[llvm] [LoopVectorize] Generate wide active lane masks (PR #147535)

[David Sherwood via llvm-commits]

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@@ -44,6 +44,7 @@ class VPRecipeBuilder;
 struct VFRange;
 
 extern cl::opt<bool> EnableVPlanNativePath;
+extern cl::opt<bool> EnableWideActiveLaneMask;
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david-arm wrote:

This is useful for testing the new feature, although I guess to enable this by default in future you'll either need a new TTI hook to query the target's preference or compare the costs of using a wider mask + UF extracts with the costs of using UF normal masks and see which is cheapest?

https://github.com/llvm/llvm-project/pull/147535