From 4c58b2761a73b962631a6405c66fc14835cb62c6 Mon Sep 17 00:00:00 2001
From: Elena Demikhovsky <elena.demikhovsky@intel.com>
Date: Mon, 27 Jun 2016 11:19:23 +0000
Subject: Fixed consecutive memory access detection in Loop Vectorizer. It did
 not handle correctly cases without GEP.

The following loop wasn't vectorized:

for (int i=0; i<len; i++)

  *to++ = *from++;

I use getPtrStride() to find Stride for memory access and return 0 is the Stride is not 1 or -1.

Re-commit rL273257 - revision: http://reviews.llvm.org/D20789

llvm-svn: 273864
---
 llvm/lib/Analysis/LoopAccessAnalysis.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

(limited to 'llvm/lib/Analysis/LoopAccessAnalysis.cpp')

diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 27f5b12b4ca..6ba054c1e4d 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 Assume, bool ShouldCheckWrap) {
   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 =
-      PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW) ||
-      isNoWrapAddRec(Ptr, AR, PSE, Lp);
+  bool IsNoWrapAddRec = !ShouldCheckWrap ||
+    PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW) ||
+    isNoWrapAddRec(Ptr, AR, PSE, Lp);
   bool IsInAddressSpaceZero = PtrTy->getAddressSpace() == 0;
   if (!IsNoWrapAddRec && !IsInBoundsGEP && !IsInAddressSpaceZero) {
     if (Assume) {
-- 
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