Revert 94937 and move the noreturn check to codegen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95198 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/TailRecursionElimination.cpp b/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 913dd73..162d902 100644
--- a/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -184,11 +184,10 @@
   if (!FunctionContainsEscapingAllocas)
     for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
       for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
-        if (CallInst *CI = dyn_cast<CallInst>(I))
-          if (!CI->doesNotReturn()) {
-            CI->setTailCall();
-            MadeChange = true;
-          }
+        if (CallInst *CI = dyn_cast<CallInst>(I)) {
+          CI->setTailCall();
+          MadeChange = true;
+        }
 
   return MadeChange;
 }