[llvm] [LV] Check Addr in getAddressAccessSCEV in terms of SCEV expressions. (PR #171204)

[David Sherwood via llvm-commits]

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@@ -150,6 +152,23 @@ const SCEV *vputils::getSCEVExprForVPValue(const VPValue *V,
       .Default([&SE](const VPRecipeBase *) { return SE.getCouldNotCompute(); });
 }
 
+bool vputils::isAddressSCEVForCost(const SCEV *Addr, ScalarEvolution &SE,
+                                   const Loop *L) {
+  // If address is an SCEVAddExpr, all operands must be either be invariant or a
+  // (possibly sign-extend) affine AddRec.
+  if (auto *PtrAdd = dyn_cast<SCEVAddExpr>(Addr)) {
+    return all_of(PtrAdd->operands(), [&SE, L](const SCEV *Op) {
+      return SE.isLoopInvariant(Op, L) ||
+             match(Op, m_scev_SExt(m_scev_AffineAddRec(m_SCEV(), m_SCEV()))) ||
+             match(Op, m_scev_AffineAddRec(m_SCEV(), m_SCEV()));
+    });
+  }
+
+  // Otherwise, check if address is loop invariant or an affine add recurrence.
+  return SE.isLoopInvariant(Addr, L) ||
+         match(Addr, m_scev_AffineAddRec(m_SCEV(), m_SCEV()));
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david-arm wrote:

Why does the sext of a SCEVAddRecExpr not matter here?

https://github.com/llvm/llvm-project/pull/171204