[llvm] [CodeGen] Prune headers and move code out of line for build efficiency, NFC (PR #135622)

[Reid Kleckner via llvm-commits]

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@@ -49,6 +49,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "X86TargetTransformInfo.h"
+#include "llvm/ADT/SmallBitVector.h"
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rnk wrote:

Yes, it was papered over due to transitive includes.

https://github.com/llvm/llvm-project/pull/135622