[clang] [llvm] [PowerPC] Tune AIX shared library TLS model at function level by heuristic (PR #84132)

[Amy Kwan via cfe-commits]

================
@@ -3369,6 +3369,48 @@ SDValue PPCTargetLowering::LowerGlobalTLSAddressAIX(SDValue Op,
   bool Is64Bit = Subtarget.isPPC64();
   bool HasAIXSmallLocalExecTLS = Subtarget.hasAIXSmallLocalExecTLS();
   TLSModel::Model Model = getTargetMachine().getTLSModel(GV);
+  // Initialize heuristic setting lazily:
+  // (1) Use initial-exec for single TLS var reference within current function.
+  // (2) Use local-dynamic for multiple TLS var references within current func.
----------------
amy-kwan wrote:

```suggestion
  // (1) Use initial-exec for single TLS var references within current function.
  // (2) Use local-dynamic for multiple TLS var references within current function.
```
Just wanted to be consistent for the comment.

https://github.com/llvm/llvm-project/pull/84132