Address two correctness issues in LoadStoreVectorizer

Summary:
GetBoundryInstruction returns the last instruction as the instruction which follows or end(). Otherwise the last instruction in the boundry set is not being tested by isVectorizable().
Partially solve reordering of instructions. More extensive solution to follow.

Reviewers: tstellarAMD, llvm-commits, jlebar

Subscribers: escha, arsenm, mzolotukhin

Differential Revision: http://reviews.llvm.org/D21934

llvm-svn: 274389

1 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
index f24628eb2f5..2f8a470b4c0 100644
--- a/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -331,6 +331,7 @@ bool Vectorizer::isConsecutiveAccess(Value *A, Value *B) {
 }
 
 void Vectorizer::reorder(Instruction *I) {
+  Instruction *InsertAfter = I;
   for (User *U : I->users()) {
     Instruction *User = dyn_cast<Instruction>(U);
     if (!User || User->getOpcode() == Instruction::PHI)
@@ -338,7 +339,8 @@ void Vectorizer::reorder(Instruction *I) {
 
     if (!DT.dominates(I, User)) {
       User->removeFromParent();
-      User->insertAfter(I);
+      User->insertAfter(InsertAfter);
+      InsertAfter = User;
       reorder(User);
     }
   }
@@ -359,13 +361,15 @@ Vectorizer::getBoundaryInstrs(ArrayRef<Value *> Chain) {
     ++NumFound;
     if (NumFound == 1) {
       FirstInstr = I.getIterator();
-    } else if (NumFound == Chain.size()) {
+    }
+    if (NumFound == Chain.size()) {
       LastInstr = I.getIterator();
       break;
     }
   }
 
-  return std::make_pair(FirstInstr, LastInstr);
+  // Range is [first, last).
+  return std::make_pair(FirstInstr, ++LastInstr);
 }
 
 void Vectorizer::eraseInstructions(ArrayRef<Value *> Chain) {
@@ -415,6 +419,9 @@ bool Vectorizer::isVectorizable(ArrayRef<Value *> Chain,
     }
   }
 
+  assert(Chain.size() == ChainInstrs.size() &&
+         "All instructions in the Chain must exist in [From, To).");
+
   for (auto EntryMem : MemoryInstrs) {
     Value *V = EntryMem.first;
     unsigned VIdx = EntryMem.second;