[llvm] [VPlan] Introduce recipes for VP loads and stores. (PR #87816)

[via llvm-commits]

================
@@ -9448,31 +9423,14 @@ void VPWidenStoreRecipe::execute(VPTransformState &State) {
 
     Value *StoredVal = State.get(StoredVPValue, Part);
     if (isReverse()) {
-      assert(!State.EVL && "reversing not yet implemented with EVL");
       // If we store to reverse consecutive memory locations, then we need
       // to reverse the order of elements in the stored value.
       StoredVal = Builder.CreateVectorReverse(StoredVal, "reverse");
       // We don't want to update the value in the map as it might be used in
       // another expression. So don't call resetVectorValue(StoredVal).
     }
     // TODO: split this into several classes for better design.
-    if (State.EVL) {
-      assert(State.UF == 1 && "Expected only UF == 1 when vectorizing with "
-                              "explicit vector length.");
-      assert(cast<VPInstruction>(State.EVL)->getOpcode() ==
-                 VPInstruction::ExplicitVectorLength &&
-             "EVL must be VPInstruction::ExplicitVectorLength.");
-      Value *EVL = State.get(State.EVL, VPIteration(0, 0));
-      // If EVL is not nullptr, then EVL must be a valid value set during plan
-      // creation, possibly default value = whole vector register length. EVL
-      // is created only if TTI prefers predicated vectorization, thus if EVL
-      // is not nullptr it also implies preference for predicated
-      // vectorization.
-      // FIXME: Support reverse store after vp_reverse is added.
-      NewSI = lowerStoreUsingVectorIntrinsics(
-          Builder, State.get(getAddr(), Part, !CreateScatter), StoredVal,
-          CreateScatter, Mask, EVL, Alignment);
-    } else if (CreateScatter) {
+    if (CreateScatter) {
----------------
ayalz wrote:

```suggestion
    Value *Addr = State.get(getAddr(), Part, !CreateScatter);
    if (CreateScatter)
      NewSI =
        Builder.CreateMaskedScatter(StoredVal, Addr, Alignment, Mask);
    else if (Mask)
      NewSI = Builder.CreateMaskedStore(StoredVal, Addr, Alignment, Mask);
    else
      NewSI = Builder.CreateAlignedStore(StoredVal, Addr, Alignment);
```
nit: can be simplified a bit, consistent with VPWidenVPStoreRecipe::execute()?

https://github.com/llvm/llvm-project/pull/87816