<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/153144>153144</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [LV][EVL] Try to put it close to addActiveLaneMask()
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
            Mel-Chen
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          Mel-Chen
      </td>
    </tr>
</table>

<pre>
    This work try to move EVL lowering into tryToBuildVPlanWithVPRecipes for removing the following TODO.
```
 // TODO: try to put it close to addActiveLaneMask().
```
The ultimate goal of this work is to move addExplicitVectorLength to:
```
    if (useActiveLaneMask(Style)) {
       ...
    } else if (CM.foldTailWithEVL() && !Plan->hasScalarVFOnly()) {
 VPlanTransforms::runPass(VPlanTransforms::addExplicitVectorLength, *Plan,
 CM.getMaxSafeElements());
    }
```
As an intermediate step, it will first be moved to the beginning of the following for loop: 
```
    for (ElementCount VF = MinVF; ElementCount::isKnownLT(VF, MaxVFTimes2);) {
      VFRange SubRange = {VF, MaxVFTimes2};
      if (auto Plan = tryToBuildVPlanWithVPRecipes(
 std::unique_ptr<VPlan>(VPlan0->duplicate()), SubRange, &LVer)) {

 /* Move  VPlanTransforms::addExplicitVectorLength to  HERE*/

 bool HasScalarVF = Plan->hasScalarVFOnly();
        // Now optimize the initial VPlan.
        if (!HasScalarVF)
 VPlanTransforms::runPass(VPlanTransforms::truncateToMinimalBitwidths,
 *Plan, CM.getMinimalBitwidths());
 //VPlanTransforms::runPass(VPlanTransforms::optimize, *Plan);
 VPlanTransforms::runPass(VPlanTransforms::optimize1, *Plan);
        // TODO: try to put it close to addActiveLaneMask().
        if (CM.foldTailWithEVL() && !HasScalarVF)
 VPlanTransforms::runPass(VPlanTransforms::addExplicitVectorLength,
 *Plan, CM.getMaxSafeElements());
 VPlanTransforms::runPass(VPlanTransforms::optimize2, *Plan);
 assert(verifyVPlanIsValid(*Plan) && "VPlan is invalid");
 VPlans.push_back(std::move(Plan));
      }
      VF = SubRange.End;
 }
```
and then finally into tryToBuildVPlanWithVPRecipes.
</pre>
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