diff --git a/llvm/include/llvm/IR/Function.h b/llvm/include/llvm/IR/Function.h
--- a/llvm/include/llvm/IR/Function.h
+++ b/llvm/include/llvm/IR/Function.h
@@ -498,7 +498,12 @@
 
   /// Determine if the function does not access or only writes memory.
   bool doesNotReadMemory() const {
-    return doesNotAccessMemory() || hasFnAttribute(Attribute::WriteOnly);
+    return doesNotAccessMemory() || hasFnAttribute(Attribute::WriteOnly) ||
+           (hasFnAttribute(Attribute::ArgMemOnly) &&
+            all_of(args(), [](const Argument &A) {
+              return !A.getType()->isPointerTy() ||
+                     A.hasAttribute(Attribute::WriteOnly);
+            }));
   }
   void setDoesNotReadMemory() {
     addFnAttr(Attribute::WriteOnly);
diff --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -1673,7 +1673,8 @@
 
   /// Determine if the call does not access or only writes memory.
   bool doesNotReadMemory() const {
-    return doesNotAccessMemory() || hasFnAttr(Attribute::WriteOnly);
+    return doesNotAccessMemory() || hasFnAttr(Attribute::WriteOnly) ||
+           (onlyAccessesArgMemory() && argsWriteOnly());
   }
   void setDoesNotReadMemory() {
     addAttribute(AttributeList::FunctionIndex, Attribute::WriteOnly);
@@ -2146,6 +2147,14 @@
 
     return hasFnAttrOnCalledFunction(Kind);
   }
+
+  bool argsWriteOnly() const {
+    for (unsigned I = 0; I < getNumArgOperands(); I++)
+      if (getArgOperand(I)->getType()->isPointerTy() &&
+          !paramHasAttr(I, Attribute::WriteOnly))
+        return false;
+    return true;
+  }
 };
 
 template <>
diff --git a/llvm/test/Transforms/Attributor/readattrs.ll b/llvm/test/Transforms/Attributor/readattrs.ll
--- a/llvm/test/Transforms/Attributor/readattrs.ll
+++ b/llvm/test/Transforms/Attributor/readattrs.ll
@@ -93,8 +93,7 @@
 
 ; ATTRIBUTOR: declare <4 x i32> @test11_1
 declare <4 x i32> @test11_1(<4 x i32*>) argmemonly nounwind readonly
-; ATTRIBUTOR: readonly
-; ATTRIBUTOR-NOT: readnone
+; ATTRIBUTOR: readnone
 ; ATTRIBUTOR: define <4 x i32> @test11_2
 define <4 x i32> @test11_2(<4 x i32*> %ptrs) {
   %res = call <4 x i32> @test11_1(<4 x i32*> %ptrs)