Index: llvm/lib/Transforms/IPO/FunctionAttrs.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -445,6 +445,10 @@
   if (A->hasInAllocaAttr())
     return Attribute::None;
 
+  // If the argument is WriteOnly, no read-attribute should be added.
+  if (A->hasAttribute(Attribute::WriteOnly))
+    return Attribute::None;
+
   bool IsRead = false;
   // We don't need to track IsWritten. If A is written to, return immediately.
 
Index: llvm/test/Transforms/FunctionAttrs/writeonly.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/FunctionAttrs/writeonly.ll
@@ -0,0 +1,16 @@
+; RUN: opt < %s -O1 -S | FileCheck %s
+; RUN: opt < %s -O2 -S | FileCheck %s
+; RUN: opt < %s -O3 -S | FileCheck %s
+
+%_type = type <{ i8*, i8, i8, i8, i8 }>
+
+@d = internal global %_type <{ i8* null, i8 1, i8 13, i8 0, i8 -127 }>, align 8
+
+; CHECK: define void @foo(i32* nocapture writeonly %.aaa)
+define void @foo(i32* writeonly %.aaa) {
+foo_entry:
+  %_param_.aaa = alloca i32*, align 8
+  store i32* %.aaa, i32** %_param_.aaa, align 8
+  store i8 0, i8* getelementptr inbounds (%_type, %_type* @d, i32 0, i32 3)
+  ret void
+}