We may visit a call that uses an alloca multiple times in callUsesLocalStack, sometimes with IsNocapture true and sometimes with IsNocapture false. We accidentally skipped work we needed to do in the IsNocapture=false case if we were called with IsNocapture=true the first time. Fixes PR20405!

llvm-svn: 213726

1 files changed, 3 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 05b9892470b..b7580255150 100644
--- a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -227,12 +227,10 @@ struct AllocaDerivedValueTracker {
   }
 
   void callUsesLocalStack(CallSite CS, bool IsNocapture) {
-    // Add it to the list of alloca users. If it's already there, skip further
-    // processing.
-    if (!AllocaUsers.insert(CS.getInstruction()))
-      return;
+    // Add it to the list of alloca users.
+    AllocaUsers.insert(CS.getInstruction());
 
-    // If it's nocapture then it can't capture the alloca.
+    // If it's nocapture then it can't capture this alloca.
     if (IsNocapture)
       return;