[llvm] [VPlan] Add VPValue for VF, use it for VPWidenIntOrFpInductionRecipe. (PR #95305)

[Florian Hahn via llvm-commits]

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@@ -928,8 +928,19 @@ void VPlan::prepareToExecute(Value *TripCountV, Value *VectorTripCountV,
 
   IRBuilder<> Builder(State.CFG.PrevBB->getTerminator());
   // FIXME: Model VF * UF computation completely in VPlan.
-  VFxUF.setUnderlyingValue(
-      createStepForVF(Builder, TripCountV->getType(), State.VF, State.UF));
+  Value *RuntimeVF = nullptr;
+  if (VF.getNumUsers()) {
+    RuntimeVF = createStepForVF(Builder, TripCountV->getType(), State.VF, 1);
+    VF.setUnderlyingValue(RuntimeVF);
+    VFxUF.setUnderlyingValue(
+        State.UF > 1 ? Builder.CreateMul(
+                           VF.getLiveInIRValue(),
+                           ConstantInt::get(TripCountV->getType(), State.UF))
+                     : VF.getLiveInIRValue());
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fhahn wrote:

> But we want to set it directly instead, using VF - when the latter is built with getRuntimeVF(
yep, to reduce calls to @vscale .

Updated to use RuntimeVF variable, thanks!

https://github.com/llvm/llvm-project/pull/95305