Remove dead var

[oota-llvm.git] / lib / Analysis / AliasSetTracker.cpp

diff --git a/lib/Analysis/AliasSetTracker.cpp b/lib/Analysis/AliasSetTracker.cpp
index 22396b5d8724f5cf2a417ceac4bc6ab8670a1e05..2da144c35fe809b52b91a31cc5178e4f2fc75849 100644 (file)
--- a/lib/Analysis/AliasSetTracker.cpp
+++ b/lib/Analysis/AliasSetTracker.cpp
@@ -13,9 +13,7 @@
 
 #include "llvm/Analysis/AliasSetTracker.h"
 #include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/iMemory.h"
-#include "llvm/iOther.h"
-#include "llvm/iTerminators.h"
+#include "llvm/Instructions.h"
 #include "llvm/Pass.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Assembly/Writer.h"
@@ -41,9 +39,6 @@ void AliasSet::mergeSetIn(AliasSet &AS) {
     AS.CallSites.clear();
   }
   
-  // FIXME: If AS's refcount is zero, nuke it now...
-  assert(RefCount != 0);
-
   AS.Forward = this;  // Forward across AS now...
   addRef();           // AS is now pointing to us...
 
@@ -55,6 +50,7 @@ void AliasSet::mergeSetIn(AliasSet &AS) {
 
     AS.PtrList = 0;
     AS.PtrListEnd = &AS.PtrList;
+    assert(*AS.PtrListEnd == 0 && "End of list is not null?");
   }
 }
 
@@ -72,13 +68,13 @@ void AliasSet::removeFromTracker(AliasSetTracker &AST) {
 }
 
 void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
-                          unsigned Size) {
+                          unsigned Size, bool KnownMustAlias) {
   assert(!Entry.second.hasAliasSet() && "Entry already in set!");
 
-  AliasAnalysis &AA = AST.getAliasAnalysis();
-
-  if (isMustAlias())    // Check to see if we have to downgrade to _may_ alias
+  // Check to see if we have to downgrade to _may_ alias.
+  if (isMustAlias() && !KnownMustAlias)
     if (HashNodePair *P = getSomePointer()) {
+      AliasAnalysis &AA = AST.getAliasAnalysis();
       AliasAnalysis::AliasResult Result =
         AA.alias(P->first, P->second.getSize(), Entry.first, Size);
       if (Result == AliasAnalysis::MayAlias)
@@ -95,6 +91,7 @@ void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
   assert(*PtrListEnd == 0 && "End of list is not null?");
   *PtrListEnd = &Entry;
   PtrListEnd = Entry.second.setPrevInList(PtrListEnd);
+  assert(*PtrListEnd == 0 && "End of list is not null?");
   addRef();               // Entry points to alias set...
 }
 
@@ -138,20 +135,38 @@ bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
       return true;
 
   // Check the call sites list and invoke list...
-  if (!CallSites.empty())
-    // FIXME: this is pessimistic!
-    return true;
+  if (!CallSites.empty()) {
+    if (AA.hasNoModRefInfoForCalls())
+      return true;
+
+    for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
+      if (AA.getModRefInfo(CallSites[i], const_cast<Value*>(Ptr), Size)
+                   != AliasAnalysis::NoModRef)
+        return true;
+  }
 
   return false;
 }
 
 bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
-  // FIXME: Use mod/ref information to prune this better!
   if (Function *F = CS.getCalledFunction())
     if (AA.doesNotAccessMemory(F))
       return false;
 
-  return true;
+  if (AA.hasNoModRefInfoForCalls())
+    return true;
+
+  for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
+    if (AA.getModRefInfo(CallSites[i], CS) != AliasAnalysis::NoModRef ||
+        AA.getModRefInfo(CS, CallSites[i]) != AliasAnalysis::NoModRef)
+      return true;
+
+  for (iterator I = begin(), E = end(); I != E; ++I)
+    if (AA.getModRefInfo(CS, I.getPointer(), I.getSize()) !=
+           AliasAnalysis::NoModRef)
+      return true;
+
+  return false;
 }
 
 
@@ -198,7 +213,8 @@ AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size,
   AliasSet::HashNodePair &Entry = getEntryFor(Pointer);
 
   // Check to see if the pointer is already known...
-  if (Entry.second.hasAliasSet() && Size <= Entry.second.getSize()) {
+  if (Entry.second.hasAliasSet()) {
+    Entry.second.updateSize(Size);
     // Return the set!
     return *Entry.second.getAliasSet(*this)->getForwardedTarget(*this);
   } else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
@@ -214,6 +230,13 @@ AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, unsigned Size,
   }
 }
 
+bool AliasSetTracker::add(Value *Ptr, unsigned Size) {
+  bool NewPtr;
+  addPointer(Ptr, Size, AliasSet::NoModRef, NewPtr);
+  return NewPtr;
+}
+
+
 bool AliasSetTracker::add(LoadInst *LI) {
   bool NewPtr;
   AliasSet &AS = addPointer(LI->getOperand(0),
@@ -242,7 +265,6 @@ bool AliasSetTracker::add(FreeInst *FI) {
 
 
 bool AliasSetTracker::add(CallSite CS) {
-  bool NewPtr;
   if (Function *F = CS.getCalledFunction())
     if (AA.doesNotAccessMemory(F))
       return true; // doesn't alias anything
@@ -318,6 +340,12 @@ void AliasSetTracker::remove(AliasSet &AS) {
   } while (!SetDead);
 }
 
+bool AliasSetTracker::remove(Value *Ptr, unsigned Size) {
+  AliasSet *AS = findAliasSetForPointer(Ptr, Size);
+  if (!AS) return false;
+  remove(*AS);
+  return true;
+}
 
 bool AliasSetTracker::remove(LoadInst *LI) {
   unsigned Size = AA.getTargetData().getTypeSize(LI->getType());
@@ -373,7 +401,10 @@ bool AliasSetTracker::remove(Instruction *I) {
 // dangling pointers to deleted instructions.
 //
 void AliasSetTracker::deleteValue(Value *PtrVal) {
-  // First, look up the PointerRec for this pointer...
+  // Notify the alias analysis implementation that this value is gone.
+  AA.deleteValue(PtrVal);
+
+  // First, look up the PointerRec for this pointer.
   hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal);
   if (I == PointerMap.end()) return;  // Noop
 
@@ -388,6 +419,29 @@ void AliasSetTracker::deleteValue(Value *PtrVal) {
   PointerMap.erase(I);
 }
 
+// copyValue - This method should be used whenever a preexisting value in the
+// program is copied or cloned, introducing a new value.  Note that it is ok for
+// clients that use this method to introduce the same value multiple times: if
+// the tracker already knows about a value, it will ignore the request.
+//
+void AliasSetTracker::copyValue(Value *From, Value *To) {
+  // Notify the alias analysis implementation that this value is copied.
+  AA.copyValue(From, To);
+
+  // First, look up the PointerRec for this pointer.
+  hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(From);
+  if (I == PointerMap.end() || !I->second.hasAliasSet())
+    return;  // Noop
+
+  AliasSet::HashNodePair &Entry = getEntryFor(To);
+  if (Entry.second.hasAliasSet()) return;    // Already in the tracker!
+
+  // Add it to the alias set it aliases...
+  AliasSet *AS = I->second.getAliasSet(*this);
+  AS->addPointer(*this, Entry, I->second.getSize(), true);
+}
+
+
 
 //===----------------------------------------------------------------------===//
 //               AliasSet/AliasSetTracker Printing Support