Revert "Cleanup some SCEV logic a bit."

This reverts commit 82cd8f7382322bee7a71cdc31f7a923c44d37d32.

Just add a comment instead!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177377 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index f01af001ca9da6aa59cd462bdcbd7196def457d9..9562cf8d5dcce1e6514b036e901e8d7672d49158 100644 (file)
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2716,11 +2716,11 @@ void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter,
   // by LSR.
   const IVInc &Head = Chain.Incs[0];
   User::op_iterator IVOpEnd = Head.UserInst->op_end();
+  // findIVOperand returns IVOpEnd if it can no longer find a valid IV user.
   User::op_iterator IVOpIter = findIVOperand(Head.UserInst->op_begin(),
                                              IVOpEnd, L, SE);
-  assert(IVOpIter != IVOpEnd && "No IV operands found");
   Value *IVSrc = 0;
-  do {
+  while (IVOpIter != IVOpEnd) {
     IVSrc = getWideOperand(*IVOpIter);
 
     // If this operand computes the expression that the chain needs, we may use
@@ -2736,8 +2736,7 @@ void LSRInstance::GenerateIVChain(const IVChain &Chain, SCEVExpander &Rewriter,
       break;
     }
     IVOpIter = findIVOperand(llvm::next(IVOpIter), IVOpEnd, L, SE);
-  } while (IVOpIter != IVOpEnd);
-
+  }
   if (IVOpIter == IVOpEnd) {
     // Gracefully give up on this chain.
     DEBUG(dbgs() << "Concealed chain head: " << *Head.UserInst << "\n");