[llvm] [TTI] Support scalable offsets in getScalingFactorCost (PR #88113)

[Paul Walker via llvm-commits]

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@@ -32,6 +32,8 @@ class Function;
 /// Base class for use as a mix-in that aids implementing
 /// a TargetTransformInfo-compatible class.
 class TargetTransformInfoImplBase {
+  friend class TargetTransformInfo;
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paulwalker-arm wrote:

I just wondered why this is needed?

https://github.com/llvm/llvm-project/pull/88113