests/assembly-llvm/tail-call-indirect.rs
index 106132c974d2..2bc1743a9baf 100644
--- a/tests/assembly-llvm/tail-call-indirect.rs
+++ b/tests/assembly-llvm/tail-call-indirect.rs
@@ -1,4 +1,5 @@
 //@ add-minicore
+//@ min-llvm-version: 22
 //@ assembly-output: emit-asm
 //@ needs-llvm-components: x86
 //@ compile-flags: --target=x86_64-unknown-linux-gnu
diff --git a/tests/codegen-llvm/tail-call-u128.rs b/tests/codegen-llvm/tail-call-u128.rs
new file mode 100644
index 000000000000..25dfc47a2bfe
--- /dev/null
+++ b/tests/codegen-llvm/tail-call-u128.rs
@@ -0,0 +1,41 @@
+//@ add-minicore
+//@ revisions: win linux
+//@ min-llvm-version: 22
+//
+//@ compile-flags: -Copt-level=3
+//@[linux] compile-flags: --target x86_64-unknown-linux-gnu
+//@[linux] needs-llvm-components: x86
+//@[win] compile-flags: --target x86_64-pc-windows-msvc
+//@[win] needs-llvm-components: x86
+
+#![crate_type = "lib"]
+#![feature(no_core, lang_items, explicit_tail_calls)]
+#![allow(incomplete_features)]
+#![no_core]
+
+// Test passing of i128/u128, which is passed directly on x86, but indirectly on win64.
+
+extern crate minicore;
+use minicore::*;
+
+// linux: define noundef i128 @foo(i128 noundef %a, i128 noundef %b)
+// win: define <16 x i8> @foo(ptr {{.*}} %a, ptr {{.*}} %b)
+#[unsafe(no_mangle)]
+#[inline(never)]
+extern "C" fn foo(a: u128, b: u128) -> u128 {
+    // linux: start:
+    // linux-NEXT: musttail call noundef i128 @bar(i128 noundef %b, i128 noundef %a)
+    //
+    //
+    // win: start:
+    // win-NEXT: %0 = load i128, ptr %b
+    // win-NEXT: %1 = load i128, ptr %a
+    // win-NEXT: store i128 %0, ptr %a
+    // win-NEXT: store i128 %1, ptr %b
+    // win-NEXT: musttail call <16 x i8> @bar(ptr {{.*}} %a, ptr {{.*}} %b)
+    become bar(b, a)
+}
+
+unsafe extern "C" {
+    safe fn bar(a: u128, b: u128) -> u128;
+}
diff --git a/tests/ui/explicit-tail-calls/indirect.rs b/tests/ui/explicit-tail-calls/indirect.rs
index a3d38001e9f4..537976b7f6f4 100644
--- a/tests/ui/explicit-tail-calls/indirect.rs
+++ b/tests/ui/explicit-tail-calls/indirect.rs
@@ -1,5 +1,8 @@
 //@ run-pass
 //@ ignore-backends: gcc
+//
+//@ ignore-wasm
+//@ ignore-riscv64
 #![feature(explicit_tail_calls)]
 #![expect(incomplete_features)]