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

[Florian Hahn via llvm-commits]

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@@ -8858,13 +8794,64 @@ static void addCanonicalIVRecipes(VPlan &Plan, Type *IdxTy, bool HasNUW,
                        {CanonicalIVIncrement, &Plan.getVectorTripCount()}, DL);
 }
 
+static VPValue *addResumeValuesForInduction(VPHeaderPHIRecipe *PhiR,
+                                            VPBuilder &Builder,
+                                            VPBuilder &ScalarPHBuilder,
+                                            VPTypeAnalysis &TypeInfo,
+                                            VPValue *VectorTC) {
+  PHINode *OrigPhi;
+  const InductionDescriptor *ID;
+  VPValue *Start;
+  VPValue *Step;
+  Type *ScalarTy;
+  bool IsCanonical = false;
+  if (auto *WideIV = dyn_cast<VPWidenIntOrFpInductionRecipe>(PhiR)) {
+    if (WideIV->getTruncInst())
+      return nullptr;
+    OrigPhi = cast<PHINode>(WideIV->getUnderlyingValue());
+    ID = &WideIV->getInductionDescriptor();
+    Start = WideIV->getStartValue();
+    Step = WideIV->getStepValue();
+    ScalarTy = WideIV->getScalarType();
+    IsCanonical = WideIV->isCanonical();
+  } else if (auto *WideIV = dyn_cast<VPWidenPointerInductionRecipe>(PhiR)) {
+    OrigPhi = cast<PHINode>(WideIV->getUnderlyingValue());
+    ID = &WideIV->getInductionDescriptor();
+    Start = WideIV->getStartValue();
+    Step = WideIV->getOperand(1);
+    ScalarTy = Start->getLiveInIRValue()->getType();
+  } else {
+    return nullptr;
+  }
+
+  VPValue *EndValue = VectorTC;
+  if (!IsCanonical) {
+    EndValue = Builder.createDerivedIV(
+        ID->getKind(),
+        dyn_cast_or_null<FPMathOperator>(ID->getInductionBinOp()), Start,
+        VectorTC, Step);
+  }
+
+  if (ScalarTy != TypeInfo.inferScalarType(EndValue)) {
+    EndValue = Builder.createScalarCast(Instruction::Trunc, EndValue, ScalarTy);
+  }
+
+  auto *ResumePhiRecipe =
+      ScalarPHBuilder.createNaryOp(VPInstruction::ResumePhi, {EndValue, Start},
+                                   OrigPhi->getDebugLoc(), "bc.resume.val");
+  return ResumePhiRecipe;
+}
+
 /// Create resume phis in the scalar preheader for first-order recurrences and
 /// reductions and update the VPIRInstructions wrapping the original phis in the
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fhahn wrote:

Updated , thanks

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