Reinstate r273711

r273711 was reverted by r273743.  The inliner needs to know about any
call sites in the inlined function.  These were obscured if we replaced
a call to undef with an undef but kept the call around.

This fixes PR28298.

llvm-svn: 273753

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 6ff05fe3e59..fcdb45b6611 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -296,9 +296,11 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
         if (Value *MappedV = VMap.lookup(V))
           V = MappedV;
 
-        VMap[&*II] = V;
-        delete NewInst;
-        continue;
+        if (!NewInst->mayHaveSideEffects()) {
+          VMap[&*II] = V;
+          delete NewInst;
+          continue;
+        }
       }
     }