[SCEV] Move getIndexExpressionsFromGEP to delinearize [NFC]

llvm/include/llvm/Analysis/Delinearization.h

@@ -21,6 +21,7 @@
 #include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
+class GetElementPtrInst;
 class ScalarEvolution;
 class SCEV;
 
@@ -110,6 +111,20 @@ void delinearize(ScalarEvolution &SE, const SCEV *Expr,
                  SmallVectorImpl<const SCEV *> &Subscripts,
                  SmallVectorImpl<const SCEV *> &Sizes, const SCEV *ElementSize);
 
+/// Gathers the individual index expressions from a GEP instruction.
+///
+/// This function optimistically assumes the GEP references into a fixed size
+/// array. If this is actually true, this function returns a list of array
+/// subscript expressions in \p Subscripts and a list of integers describing
+/// the size of the individual array dimensions in \p Sizes. Both lists have
+/// either equal length or the size list is one element shorter in case there
+/// is no known size available for the outermost array dimension. Returns true
+/// if successful and false otherwise.
+bool getIndexExpressionsFromGEP(ScalarEvolution &SE,
+                                const GetElementPtrInst *GEP,
+                                SmallVectorImpl<const SCEV *> &Subscripts,
+                                SmallVectorImpl<int> &Sizes);
+
 struct DelinearizationPrinterPass
     : public PassInfoMixin<DelinearizationPrinterPass> {
   explicit DelinearizationPrinterPass(raw_ostream &OS);

llvm/include/llvm/Analysis/ScalarEvolution.h

@@ -1104,19 +1104,6 @@ public:
   bool invalidate(Function &F, const PreservedAnalyses &PA,
                   FunctionAnalysisManager::Invalidator &Inv);
 
-  /// Gathers the individual index expressions from a GEP instruction.
-  ///
-  /// This function optimistically assumes the GEP references into a fixed size
-  /// array. If this is actually true, this function returns a list of array
-  /// subscript expressions in \p Subscripts and a list of integers describing
-  /// the size of the individual array dimensions in \p Sizes. Both lists have
-  /// either equal length or the size list is one element shorter in case there
-  /// is no known size available for the outermost array dimension. Returns true
-  /// if successful and false otherwise.
-  bool getIndexExpressionsFromGEP(const GetElementPtrInst *GEP,
-                                  SmallVectorImpl<const SCEV *> &Subscripts,
-                                  SmallVectorImpl<int> &Sizes);
-
   /// Return the DataLayout associated with the module this SCEV instance is
   /// operating on.
   const DataLayout &getDataLayout() const {

llvm/lib/Analysis/Delinearization.cpp

@@ -485,6 +485,44 @@ void llvm::delinearize(ScalarEvolution &SE, const SCEV *Expr,
   });
 }
 
+bool llvm::getIndexExpressionsFromGEP(ScalarEvolution &SE,
+                                      const GetElementPtrInst *GEP,
+                                      SmallVectorImpl<const SCEV *> &Subscripts,
+                                      SmallVectorImpl<int> &Sizes) {
+  assert(Subscripts.empty() && Sizes.empty() &&
+         "Expected output lists to be empty on entry to this function.");
+  assert(GEP && "getIndexExpressionsFromGEP called with a null GEP");
+  Type *Ty = nullptr;
+  bool DroppedFirstDim = false;
+  for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
+    const SCEV *Expr = SE.getSCEV(GEP->getOperand(i));
+    if (i == 1) {
+      Ty = GEP->getSourceElementType();
+      if (auto *Const = dyn_cast<SCEVConstant>(Expr))
+        if (Const->getValue()->isZero()) {
+          DroppedFirstDim = true;
+          continue;
+        }
+      Subscripts.push_back(Expr);
+      continue;
+    }
+
+    auto *ArrayTy = dyn_cast<ArrayType>(Ty);
+    if (!ArrayTy) {
+      Subscripts.clear();
+      Sizes.clear();
+      return false;
+    }
+
+    Subscripts.push_back(Expr);
+    if (!(DroppedFirstDim && i == 2))
+      Sizes.push_back(ArrayTy->getNumElements());
+
+    Ty = ArrayTy->getElementType();
+  }
+  return !Subscripts.empty();
+}
+
 namespace {
 
 class Delinearization : public FunctionPass {

llvm/lib/Analysis/DependenceAnalysis.cpp

@@ -3339,8 +3339,8 @@ bool DependenceInfo::tryDelinearizeFixedSize(
     return false;
 
   SmallVector<int, 4> SrcSizes, DstSizes;
-  SE->getIndexExpressionsFromGEP(SrcGEP, SrcSubscripts, SrcSizes);
-  SE->getIndexExpressionsFromGEP(DstGEP, DstSubscripts, DstSizes);
+  getIndexExpressionsFromGEP(*SE, SrcGEP, SrcSubscripts, SrcSizes);
+  getIndexExpressionsFromGEP(*SE, DstGEP, DstSubscripts, DstSizes);
 
   // Check that the two size arrays are non-empty and equal in length and
   // value.

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -12201,43 +12201,6 @@ const SCEV *ScalarEvolution::getElementSize(Instruction *Inst) {
   return getSizeOfExpr(ETy, Ty);
 }
 
-bool ScalarEvolution::getIndexExpressionsFromGEP(
-    const GetElementPtrInst *GEP, SmallVectorImpl<const SCEV *> &Subscripts,
-    SmallVectorImpl<int> &Sizes) {
-  assert(Subscripts.empty() && Sizes.empty() &&
-         "Expected output lists to be empty on entry to this function.");
-  assert(GEP && "getIndexExpressionsFromGEP called with a null GEP");
-  Type *Ty = nullptr;
-  bool DroppedFirstDim = false;
-  for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
-    const SCEV *Expr = getSCEV(GEP->getOperand(i));
-    if (i == 1) {
-      Ty = GEP->getSourceElementType();
-      if (auto *Const = dyn_cast<SCEVConstant>(Expr))
-        if (Const->getValue()->isZero()) {
-          DroppedFirstDim = true;
-          continue;
-        }
-      Subscripts.push_back(Expr);
-      continue;
-    }
-
-    auto *ArrayTy = dyn_cast<ArrayType>(Ty);
-    if (!ArrayTy) {
-      Subscripts.clear();
-      Sizes.clear();
-      return false;
-    }
-
-    Subscripts.push_back(Expr);
-    if (!(DroppedFirstDim && i == 2))
-      Sizes.push_back(ArrayTy->getNumElements());
-
-    Ty = ArrayTy->getElementType();
-  }
-  return !Subscripts.empty();
-}
-
 //===----------------------------------------------------------------------===//
 //                   SCEVCallbackVH Class Implementation
 //===----------------------------------------------------------------------===//