Factor out some of the code for updating old SCEVUnknown values, and

extend it to handle the case where multiple RAUWs affect a single
SCEVUnknown.

Add a ScalarEvolution unittest to test for this situation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109705 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 1b27efb995..b052a82232 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -386,6 +386,11 @@ namespace llvm {
     bool isKnownPredicateWithRanges(ICmpInst::Predicate Pred,
                                     const SCEV *LHS, const SCEV *RHS);
 
+    /// forgetSCEVUnknown - V is being deleted or RAUW'd; remove the
+    /// SCEVUnknown for it from the uniquing map, and optionally
+    /// clear its contents to point to a replacement value.
+    void forgetSCEVUnknown(Value *V, Value *NewV);
+
   public:
     static char ID; // Pass identification, replacement for typeid
     ScalarEvolution();