1 files changed, 24 insertions, 34 deletions

diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 489396c460b..96acda3f45c 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -3188,27 +3188,24 @@ DependenceAnalysis::tryDelinearize(const SCEV *SrcSCEV, const SCEV *DstSCEV,
   if (!SrcAR || !DstAR || !SrcAR->isAffine() || !DstAR->isAffine())
     return false;
 
-  SmallVector<const SCEV *, 4> SrcSubscripts, DstSubscripts, SrcSizes, DstSizes;
-  const SCEV *RemainderS = SrcAR->delinearize(*SE, SrcSubscripts, SrcSizes);
-  const SCEV *RemainderD = DstAR->delinearize(*SE, DstSubscripts, DstSizes);
+  // First step: collect parametric terms in both array references.
+  SmallVector<const SCEV *, 4> Terms;
+  SrcAR->collectParametricTerms(*SE, Terms);
+  DstAR->collectParametricTerms(*SE, Terms);
 
-  int size = SrcSubscripts.size();
-  // Fail when there is only a subscript: that's a linearized access function.
-  if (size < 2)
-    return false;
+  // Second step: find subscript sizes.
+  SmallVector<const SCEV *, 4> Sizes;
+  SrcAR->findArrayDimensions(*SE, Terms, Sizes);
 
-  int dstSize = DstSubscripts.size();
-  // Fail when the number of subscripts in Src and Dst differ.
-  if (size != dstSize)
-    return false;
+  // Third step: compute the access functions for each subscript.
+  SmallVector<const SCEV *, 4> SrcSubscripts, DstSubscripts;
+  const SCEV *RemainderS = SrcAR->computeAccessFunctions(*SE, SrcSubscripts, Sizes);
+  const SCEV *RemainderD = DstAR->computeAccessFunctions(*SE, DstSubscripts, Sizes);
 
-  // Fail when the size of any of the subscripts in Src and Dst differs: the
-  // dependence analysis assumes that elements in the same array have same size.
-  // SCEV delinearization does not have a context based on which it would decide
-  // globally the size of subscripts that would best fit all the array accesses.
-  for (int i = 0; i < size; ++i)
-    if (SrcSizes[i] != DstSizes[i])
-      return false;
+  // Fail when there is only a subscript: that's a linearized access function.
+  if (SrcSubscripts.size() < 2 || DstSubscripts.size() < 2 ||
+      SrcSubscripts.size() != DstSubscripts.size())
+    return false;
 
   // When the difference in remainders is different than a constant it might be
   // that the base address of the arrays is not the same.
@@ -3216,23 +3213,16 @@ DependenceAnalysis::tryDelinearize(const SCEV *SrcSCEV, const SCEV *DstSCEV,
   if (!isa<SCEVConstant>(DiffRemainders))
     return false;
 
-  // Normalize the last dimension: integrate the size of the "scalar dimension"
-  // and the remainder of the delinearization.
-  DstSubscripts[size-1] = SE->getMulExpr(DstSubscripts[size-1],
-                                         DstSizes[size-1]);
-  SrcSubscripts[size-1] = SE->getMulExpr(SrcSubscripts[size-1],
-                                         SrcSizes[size-1]);
-  SrcSubscripts[size-1] = SE->getAddExpr(SrcSubscripts[size-1], RemainderS);
-  DstSubscripts[size-1] = SE->getAddExpr(DstSubscripts[size-1], RemainderD);
+  int size = SrcSubscripts.size();
 
-#ifndef NDEBUG
-  DEBUG(errs() << "\nSrcSubscripts: ");
-  for (int i = 0; i < size; i++)
-    DEBUG(errs() << *SrcSubscripts[i]);
-  DEBUG(errs() << "\nDstSubscripts: ");
-  for (int i = 0; i < size; i++)
-    DEBUG(errs() << *DstSubscripts[i]);
-#endif
+  DEBUG({
+      dbgs() << "\nSrcSubscripts: ";
+    for (int i = 0; i < size; i++)
+      dbgs() << *SrcSubscripts[i];
+    dbgs() << "\nDstSubscripts: ";
+    for (int i = 0; i < size; i++)
+      dbgs() << *DstSubscripts[i];
+    });
 
   // The delinearization transforms a single-subscript MIV dependence test into
   // a multi-subscript SIV dependence test that is easier to compute. So we