Fix typo

[oota-llvm.git] / lib / Transforms / Vectorize / SLPVectorizer.cpp

diff --git a/lib/Transforms/Vectorize/SLPVectorizer.cpp b/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 9312b4bb4b07f914fd95585c55d8e8dea96f5932..73e80565f4dd2c55495dd1436e6943d34e7e238b 100644 (file)
--- a/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -75,8 +75,8 @@ private:
   DebugLoc DbgLoc;
 };
 
-/// A helper class for numbering instructions in multible blocks.
-/// Numbers starts at zero for each basic block.
+/// A helper class for numbering instructions in multiple blocks.
+/// Numbers start at zero for each basic block.
 struct BlockNumbering {
 
   BlockNumbering(BasicBlock *Bb) : BB(Bb), Valid(false) {}
@@ -308,7 +308,7 @@ private:
   /// \returns the index of the last instrucion in the BB from \p VL.
   int getLastIndex(ArrayRef<Value *> VL);
 
-  /// \returns the Instrucion in the bundle \p VL.
+  /// \returns the Instruction in the bundle \p VL.
   Instruction *getLastInstruction(ArrayRef<Value *> VL);
 
   /// \returns a vector from a collection of scalars in \p VL.
@@ -1187,10 +1187,21 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
       PHINode *NewPhi = Builder.CreatePHI(VecTy, PH->getNumIncomingValues());
       E->VectorizedValue = NewPhi;
 
+      // PHINodes may have multiple entries from the same block. We want to
+      // visit every block once.
+      SmallSet<BasicBlock*, 4> VisitedBBs;
+
       for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
         ValueList Operands;
         BasicBlock *IBB = PH->getIncomingBlock(i);
 
+        if (VisitedBBs.count(IBB)) {
+          NewPhi->addIncoming(NewPhi->getIncomingValueForBlock(IBB), IBB);
+          continue;
+        }
+
+        VisitedBBs.insert(IBB);
+
         // Prepare the operand vector.
         for (unsigned j = 0; j < E->Scalars.size(); ++j)
           Operands.push_back(cast<PHINode>(E->Scalars[j])->
@@ -1864,6 +1875,8 @@ bool SLPVectorizer::tryToVectorize(BinaryOperator *V, BoUpSLP &R) {
 bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
   bool Changed = false;
   SmallVector<Value *, 4> Incoming;
+  SmallSet<Instruction *, 16> VisitedInstrs;
+
   // Collect the incoming values from the PHIs.
   for (BasicBlock::iterator instr = BB->begin(), ie = BB->end(); instr != ie;
        ++instr) {
@@ -1872,9 +1885,21 @@ bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
     if (!P)
       break;
 
+    // We may go through BB multiple times so skip the one we have checked.
+    if (VisitedInstrs.count(instr))
+      continue;
+    VisitedInstrs.insert(instr);
+
     // Stop constructing the list when you reach a different type.
     if (Incoming.size() && P->getType() != Incoming[0]->getType()) {
-      Changed |= tryToVectorizeList(Incoming, R);
+      if (tryToVectorizeList(Incoming, R)) {
+        // We would like to start over since some instructions are deleted
+        // and the iterator may become invalid value.
+        Changed = true;
+        instr = BB->begin();
+        ie = BB->end();
+      }
+
       Incoming.clear();
     }
 
@@ -1884,7 +1909,15 @@ bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
   if (Incoming.size() > 1)
     Changed |= tryToVectorizeList(Incoming, R);
 
-  for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
+  VisitedInstrs.clear();
+
+  for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; it++) {
+
+    // We may go through BB multiple times so skip the one we have checked.
+    if (VisitedInstrs.count(it))
+      continue;
+    VisitedInstrs.insert(it);
+
     if (isa<DbgInfoIntrinsic>(it))
       continue;
 
@@ -1906,20 +1939,38 @@ bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
       if (Inst == P)
         Inst = BI->getOperand(1);
 
-      Changed |= tryToVectorize(dyn_cast<BinaryOperator>(Inst), R);
+      if (tryToVectorize(dyn_cast<BinaryOperator>(Inst), R)) {
+        // We would like to start over since some instructions are deleted
+        // and the iterator may become invalid value.
+        Changed = true;
+        it = BB->begin();
+        e = BB->end();
+      }
       continue;
     }
 
     // Try to vectorize trees that start at compare instructions.
     if (CmpInst *CI = dyn_cast<CmpInst>(it)) {
       if (tryToVectorizePair(CI->getOperand(0), CI->getOperand(1), R)) {
-        Changed |= true;
+        Changed = true;
+        // We would like to start over since some instructions are deleted
+        // and the iterator may become invalid value.
+        it = BB->begin();
+        e = BB->end();
         continue;
       }
-      for (int i = 0; i < 2; ++i)
-        if (BinaryOperator *BI = dyn_cast<BinaryOperator>(CI->getOperand(i)))
-          Changed |=
-              tryToVectorizePair(BI->getOperand(0), BI->getOperand(1), R);
+
+      for (int i = 0; i < 2; ++i) {
+         if (BinaryOperator *BI = dyn_cast<BinaryOperator>(CI->getOperand(i))) {
+            if (tryToVectorizePair(BI->getOperand(0), BI->getOperand(1), R)) {
+              Changed = true;
+              // We would like to start over since some instructions are deleted
+              // and the iterator may become invalid value.
+              it = BB->begin();
+              e = BB->end();
+            }
+         }
+      }
       continue;
     }
   }