Add InaccessibleMemOnly and inaccessibleMemOrArgMemOnly attributes

Summary:
This patch introduces two new function attributes 

InaccessibleMemOnly: This attribute indicates that the function may only access memory that is not accessible by the program/IR being compiled. This is a weaker form of ReadNone.
inaccessibleMemOrArgMemOnly: This attribute indicates that the function may only access memory that is either not accessible by the program/IR being compiled, or is pointed to by its pointer arguments. This is a weaker form of  ArgMemOnly

Test cases have been updated. This revision uses this (https://github.com/llvm-mirror/llvm/commit/d001932f3a8aa1ebd1555162fdce365f011bc292) as reference.

Reviewers: jmolloy, hfinkel

Subscribers: reames, joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D15499

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255778 91177308-0d34-0410-b5e6-96231b3b80d8

test/Bitcode/attributes.ll

@@ -204,7 +204,7 @@ define void @f34()
 ; CHECK: define void @f34()
 {
         call void @nobuiltin() nobuiltin
-; CHECK: call void @nobuiltin() #28
+; CHECK: call void @nobuiltin() #30
         ret void;
 }
 
@@ -277,6 +277,16 @@ define void @f47() norecurse {
   ret void
 }
 
+; CHECK: define void @f48() #28
+define void @f48() inaccessiblememonly {
+  ret void
+}
+
+; CHECK: define void @f49() #29
+define void @f49() inaccessiblemem_or_argmemonly {
+  ret void
+}
+
 ; CHECK: attributes #0 = { noreturn }
 ; CHECK: attributes #1 = { nounwind }
 ; CHECK: attributes #2 = { readnone }
@@ -305,4 +315,6 @@ define void @f47() norecurse {
 ; CHECK: attributes #25 = { convergent }
 ; CHECK: attributes #26 = { argmemonly }
 ; CHECK: attributes #27 = { norecurse }
-; CHECK: attributes #28 = { nobuiltin }
+; CHECK: attributes #28 = { inaccessiblememonly }
+; CHECK: attributes #29 = { inaccessiblemem_or_argmemonly }
+; CHECK: attributes #30 = { nobuiltin }