[llvm] [VPlan] Compute induction end values in VPlan. (PR #112145)

[via llvm-commits]

================
@@ -9079,24 +8979,88 @@ static void addCanonicalIVRecipes(VPlan &Plan, Type *IdxTy, bool HasNUW,
                        {CanonicalIVIncrement, &Plan.getVectorTripCount()}, DL);
 }
 
-/// Create resume phis in the scalar preheader for first-order recurrences and
-/// reductions and update the VPIRInstructions wrapping the original phis in the
-/// scalar header.
-static void addScalarResumePhis(VPRecipeBuilder &Builder, VPlan &Plan) {
+/// Create and return a ResumePhi for \p PhiR, if it is wide induction recipe.
+/// If the induction recipe is not canonical, creates a VPDerivedIVRecipe to
+/// compute the end value of the induction.
+static VPValue *addResumePhiRecipeForInduction(VPHeaderPHIRecipe *PhiR,
+                                               VPBuilder &VectorPHBuilder,
+                                               VPBuilder &ScalarPHBuilder,
+                                               VPTypeAnalysis &TypeInfo,
+                                               VPValue *VectorTC) {
+  auto *WideIV = dyn_cast<VPWidenInductionRecipe>(PhiR);
+  if (!WideIV)
+    return nullptr;
+
----------------
ayalz wrote:

```suggestion

  auto *WideIntOrFp = dyn_cast<VPWidenIntOrFpInductionRecipe>(WideIV));
  // Truncated wide inductions resume from the last lane of their vector value
  // in the last vector iteration which is handled elsewhere.
  if (WidenIntOrFp && WideIntOrFp->getTruncInst())
    return nullptr;
```

https://github.com/llvm/llvm-project/pull/112145