[FuncAttrs] Remove "access range attributes" for read-none functions

The presence of readnone and an access range attribute (argmemonly,
inaccessiblememonly, inaccessiblemem_or_argmemonly) is considered an
error by the verifier. This seems strict but also not wrong. This
patch makes sure function attribute detection will remove all access
range attributes for readnone functions.

llvm-svn: 341927

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index d40ee30f453..72c850fca99 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -281,6 +281,13 @@ static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
     F->removeFnAttr(Attribute::ReadNone);
     F->removeFnAttr(Attribute::WriteOnly);
 
+    if (!WritesMemory && !ReadsMemory) {
+      // Clear out any "access range attributes" if readnone was deduced.
+      F->removeFnAttr(Attribute::ArgMemOnly);
+      F->removeFnAttr(Attribute::InaccessibleMemOnly);
+      F->removeFnAttr(Attribute::InaccessibleMemOrArgMemOnly);
+    }
+
     // Add in the new attribute.
     if (WritesMemory && !ReadsMemory)
       F->addFnAttr(Attribute::WriteOnly);