[SLPVectorizer] Move size checks (NFC) (llvm#159361)

Move size checks inside `isStridedLoad`. In the future we plan to
possibly change the size and type of strided load there.

Author: mgudim

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -2237,8 +2237,7 @@ class BoUpSLP {
   bool isStridedLoad(ArrayRef<Value *> VL, ArrayRef<Value *> PointerOps,
                      ArrayRef<unsigned> Order, const TargetTransformInfo &TTI,
                      const DataLayout &DL, ScalarEvolution &SE,
-                     const bool IsAnyPointerUsedOutGraph, const int64_t Diff,
-                     StridedPtrInfo &SPtrInfo) const;
+                     const int64_t Diff, StridedPtrInfo &SPtrInfo) const;
 
   /// Checks if the given array of loads can be represented as a vectorized,
   /// scatter or just simple gather.
@@ -6822,10 +6821,19 @@ bool BoUpSLP::isStridedLoad(ArrayRef<Value *> VL, ArrayRef<Value *> PointerOps,
                             ArrayRef<unsigned> Order,
                             const TargetTransformInfo &TTI,
                             const DataLayout &DL, ScalarEvolution &SE,
-                            const bool IsAnyPointerUsedOutGraph,
                             const int64_t Diff,
                             StridedPtrInfo &SPtrInfo) const {
   const size_t Sz = VL.size();
+  if (Diff % (Sz - 1) != 0)
+    return false;
+
+  // Try to generate strided load node.
+  auto IsAnyPointerUsedOutGraph = any_of(PointerOps, [&](Value *V) {
+    return isa<Instruction>(V) && any_of(V->users(), [&](User *U) {
+             return !isVectorized(U) && !MustGather.contains(U);
+           });
+  });
+
   const uint64_t AbsoluteDiff = std::abs(Diff);
   Type *ScalarTy = VL.front()->getType();
   auto *VecTy = getWidenedType(ScalarTy, Sz);
@@ -6956,18 +6964,7 @@ BoUpSLP::LoadsState BoUpSLP::canVectorizeLoads(
                                    cast<Instruction>(V), UserIgnoreList);
                              }))
       return LoadsState::CompressVectorize;
-    // Simple check if not a strided access - clear order.
-    bool IsPossibleStrided = *Diff % (Sz - 1) == 0;
-    // Try to generate strided load node.
-    auto IsAnyPointerUsedOutGraph =
-        IsPossibleStrided && any_of(PointerOps, [&](Value *V) {
-          return isa<Instruction>(V) && any_of(V->users(), [&](User *U) {
-                   return !isVectorized(U) && !MustGather.contains(U);
-                 });
-        });
-    if (IsPossibleStrided &&
-        isStridedLoad(VL, PointerOps, Order, *TTI, *DL, *SE,
-                      IsAnyPointerUsedOutGraph, *Diff, SPtrInfo))
+    if (isStridedLoad(VL, PointerOps, Order, *TTI, *DL, *SE, *Diff, SPtrInfo))
       return LoadsState::StridedVectorize;
   }
   if (!TTI->isLegalMaskedGather(VecTy, CommonAlignment) ||