[llvm] [ValueTracking] NFC: Allow tracking values through AddrSpaceCasts (PR #70483)

[Matt Arsenault via llvm-commits]

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@@ -1674,6 +1676,11 @@ class TargetTransformInfo {
 
   /// @}
 
+  std::optional<KnownBits>
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arsenm wrote:

Not much point in making this optional. A direct KnownBits with unknown everything naturally composes without requiring an explicit valid check 

https://github.com/llvm/llvm-project/pull/70483