From f291ab2fbaa5ed1cfa20ca47e8dece1040a5065b Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Tue, 1 Mar 2011 00:33:47 +0000
Subject: Add an obvious missing safety check to
 DAE::RemoveDeadArgumentsFromCallers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126720 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/DeadArgumentElimination.cpp |  2 +-
 test/Transforms/DeadArgElim/deadexternal.ll    | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/Transforms/IPO/DeadArgumentElimination.cpp b/lib/Transforms/IPO/DeadArgumentElimination.cpp
index b423221..4d1f7ab 100644
--- a/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -294,7 +294,7 @@ bool DAE::DeleteDeadVarargs(Function &Fn) {
 /// instead.
 bool DAE::RemoveDeadArgumentsFromCallers(Function &Fn)
 {
-  if (Fn.isDeclaration())
+  if (Fn.isDeclaration() || Fn.mayBeOverridden())
     return false;
 
   // Functions with local linkage should already have been handled.
diff --git a/test/Transforms/DeadArgElim/deadexternal.ll b/test/Transforms/DeadArgElim/deadexternal.ll
index 5a80aba..8409261 100644
--- a/test/Transforms/DeadArgElim/deadexternal.ll
+++ b/test/Transforms/DeadArgElim/deadexternal.ll
@@ -37,3 +37,16 @@ entry:
   call void @f(i32 %tmp)
   ret void
 }
+
+; Check that callers are not transformed for weak definitions.
+define weak i32 @weak_f(i32 %x) nounwind {
+entry:
+  ret i32 0
+}
+define void @weak_f_caller() nounwind {
+entry:
+; CHECK: call i32 @weak_f(i32 10)
+  %call = tail call i32 @weak_f(i32 10)
+  ret void
+}
+
-- 
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