Add a lint check for indirectbr with no successors.

[oota-llvm.git] / lib / Analysis / ScalarEvolutionExpander.cpp

diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 6017c51fc634c2f695dd41aa4ac743b90113a288..66a06aeac43cace80d8c47e36a668d27f5f9479f 100644 (file)
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1059,9 +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
@@ -1114,21 +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);
@@ -1137,40 +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;
 
@@ -1353,12 +1348,17 @@ 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();
   PHINode *V = cast<PHINode>(expandCodeFor(H, 0, L->getHeader()->begin()));
   if (SaveInsertBB)
     restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
   return V;
 }