Change SCEVExpander's expandCodeFor to provide more flexibility
with the persistent insertion point, and change IndVars to make
use of it. This fixes a bug where IndVars was holding on to a
stale insertion point and forcing the SCEVExpander to continue to
use it.

This fixes PR4038.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69892 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 80b47d8..9676ea2 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -332,12 +332,10 @@
   return LHS;
 }
 
-Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty,
-                                   BasicBlock::iterator IP) {
+Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty) {
   // Expand the code for this SCEV.
   assert(SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(SH->getType()) &&
          "non-trivial casts should be done with the SCEVs directly!");
-  InsertPt = IP;
   Value *V = expand(SH);
   return InsertNoopCastOfTo(V, Ty);
 }