[llvm] [VPlan] Support VPWidenIntOrFpInductionRecipes with EVL tail folding (PR #144666)

[Luke Lau via llvm-commits]

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@@ -2604,14 +2605,19 @@ expandVPWidenIntOrFpInduction(VPWidenIntOrFpInductionRecipe *WidenIVR,
     Inc = SplatVF;
     Prev = WidenIVR->getLastUnrolledPartOperand();
   } else {
+    if (VPRecipeBase *R = VF->getDefiningRecipe())
+      Builder.setInsertPoint(R->getParent(), std::next(R->getIterator()));
+    Type *VFTy = TypeInfo.inferScalarType(VF);
     // Multiply the vectorization factor by the step using integer or
     // floating-point arithmetic as appropriate.
     if (StepTy->isFloatingPointTy())
       VF = Builder.createScalarCast(Instruction::CastOps::UIToFP, VF, StepTy,
                                     DL);
-    else
+    else if (VFTy->getScalarSizeInBits() > StepTy->getScalarSizeInBits())
       VF =
           Builder.createScalarCast(Instruction::CastOps::Trunc, VF, StepTy, DL);
+    else if (VFTy->getScalarSizeInBits() < StepTy->getScalarSizeInBits())
+      VF = Builder.createScalarCast(Instruction::CastOps::ZExt, VF, StepTy, DL);
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lukel97 wrote:

Good catch, definitely. I think we may also be able to use it for truncating the Start and Step above?

https://github.com/llvm/llvm-project/pull/144666