[llvm] [VPlan] Update scalar induction resume values in VPlan. (PR #110577)

[Florian Hahn via llvm-commits]

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@@ -2652,26 +2673,27 @@ static Value *getExpandedStep(const InductionDescriptor &ID,
   return I->second;
 }
 
-void InnerLoopVectorizer::createInductionResumeValues(
-    const SCEV2ValueTy &ExpandedSCEVs,
-    std::pair<BasicBlock *, Value *> AdditionalBypass) {
-  assert(((AdditionalBypass.first && AdditionalBypass.second) ||
-          (!AdditionalBypass.first && !AdditionalBypass.second)) &&
-         "Inconsistent information about additional bypass.");
+void InnerLoopVectorizer::createInductionResumeVPValues(
+    const SCEV2ValueTy &ExpandedSCEVs, Value *AdditionalBypassValue) {
   // We are going to resume the execution of the scalar loop.
-  // Go over all of the induction variables that we found and fix the
-  // PHIs that are left in the scalar version of the loop.
-  // The starting values of PHI nodes depend on the counter of the last
-  // iteration in the vectorized loop.
-  // If we come from a bypass edge then we need to start from the original
-  // start value.
-  for (const auto &InductionEntry : Legal->getInductionVars()) {
-    PHINode *OrigPhi = InductionEntry.first;
-    const InductionDescriptor &II = InductionEntry.second;
-    PHINode *BCResumeVal = createInductionResumeValue(
-        OrigPhi, II, getExpandedStep(II, ExpandedSCEVs), LoopBypassBlocks,
-        AdditionalBypass);
-    OrigPhi->setIncomingValueForBlock(LoopScalarPreHeader, BCResumeVal);
+  // Go over all of the induction variable PHIs of the scalar loop header and
+  // fix their starting values, which depend on the counter of the last
+  // iteration of the vectorized loop. If we come from one of the
+  // LoopBypassBlocks then we need to start from the original start value. If we
+  // come from the AdditionalBypass then we need to start from its value.
+  VPBasicBlock *ScalarPHVPBB = Plan.getScalarPreheader();
+  VPBuilder ScalarPHBuilder(ScalarPHVPBB, ScalarPHVPBB->begin());
+  for (VPRecipeBase &R : *Plan.getScalarHeader()) {
+    auto *PhiR = cast<VPIRInstruction>(&R);
+    auto *Phi = dyn_cast<PHINode>(&PhiR->getInstruction());
+    if (!Phi)
+      break;
+    if (!Legal->getInductionVars().contains(Phi))
+      continue;
+    const InductionDescriptor &II = Legal->getInductionVars().find(Phi)->second;
+    createInductionResumeVPValue(PhiR, II, getExpandedStep(II, ExpandedSCEVs),
+                                 LoopBypassBlocks, ScalarPHBuilder,
+                                 AdditionalBypassValue);
----------------
fhahn wrote:

Updated thanks

https://github.com/llvm/llvm-project/pull/110577