[AA] Export isEscapeSource() API (NFC)

Export API that was previously private to BasicAliasAnalysis and
will be used in D127202.

1 files changed, 22 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 7a8cccc..e249c38 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -987,6 +987,28 @@ bool llvm::isIdentifiedFunctionLocal(const Value *V) {
   return isa<AllocaInst>(V) || isNoAliasCall(V) || isNoAliasOrByValArgument(V);
 }
 
+bool llvm::isEscapeSource(const Value *V) {
+  if (auto *CB = dyn_cast<CallBase>(V))
+    return !isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(CB,
+                                                                        true);
+
+  // The load case works because isNonEscapingLocalObject considers all
+  // stores to be escapes (it passes true for the StoreCaptures argument
+  // to PointerMayBeCaptured).
+  if (isa<LoadInst>(V))
+    return true;
+
+  // The inttoptr case works because isNonEscapingLocalObject considers all
+  // means of converting or equating a pointer to an int (ptrtoint, ptr store
+  // which could be followed by an integer load, ptr<->int compare) as
+  // escaping, and objects located at well-known addresses via platform-specific
+  // means cannot be considered non-escaping local objects.
+  if (isa<IntToPtrInst>(V))
+    return true;
+
+  return false;
+}
+
 bool llvm::isNotVisibleOnUnwind(const Value *Object,
                                 bool &RequiresNoCaptureBeforeUnwind) {
   RequiresNoCaptureBeforeUnwind = false;