[AA] Merge isNonEscapingLocalObject() into SimpleCaptureAnalysis (NFC)

isNonEscapingLocalObject() is only used by SimpleCaptureAnalysis
and tightly integrated with its implementation (in particular its
cache), so inline and simplify the implementation.

Author: nikic

llvm/include/llvm/Analysis/CaptureTracking.h

@@ -195,12 +195,6 @@ namespace llvm {
   /// implicit captures such as for external globals.
   LLVM_ABI void PointerMayBeCaptured(const Value *V, CaptureTracker *Tracker,
                                      unsigned MaxUsesToExplore = 0);
-
-  /// Returns true if the pointer is to a function-local object that never
-  /// escapes from the function.
-  LLVM_ABI bool isNonEscapingLocalObject(
-      const Value *V,
-      SmallDenseMap<const Value *, bool, 8> *IsCapturedCache = nullptr);
 } // end namespace llvm
 
 #endif

llvm/lib/Analysis/BasicAliasAnalysis.cpp

@@ -199,7 +199,17 @@ CaptureAnalysis::~CaptureAnalysis() = default;
 bool SimpleCaptureAnalysis::isNotCapturedBefore(const Value *Object,
                                                 const Instruction *I,
                                                 bool OrAt) {
-  return isNonEscapingLocalObject(Object, &IsCapturedCache);
+  if (!isIdentifiedFunctionLocal(Object))
+    return false;
+
+  auto [CacheIt, Inserted] = IsCapturedCache.insert({Object, false});
+  if (!Inserted)
+    return CacheIt->second;
+
+  bool Ret = !capturesAnything(PointerMayBeCaptured(
+      Object, /*ReturnCaptures=*/false, CaptureComponents::Provenance));
+  CacheIt->second = Ret;
+  return Ret;
 }
 
 static bool isNotInCycle(const Instruction *I, const DominatorTree *DT,

llvm/lib/Analysis/CaptureTracking.cpp

@@ -447,27 +447,3 @@ void llvm::PointerMayBeCaptured(const Value *V, CaptureTracker *Tracker,
 
   // All uses examined.
 }
-
-bool llvm::isNonEscapingLocalObject(
-    const Value *V, SmallDenseMap<const Value *, bool, 8> *IsCapturedCache) {
-  SmallDenseMap<const Value *, bool, 8>::iterator CacheIt;
-  if (IsCapturedCache) {
-    bool Inserted;
-    std::tie(CacheIt, Inserted) = IsCapturedCache->insert({V, false});
-    if (!Inserted)
-      // Found cached result, return it!
-      return CacheIt->second;
-  }
-
-  // If this is an identified function-local object, check to see if it escapes.
-  // We only care about provenance here, not address capture.
-  if (isIdentifiedFunctionLocal(V)) {
-    bool Ret = !capturesAnything(PointerMayBeCaptured(
-        V, /*ReturnCaptures=*/false, CaptureComponents::Provenance));
-    if (IsCapturedCache)
-      CacheIt->second = Ret;
-    return Ret;
-  }
-
-  return false;
-}