[AA] Export the isBaseOfObject() API (NFC)

This is also useful outside BasicAA.

Author: nikic

llvm/include/llvm/Analysis/AliasAnalysis.h

@@ -875,6 +875,13 @@ bool isIdentifiedObject(const Value *V);
 /// IdentifiedObjects.
 bool isIdentifiedFunctionLocal(const Value *V);
 
+/// Return true if we know V to the base address of the corresponding memory
+/// object.  This implies that any address less than V must be out of bounds
+/// for the underlying object.  Note that just being isIdentifiedObject() is
+/// not enough - For example, a negative offset from a noalias argument or call
+/// can be inbounds w.r.t the actual underlying object.
+bool isBaseOfObject(const Value *V);
+
 /// Returns true if the pointer is one which would have been considered an
 /// escape by isNonEscapingLocalObject.
 bool isEscapeSource(const Value *V);

llvm/lib/Analysis/AliasAnalysis.cpp

@@ -828,6 +828,14 @@ bool llvm::isIdentifiedFunctionLocal(const Value *V) {
   return isa<AllocaInst>(V) || isNoAliasCall(V) || isNoAliasOrByValArgument(V);
 }
 
+bool llvm::isBaseOfObject(const Value *V) {
+  // TODO: We can handle other cases here
+  // 1) For GC languages, arguments to functions are often required to be
+  //    base pointers.
+  // 2) Result of allocation routines are often base pointers.  Leverage TLI.
+  return (isa<AllocaInst>(V) || isa<GlobalVariable>(V));
+}
+
 bool llvm::isEscapeSource(const Value *V) {
   if (auto *CB = dyn_cast<CallBase>(V))
     return !isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(CB,

llvm/lib/Analysis/BasicAliasAnalysis.cpp

@@ -1074,19 +1074,6 @@ ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call1,
   return ModRefInfo::ModRef;
 }
 
-/// Return true if we know V to the base address of the corresponding memory
-/// object.  This implies that any address less than V must be out of bounds
-/// for the underlying object.  Note that just being isIdentifiedObject() is
-/// not enough - For example, a negative offset from a noalias argument or call
-/// can be inbounds w.r.t the actual underlying object.
-static bool isBaseOfObject(const Value *V) {
-  // TODO: We can handle other cases here
-  // 1) For GC languages, arguments to functions are often required to be
-  //    base pointers.
-  // 2) Result of allocation routines are often base pointers.  Leverage TLI.
-  return (isa<AllocaInst>(V) || isa<GlobalVariable>(V));
-}
-
 /// Provides a bunch of ad-hoc rules to disambiguate a GEP instruction against
 /// another pointer.
 ///