Auto merge of #69444 - pietroalbini:stable-next-final-v2-new, r=pietroalbini

[stable] Cherry-pick LLVM fix for 1.41.1

This PR cherry-picks the LLVM patch required to properly fix #69225 on 1.41.1, and adds a test to make sure the fix works.

r? @ghost

Author: bors

src/llvm-project

@@ -0,0 +1,33 @@
+// run-fail
+// compile-flags: -C opt-level=3
+// error-pattern: index out of bounds: the len is 0 but the index is 16777216
+// ignore-wasm no panic or subprocess support
+// ignore-emscripten no panic or subprocess support
+
+fn do_test(x: usize) {
+    let mut arr = vec![vec![0u8; 3]];
+
+    let mut z = vec![0];
+    for arr_ref in arr.iter_mut() {
+        for y in 0..x {
+            for _ in 0..1 {
+                z.reserve_exact(x);
+                let iterator = std::iter::repeat(0).take(x);
+                let mut cnt = 0;
+                iterator.for_each(|_| {
+                    z[0] = 0;
+                    cnt += 1;
+                });
+                let a = y * x;
+                let b = (y + 1) * x - 1;
+                let slice = &mut arr_ref[a..b];
+                slice[1 << 24] += 1;
+            }
+        }
+    }
+}
+
+fn main() {
+    do_test(1);
+    do_test(2);
+}