Various comment and whitespace cleanups.

llvm-svn: 79533

llvm/include/llvm/Analysis/ScalarEvolutionExpander.h

@@ -24,7 +24,7 @@ namespace llvm {
   /// rewrite expressions in canonical form.
   ///
   /// Clients should create an instance of this class when rewriting is needed,
-  /// and destroy it when finished to allow the release of the associated 
+  /// and destroy it when finished to allow the release of the associated
   /// memory.
   struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
     ScalarEvolution &SE;
@@ -62,7 +62,7 @@ namespace llvm {
 
   private:
     LLVMContext &getContext() const { return SE.getContext(); }
-    
+
     /// InsertBinop - Insert the specified binary operator, doing a small amount
     /// of work to avoid inserting an obviously redundant operation.
     Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS);
@@ -126,4 +126,3 @@ namespace llvm {
 }
 
 #endif
-

llvm/lib/Analysis/ConstantFolding.cpp

@@ -208,7 +208,7 @@ static Constant *SymbolicallyEvaluateGEP(Constant* const* Ops, unsigned NumOps,
          "Computed GetElementPtr has unexpected type!");
 
   // If we ended up indexing a member with a type that doesn't match
-  // type type of what the original indices indexed, add a cast.
+  // the type of what the original indices indexed, add a cast.
   if (Ty != cast<PointerType>(ResultTy)->getElementType())
     C = ConstantExpr::getBitCast(C, ResultTy);
 

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -1682,7 +1682,7 @@ const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS,
 
   if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
     if (RHSC->getValue()->equalsInt(1))
-      return LHS;                            // X udiv 1 --> x
+      return LHS;                               // X udiv 1 --> x
     if (RHSC->isZero())
       return getIntegerSCEV(0, LHS->getType()); // value is undefined
 
@@ -3533,8 +3533,8 @@ ScalarEvolution::ComputeBackedgeTakenCountFromExitCondICmp(const Loop *L,
     if (!isa<SCEVCouldNotCompute>(TC)) return TC;
     break;
   }
-  case ICmpInst::ICMP_EQ: {
+  case ICmpInst::ICMP_EQ: {                     // while (X == Y)
-    // Convert to: while (X-Y == 0)           // while (X == Y)
+    // Convert to: while (X-Y == 0)
     const SCEV *TC = HowFarToNonZero(getMinusSCEV(LHS, RHS), L);
     if (!isa<SCEVCouldNotCompute>(TC)) return TC;
     break;
@@ -3986,7 +3986,7 @@ const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) {
                                               getContext());
         else
           C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
-                                       &Operands[0], Operands.size(), 
+                                       &Operands[0], Operands.size(),
                                        getContext());
         Pair.first->second = C;
         return getSCEV(C);
@@ -4235,7 +4235,7 @@ const SCEV *ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
 
       // First, handle unitary steps.
       if (StepC->getValue()->equalsInt(1))      // 1*N = -Start (mod 2^BW), so:
-        return getNegativeSCEV(Start);       //   N = -Start (as unsigned)
+        return getNegativeSCEV(Start);          //   N = -Start (as unsigned)
       if (StepC->getValue()->isAllOnesValue())  // -1*N = -Start (mod 2^BW), so:
         return Start;                           //    N = Start (as unsigned)
 

llvm/lib/Analysis/ScalarEvolutionExpander.cpp

@@ -53,10 +53,9 @@ Value *SCEVExpander::InsertNoopCastOfTo(Value *V, const Type *Ty) {
         return CE->getOperand(0);
   }
 
-  // FIXME: keep track of the cast instruction.
   if (Constant *C = dyn_cast<Constant>(V))
     return ConstantExpr::getCast(Op, C, Ty);
-  
+
   if (Argument *A = dyn_cast<Argument>(V)) {
     // Check to see if there is already a cast!
     for (Value::use_iterator UI = A->use_begin(), E = A->use_end();
@@ -317,13 +316,17 @@ static void SplitAddRecs(SmallVectorImpl<const SCEV *> &Ops,
   }
 }
 
-/// expandAddToGEP - Expand a SCEVAddExpr with a pointer type into a GEP
+/// expandAddToGEP - Expand an addition expression with a pointer type into
-/// instead of using ptrtoint+arithmetic+inttoptr. This helps
+/// a GEP instead of using ptrtoint+arithmetic+inttoptr. This helps
-/// BasicAliasAnalysis and other passes analyze the result.
+/// BasicAliasAnalysis and other passes analyze the result. See the rules
+/// for getelementptr vs. inttoptr in
+/// http://llvm.org/docs/LangRef.html#pointeraliasing
+/// for details.
 ///
-/// Design note: This depends on ScalarEvolution not recognizing inttoptr
+/// Design note: The correctness of using getelmeentptr here depends on
-/// and ptrtoint operators, as they may introduce pointer arithmetic
+/// ScalarEvolution not recognizing inttoptr and ptrtoint operators, as
-/// which may not be safely converted into getelementptr.
+/// they may introduce pointer arithmetic which may not be safely converted
+/// into getelementptr.
 ///
 /// Design note: It might seem desirable for this function to be more
 /// loop-aware. If some of the indices are loop-invariant while others