[llvm] [LV]Initial support for safe distance in predicated DataWithEVL vectorization mode. (PR #102897)

[via llvm-commits]

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@@ -1243,6 +1243,11 @@ class VPInstruction : public VPRecipeWithIRFlags {
     SLPLoad,
     SLPStore,
     ActiveLaneMask,
+    /// Creates special scalar explicit-vector-length instruction, which
+    /// calculates the vectorization factor (number of iterations, that can be
+    /// executed simultaneously) at runtime.
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ayalz wrote:

```suggestion
    /// calculates the number of iterations that can
    /// execute simultaneously as a vector at runtime.
```
the term "vectorization factor", VF, is still used to denote the invariant quantity by which the original loop is vectorized, i.e., original-trip-count / vector-trip-count. In case of EVL, could be computed (before the loop) as EVL of first vector iteration.

https://github.com/llvm/llvm-project/pull/102897