[llvm] [LoopVectorize] Perform loop versioning for some early exit loops (PR #120603)

[David Sherwood via llvm-commits]

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@@ -2163,6 +2169,27 @@ class GeneratedRTChecks {
 };
 } // namespace
 
+static void addPointerAlignmentChecks(
+    const SmallVectorImpl<std::pair<const SCEV *, Type *>> *Ptrs, Function *F,
+    PredicatedScalarEvolution &PSE, TargetTransformInfo *TTI, ElementCount VF,
+    unsigned IC) {
+  ScalarEvolution *SE = PSE.getSE();
+  const DataLayout &DL = SE->getDataLayout();
+
+  for (auto Ptr : *Ptrs) {
+    Type *PtrIntType = DL.getIntPtrType(Ptr.first->getType());
+    APInt EltSize(PtrIntType->getScalarSizeInBits(),
+                  DL.getTypeStoreSize(Ptr.second).getFixedValue());
+    const SCEV *Start = SE->getPtrToIntExpr(Ptr.first, PtrIntType);
+    const SCEV *ScevEC = SE->getElementCount(PtrIntType, VF * IC);
+    const SCEV *Align =
+        SE->getMulExpr(ScevEC, SE->getConstant(EltSize),
+                       (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW));
+    const SCEV *Rem = SE->getURemExpr(Start, Align);
+    PSE.addPredicate(*(SE->getEqualPredicate(Rem, SE->getZero(PtrIntType))));
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david-arm wrote:

Done

https://github.com/llvm/llvm-project/pull/120603