reverted the prev commit due to assertion failure

llvm-svn: 273258

2 files changed, 84 insertions, 11 deletions

diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index a46bb3a9b05..44208408b0f 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -866,7 +866,7 @@ static bool isNoWrapAddRec(Value *Ptr, const SCEVAddRecExpr *AR,
 /// \brief Check whether the access through \p Ptr has a constant stride.
 int llvm::getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr,
                        const Loop *Lp, const ValueToValueMap &StridesMap,
-                       bool Assume, bool ShouldCheckWrap) {
+                       bool Assume) {
   Type *Ty = Ptr->getType();
   assert(Ty->isPointerTy() && "Unexpected non-ptr");
 
@@ -905,9 +905,9 @@ int llvm::getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr,
   // to access the pointer value "0" which is undefined behavior in address
   // space 0, therefore we can also vectorize this case.
   bool IsInBoundsGEP = isInBoundsGep(Ptr);
-  bool IsNoWrapAddRec = !ShouldCheckWrap ||
-    PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW) ||
-    isNoWrapAddRec(Ptr, AR, PSE, Lp);
+  bool IsNoWrapAddRec =
+      PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW) ||
+      isNoWrapAddRec(Ptr, AR, PSE, Lp);
   bool IsInAddressSpaceZero = PtrTy->getAddressSpace() == 0;
   if (!IsNoWrapAddRec && !IsInBoundsGEP && !IsInAddressSpaceZero) {
     if (Assume) {
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index e175f7a60ec..954b5938cf5 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2156,13 +2156,87 @@ Value *InnerLoopVectorizer::getStepVector(Value *Val, int StartIdx,
 }
 
 int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
+  assert(Ptr->getType()->isPointerTy() && "Unexpected non-ptr");
+  auto *SE = PSE.getSE();
+  // Make sure that the pointer does not point to structs.
+  if (Ptr->getType()->getPointerElementType()->isAggregateType())
+    return 0;
+
+  // If this value is a pointer induction variable, we know it is consecutive.
+  PHINode *Phi = dyn_cast_or_null<PHINode>(Ptr);
+  if (Phi && Inductions.count(Phi)) {
+    InductionDescriptor II = Inductions[Phi];
+    return II.getConsecutiveDirection();
+  }
+
+  GetElementPtrInst *Gep = getGEPInstruction(Ptr);
+  if (!Gep)
+    return 0;
+
+  unsigned NumOperands = Gep->getNumOperands();
+  Value *GpPtr = Gep->getPointerOperand();
+  // If this GEP value is a consecutive pointer induction variable and all of
+  // the indices are constant, then we know it is consecutive.
+  Phi = dyn_cast<PHINode>(GpPtr);
+  if (Phi && Inductions.count(Phi)) {
+
+    // Make sure that the pointer does not point to structs.
+    PointerType *GepPtrType = cast<PointerType>(GpPtr->getType());
+    if (GepPtrType->getElementType()->isAggregateType())
+      return 0;
+
+    // Make sure that all of the index operands are loop invariant.
+    for (unsigned i = 1; i < NumOperands; ++i)
+      if (!SE->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)), TheLoop))
+        return 0;
+
+    InductionDescriptor II = Inductions[Phi];
+    return II.getConsecutiveDirection();
+  }
+
+  unsigned InductionOperand = getGEPInductionOperand(Gep);
+
+  // Check that all of the gep indices are uniform except for our induction
+  // operand.
+  for (unsigned i = 0; i != NumOperands; ++i)
+    if (i != InductionOperand &&
+        !SE->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)), TheLoop))
+      return 0;
 
-  const ValueToValueMap &Strides = getSymbolicStrides() ? *getSymbolicStrides() :
-    ValueToValueMap();
+  // We can emit wide load/stores only if the last non-zero index is the
+  // induction variable.
+  const SCEV *Last = nullptr;
+  if (!getSymbolicStrides() || !getSymbolicStrides()->count(Gep))
+    Last = PSE.getSCEV(Gep->getOperand(InductionOperand));
+  else {
+    // Because of the multiplication by a stride we can have a s/zext cast.
+    // We are going to replace this stride by 1 so the cast is safe to ignore.
+    //
+    //  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+    //  %0 = trunc i64 %indvars.iv to i32
+    //  %mul = mul i32 %0, %Stride1
+    //  %idxprom = zext i32 %mul to i64  << Safe cast.
+    //  %arrayidx = getelementptr inbounds i32* %B, i64 %idxprom
+    //
+    Last = replaceSymbolicStrideSCEV(PSE, *getSymbolicStrides(),
+                                     Gep->getOperand(InductionOperand), Gep);
+    if (const SCEVCastExpr *C = dyn_cast<SCEVCastExpr>(Last))
+      Last =
+          (C->getSCEVType() == scSignExtend || C->getSCEVType() == scZeroExtend)
+              ? C->getOperand()
+              : Last;
+  }
+  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Last)) {
+    const SCEV *Step = AR->getStepRecurrence(*SE);
+
+    // The memory is consecutive because the last index is consecutive
+    // and all other indices are loop invariant.
+    if (Step->isOne())
+      return 1;
+    if (Step->isAllOnesValue())
+      return -1;
+  }
 
-  int Stride = getPtrStride(PSE, Ptr, TheLoop, Strides, true, false);
-  if (Stride == 1 || Stride == -1)
-    return Stride;
   return 0;
 }
 
@@ -2543,8 +2617,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
       Ptr = Builder.Insert(Gep2);
     } else { // No GEP
       // Use the induction element ptr.
-      assert(isa<SCEVAddRecExpr>(PSE.getSE()->getSCEV(Ptr)) &&
-             "Invalid induction ptr");
+      assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
       setDebugLocFromInst(Builder, Ptr);
       VectorParts &PtrVal = getVectorValue(Ptr);
       Ptr = Builder.CreateExtractElement(PtrVal[0], Zero);