[llvm] [VPlan] Make CanIV part of region. (PR #144803)

via llvm-commits llvm-commits at lists.llvm.org
Sun Aug 10 05:12:54 PDT 2025


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@@ -894,18 +902,37 @@ void VPRegionBlock::print(raw_ostream &O, const Twine &Indent,
 
 void VPRegionBlock::dissolveToCFGLoop() {
   auto *Header = cast<VPBasicBlock>(getEntry());
-  if (auto *CanIV = dyn_cast<VPCanonicalIVPHIRecipe>(&Header->front())) {
-    assert(this == getPlan()->getVectorLoopRegion() &&
-           "Canonical IV must be in the entry of the top-level loop region");
-    auto *ScalarR = VPBuilder(CanIV).createScalarPhi(
-        {CanIV->getStartValue(), CanIV->getBackedgeValue()},
-        CanIV->getDebugLoc(), "index");
+  auto *ExitingLatch = cast<VPBasicBlock>(getExiting());
+  if (CanIV && CanIV->getNumUsers() > 0) {
+    auto *ExitingTerm = ExitingLatch->getTerminator();
+    VPInstruction *CanIVInc = nullptr;
+    for (VPUser *U : CanIV->users()) {
+      if (match(U, m_Add(m_VPValue(), m_Specific(&getPlan()->getVFxUF())))) {
+        CanIVInc = cast<VPInstruction>(U);
+      }
+    }
+    if (!CanIVInc) {
+      VPValue *Count;
+      if (match(ExitingLatch->getTerminator(),
+                m_BranchOnCount(m_VPValue(Count), m_VPValue())))
----------------
ayalz wrote:

This Count might not be an add of canIV with VFxUF?

https://github.com/llvm/llvm-project/pull/144803


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