[gcc r17-2352] aarch64: Add C++ testcase for aligned may_alias types [PR124146]

https://gcc.gnu.org/g:71a5babb361165f0be6848e6ad8fb209d486684e

commit r17-2352-g71a5babb361165f0be6848e6ad8fb209d486684e
Author: Kyrylo Tkachov <[email protected]>
Date:   Thu Jul 9 02:35:26 2026 -0700

    aarch64: Add C++ testcase for aligned may_alias types [PR124146]
    
    The existing tests exercise C.  Add a C++ counterpart to the original
    reproducer, which ICEs without the fix and compiles successfully with it.
    
    Pushing to trunk.
    
    gcc/testsuite/ChangeLog:
    
            PR target/124146
            * g++.target/aarch64/pr124146.C: New test.
    
    Signed-off-by: Kyrylo Tkachov <[email protected]>

Diff:
---
 gcc/testsuite/g++.target/aarch64/pr124146.C | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/gcc/testsuite/g++.target/aarch64/pr124146.C b/gcc/testsuite/g++.target/aarch64/pr124146.C
new file mode 100644
index 000000000000..d53141488bc4
--- /dev/null
+++ b/gcc/testsuite/g++.target/aarch64/pr124146.C
@@ -0,0 +1,25 @@
+/* PR target/124146 */
+/* { dg-do compile } */
+/* { dg-options "-O1" } */
+
+/* Verify that the C++ version of the original reproducer does not ICE.  */
+
+long a;
+void *b;
+char c;
+
+long
+foo (void *)
+{
+  typedef __attribute__((__aligned__))
+    __attribute__((__may_alias__)) unsigned long T;
+  a = *(T *) b;
+  return a;
+}
+
+void
+bar (unsigned long)
+{
+  long d = foo (&c);
+  bar (d);
+}