Vendor import of llvm r114020 (from the release_28 branch):vendor/llvm/llvm-r114020

http://llvm.org/svn/llvm-project/llvm/branches/release_28@114020

Approved by:	rpaulo (mentor)

1 files changed, 43 insertions, 31 deletions

diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index d4a4b26e25ec..66a06aeac43c 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -647,6 +647,11 @@ public:
 
   bool operator()(std::pair<const Loop *, const SCEV *> LHS,
                   std::pair<const Loop *, const SCEV *> RHS) const {
+    // Keep pointer operands sorted at the end.
+    if (LHS.second->getType()->isPointerTy() !=
+        RHS.second->getType()->isPointerTy())
+      return LHS.second->getType()->isPointerTy();
+
     // Compare loops with PickMostRelevantLoop.
     if (LHS.first != RHS.first)
       return PickMostRelevantLoop(LHS.first, RHS.first, DT) != LHS.first;
@@ -699,8 +704,15 @@ Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
       // The running sum expression is a pointer. Try to form a getelementptr
       // at this level with that as the base.
       SmallVector<const SCEV *, 4> NewOps;
-      for (; I != E && I->first == CurLoop; ++I)
-        NewOps.push_back(I->second);
+      for (; I != E && I->first == CurLoop; ++I) {
+        // If the operand is SCEVUnknown and not instructions, peek through
+        // it, to enable more of it to be folded into the GEP.
+        const SCEV *X = I->second;
+        if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(X))
+          if (!isa<Instruction>(U->getValue()))
+            X = SE.getSCEV(U->getValue());
+        NewOps.push_back(X);
+      }
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, Sum);
     } else if (const PointerType *PTy = dyn_cast<PointerType>(Op->getType())) {
       // The running sum is an integer, and there's a pointer at this level.
@@ -1047,9 +1059,7 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
   // First check for an existing canonical IV in a suitable type.
   PHINode *CanonicalIV = 0;
   if (PHINode *PN = L->getCanonicalInductionVariable())
-    if (SE.isSCEVable(PN->getType()) &&
-        SE.getEffectiveSCEVType(PN->getType())->isIntegerTy() &&
-        SE.getTypeSizeInBits(PN->getType()) >= SE.getTypeSizeInBits(Ty))
+    if (SE.getTypeSizeInBits(PN->getType()) >= SE.getTypeSizeInBits(Ty))
       CanonicalIV = PN;
 
   // Rewrite an AddRec in terms of the canonical induction variable, if
@@ -1102,21 +1112,13 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
                                 SE.getUnknown(expand(Rest))));
   }
 
-  // {0,+,1} --> Insert a canonical induction variable into the loop!
-  if (S->isAffine() && S->getOperand(1)->isOne()) {
-    // If there's a canonical IV, just use it.
-    if (CanonicalIV) {
-      assert(Ty == SE.getEffectiveSCEVType(CanonicalIV->getType()) &&
-             "IVs with types different from the canonical IV should "
-             "already have been handled!");
-      return CanonicalIV;
-    }
-
+  // If we don't yet have a canonical IV, create one.
+  if (!CanonicalIV) {
     // Create and insert the PHI node for the induction variable in the
     // specified loop.
     BasicBlock *Header = L->getHeader();
-    PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
-    rememberInstruction(PN);
+    CanonicalIV = PHINode::Create(Ty, "indvar", Header->begin());
+    rememberInstruction(CanonicalIV);
 
     Constant *One = ConstantInt::get(Ty, 1);
     for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
@@ -1125,40 +1127,45 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
       if (L->contains(HP)) {
         // Insert a unit add instruction right before the terminator
         // corresponding to the back-edge.
-        Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
-                                                           HP->getTerminator());
+        Instruction *Add = BinaryOperator::CreateAdd(CanonicalIV, One,
+                                                     "indvar.next",
+                                                     HP->getTerminator());
         rememberInstruction(Add);
-        PN->addIncoming(Add, HP);
+        CanonicalIV->addIncoming(Add, HP);
       } else {
-        PN->addIncoming(Constant::getNullValue(Ty), HP);
+        CanonicalIV->addIncoming(Constant::getNullValue(Ty), HP);
       }
     }
   }
 
+  // {0,+,1} --> Insert a canonical induction variable into the loop!
+  if (S->isAffine() && S->getOperand(1)->isOne()) {
+    assert(Ty == SE.getEffectiveSCEVType(CanonicalIV->getType()) &&
+           "IVs with types different from the canonical IV should "
+           "already have been handled!");
+    return CanonicalIV;
+  }
+
   // {0,+,F} --> {0,+,1} * F
-  // Get the canonical induction variable I for this loop.
-  Value *I = CanonicalIV ?
-             CanonicalIV :
-             getOrInsertCanonicalInductionVariable(L, Ty);
 
   // If this is a simple linear addrec, emit it now as a special case.
   if (S->isAffine())    // {0,+,F} --> i*F
     return
       expand(SE.getTruncateOrNoop(
-        SE.getMulExpr(SE.getUnknown(I),
+        SE.getMulExpr(SE.getUnknown(CanonicalIV),
                       SE.getNoopOrAnyExtend(S->getOperand(1),
-                                            I->getType())),
+                                            CanonicalIV->getType())),
         Ty));
 
   // If this is a chain of recurrences, turn it into a closed form, using the
   // folders, then expandCodeFor the closed form.  This allows the folders to
   // simplify the expression without having to build a bunch of special code
   // into this folder.
-  const SCEV *IH = SE.getUnknown(I);   // Get I as a "symbolic" SCEV.
+  const SCEV *IH = SE.getUnknown(CanonicalIV);   // Get I as a "symbolic" SCEV.
 
   // Promote S up to the canonical IV type, if the cast is foldable.
   const SCEV *NewS = S;
-  const SCEV *Ext = SE.getNoopOrAnyExtend(S, I->getType());
+  const SCEV *Ext = SE.getNoopOrAnyExtend(S, CanonicalIV->getType());
   if (isa<SCEVAddRecExpr>(Ext))
     NewS = Ext;
 
@@ -1337,16 +1344,21 @@ void SCEVExpander::restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I) {
 /// canonical induction variable of the specified type for the specified
 /// loop (inserting one if there is none).  A canonical induction variable
 /// starts at zero and steps by one on each iteration.
-Value *
+PHINode *
 SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L,
                                                     const Type *Ty) {
   assert(Ty->isIntegerTy() && "Can only insert integer induction variables!");
+
+  // Build a SCEV for {0,+,1}<L>.
   const SCEV *H = SE.getAddRecExpr(SE.getConstant(Ty, 0),
                                    SE.getConstant(Ty, 1), L);
+
+  // Emit code for it.
   BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
   BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
-  Value *V = expandCodeFor(H, 0, L->getHeader()->begin());
+  PHINode *V = cast<PHINode>(expandCodeFor(H, 0, L->getHeader()->begin()));
   if (SaveInsertBB)
     restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
   return V;
 }