[clang] [llvm] [clang backend] In AArch64's DataLayout, specify a minimum function alignment of 4. (PR #90702)

[Eli Friedman via cfe-commits]

================
@@ -5387,6 +5387,14 @@ std::string llvm::UpgradeDataLayoutString(StringRef DL, StringRef TT) {
     return Res;
   }
 
+  // AArch64 data layout upgrades.
+  if (T.isAArch64()) {
+    // Add "-Fn32"
+    if (!DL.contains("-Fn32"))
+      Res.append("-Fn32");
----------------
efriedma-quic wrote:

Ideally, the "fixed" datalayout string should be in the same order as the one a new compiler would generate (so if you're sticking it at the end here, stick it at the end on the actual strings).  I think we compare datalayouts using string equality in LTO.

https://github.com/llvm/llvm-project/pull/90702