Fix PR2411, where ip constant prop would propagate the

result of a weak function.

llvm-svn: 52137

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp b/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
index 792fa980a60..4ebdaf3fb2b 100644
--- a/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
+++ b/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
@@ -147,6 +147,11 @@ bool IPCP::PropagateConstantReturn(Function &F) {
   if (F.getReturnType() == Type::VoidTy)
     return false; // No return value.
 
+  // If this function could be overridden later in the link stage, we can't
+  // propagate information about its results into callers.
+  if (F.hasLinkOnceLinkage() || F.hasWeakLinkage())
+    return false;
+  
   // Check to see if this function returns a constant.
   SmallVector<Value *,4> RetVals;
   const StructType *STy = dyn_cast<StructType>(F.getReturnType());