[llvm-branch-commits] [llvm] [LV] Mask off possibly aliasing vector lanes (PR #100579)

[Florian Hahn via llvm-branch-commits]

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@@ -8974,11 +8982,104 @@ void LoopVectorizationPlanner::attachRuntimeChecks(
     assert((!CM.OptForSize ||
             CM.Hints->getForce() == LoopVectorizeHints::FK_Enabled) &&
            "Cannot SCEV check stride or overflow when optimizing for size");
-    VPlanTransforms::attachCheckBlock(Plan, SCEVCheckCond, SCEVCheckBlock,
+    VPlanTransforms::attachCheckBlock(Plan, Plan.getOrAddLiveIn(SCEVCheckCond),
+                                      Plan.createVPIRBasicBlock(SCEVCheckBlock),
                                       HasBranchWeights);
   }
   const auto &[MemCheckCond, MemCheckBlock] = RTChecks.getMemRuntimeChecks();
   if (MemCheckBlock && MemCheckBlock->hasNPredecessors(0)) {
+    VPValue *MemCheckCondVPV = Plan.getOrAddLiveIn(MemCheckCond);
+    VPBasicBlock *MemCheckBlockVP = Plan.createVPIRBasicBlock(MemCheckBlock);
+    std::optional<ArrayRef<PointerDiffInfo>> ChecksOpt =
+        CM.Legal->getRuntimePointerChecking()->getDiffChecks();
+
+    // Create a mask enabling safe elements for each iteration.
+    if (CM.getRTCheckStyle(TTI) == RTCheckStyle::UseSafeEltsMask &&
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fhahn wrote:

would be good to outline to a separte function + document the transform


https://github.com/llvm/llvm-project/pull/100579