From 185b0745180e6f6f3a4c9c7a41ec8725749cf5bd Mon Sep 17 00:00:00 2001
From: Scott McMurray <scottmcm@users.noreply.github.com>
Date: Sun, 27 Jul 2025 23:23:22 -0700
Subject: [PATCH] Add a MIR test for `align_of_val` on a slice

---
 ..._slice.InstSimplify-after-simplifycfg.diff | 20 +++++++++++++++++++
 tests/mir-opt/instsimplify/align_of_slice.rs  | 13 ++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 tests/mir-opt/instsimplify/align_of_slice.of_val_slice.InstSimplify-after-simplifycfg.diff
 create mode 100644 tests/mir-opt/instsimplify/align_of_slice.rs

diff --git a/tests/mir-opt/instsimplify/align_of_slice.of_val_slice.InstSimplify-after-simplifycfg.diff b/tests/mir-opt/instsimplify/align_of_slice.of_val_slice.InstSimplify-after-simplifycfg.diff
new file mode 100644
index 000000000000..21ba2e250560
--- /dev/null
+++ b/tests/mir-opt/instsimplify/align_of_slice.of_val_slice.InstSimplify-after-simplifycfg.diff
@@ -0,0 +1,20 @@
+- // MIR for `of_val_slice` before InstSimplify-after-simplifycfg
++ // MIR for `of_val_slice` after InstSimplify-after-simplifycfg
+  
+  fn of_val_slice(_1: &[T]) -> usize {
+      debug slice => _1;
+      let mut _0: usize;
+      let mut _2: *const [T];
+  
+      bb0: {
+          StorageLive(_2);
+          _2 = &raw const (*_1);
+          _0 = std::intrinsics::align_of_val::<[T]>(move _2) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          StorageDead(_2);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/instsimplify/align_of_slice.rs b/tests/mir-opt/instsimplify/align_of_slice.rs
new file mode 100644
index 000000000000..900a05c2a8b3
--- /dev/null
+++ b/tests/mir-opt/instsimplify/align_of_slice.rs
@@ -0,0 +1,13 @@
+//@ test-mir-pass: InstSimplify-after-simplifycfg
+//@ needs-unwind
+
+#![crate_type = "lib"]
+#![feature(core_intrinsics)]
+
+// EMIT_MIR align_of_slice.of_val_slice.InstSimplify-after-simplifycfg.diff
+pub fn of_val_slice<T>(slice: &[T]) -> usize {
+    // CHECK-LABEL: fn of_val_slice(_1: &[T])
+    // CHECK: _2 = &raw const (*_1);
+    // CHECK: _0 = std::intrinsics::align_of_val::<[T]>(move _2)
+    unsafe { core::intrinsics::align_of_val(slice) }
+}