[llvm] [TTI] Fix haveFastClmul to access inherited DL via thisT() (NFC) (PR #210647)

[Ramkumar Ramachandra via llvm-commits]

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@@ -686,8 +686,8 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
     // FIXME: clmul should really be Promote for any bitwidth under the largest
     // legal bitwidth for clmul. Using IndexTy instead of Ty is a hack to get
     // around that shortcoming.
-    IntegerType *IndexTy =
-        DL.getIndexType(Ty->getContext(), DL.getAllocaAddrSpace());
+    IntegerType *IndexTy = thisT()->DL.getIndexType(
+        Ty->getContext(), thisT()->DL.getAllocaAddrSpace());
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artagnon wrote:

Just add `DataLayout &DL = thisT()->DL` to avoid the unnecessary diff?

https://github.com/llvm/llvm-project/pull/210647