Remove dependency between InaccessibleMem and TargetMem

Also adds a not in LangRef saying that target memories are in
development stage

Author: CarolineConcatto

llvm/docs/LangRef.rst

@@ -2223,7 +2223,8 @@ For example:
     - ``errnomem``: This refers to accesses to the ``errno`` variable.
     - ``target_mem#`` : These refer to target specific state that cannot be
       accessed by any other means. # is a number between 0 and 1 inclusive.
-
+      Note: The target_mem locations are experimental and intended for internal
+      testing only. They must not be used in production code.
 
     - The default access kind (specified without a location prefix) applies to
       all locations that haven't been specified explicitly, including those that

llvm/include/llvm/Support/ModRef.h

@@ -238,8 +238,6 @@ template <typename LocationEnum> class MemoryEffectsBase {
   /// Whether this function only (at most) accesses inaccessible memory.
   bool onlyAccessesInaccessibleMem() const {
     return getWithoutLoc(Location::InaccessibleMem)
-        .getWithoutLoc(IRMemLocation::TargetMem0)
-        .getWithoutLoc(IRMemLocation::TargetMem1)
         .doesNotAccessMemory();
   }
 
@@ -253,8 +251,6 @@ template <typename LocationEnum> class MemoryEffectsBase {
   bool onlyAccessesInaccessibleOrArgMem() const {
     return getWithoutLoc(Location::InaccessibleMem)
         .getWithoutLoc(Location::ArgMem)
-        .getWithoutLoc(Location::TargetMem0)
-        .getWithoutLoc(Location::TargetMem1)
         .doesNotAccessMemory();
   }