[llvm] [VPlan] Remove unused first mask op from VPBlendRecipe. (PR #87770)

[via llvm-commits]

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@@ -1932,12 +1932,12 @@ class VPReductionPHIRecipe : public VPHeaderPHIRecipe {
 class VPBlendRecipe : public VPSingleDefRecipe {
 public:
   /// The blend operation is a User of the incoming values and of their
-  /// respective masks, ordered [I0, M0, I1, M1, ...]. Note that a single value
-  /// might be incoming with a full mask for which there is no VPValue.
+  /// respective masks, ordered [I0, I1, M1, ...]. Note that the first incoming
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ayalz wrote:

```suggestion
  /// respective masks, ordered [I0, I1, M1, I2, M2, ...]. Note that the first incoming
```

https://github.com/llvm/llvm-project/pull/87770