4 files changed, 40 insertions, 5 deletions
diff --git a/lib/Analysis/IPA/Andersens.cpp b/lib/Analysis/IPA/Andersens.cpp
index b5129a7d3b..e37a9dbb7a 100644
--- a/lib/Analysis/IPA/Andersens.cpp
+++ b/lib/Analysis/IPA/Andersens.cpp
@@ -1017,6 +1017,8 @@ bool Andersens::AnalyzeUsesOfFunction(Value *V) {
       }
     } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) {
       if (AnalyzeUsesOfFunction(GEP)) return true;
+    } else if (isa<FreeInst>(*UI) || isFreeCall(*UI)) {
+      return false;
     } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
       // Make sure that this is just the function being called, not that it is
       // passing into the function.
@@ -1038,8 +1040,6 @@ bool Andersens::AnalyzeUsesOfFunction(Value *V) {
     } else if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) {
       if (!isa<ConstantPointerNull>(ICI->getOperand(1)))
         return true;  // Allow comparison against null.
-    } else if (isa<FreeInst>(*UI)) {
-      return false;
     } else {
       return true;
     }
diff --git a/lib/Analysis/IPA/GlobalsModRef.cpp b/lib/Analysis/IPA/GlobalsModRef.cpp
index 7949288340..d83ea48080 100644
--- a/lib/Analysis/IPA/GlobalsModRef.cpp
+++ b/lib/Analysis/IPA/GlobalsModRef.cpp
@@ -240,6 +240,8 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
     } else if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI)) {
       if (AnalyzeUsesOfPointer(BCI, Readers, Writers, OkayStoreDest))
         return true;
+    } else if (isa<FreeInst>(*UI) || isFreeCall(*UI)) {
+      Writers.push_back(cast<Instruction>(*UI)->getParent()->getParent());
     } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
       // Make sure that this is just the function being called, not that it is
       // passing into the function.
@@ -261,8 +263,6 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
     } else if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) {
       if (!isa<ConstantPointerNull>(ICI->getOperand(1)))
         return true;  // Allow comparison against null.
-    } else if (FreeInst *F = dyn_cast<FreeInst>(*UI)) {
-      Writers.push_back(F->getParent()->getParent());
     } else {
       return true;
     }
@@ -439,7 +439,8 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
           if (cast<StoreInst>(*II).isVolatile())
             // Treat volatile stores as reading memory somewhere.
             FunctionEffect |= Ref;
-        } else if (isMalloc(&cast<Instruction>(*II)) || isa<FreeInst>(*II)) {
+        } else if (isMalloc(&cast<Instruction>(*II)) || isa<FreeInst>(*II) ||
+                   isFreeCall(&cast<Instruction>(*II))) {
           FunctionEffect |= ModRef;
         }
 
diff --git a/lib/Analysis/MallocHelper.cpp b/lib/Analysis/MallocHelper.cpp
index e7bb41eeec..511de9d6a5 100644
--- a/lib/Analysis/MallocHelper.cpp
+++ b/lib/Analysis/MallocHelper.cpp
@@ -263,3 +263,29 @@ Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
   assert(BO && "getMallocArraySize not constant but not multiplication either");
   return BO->getOperand(0);
 }
+
+/// isFreeCall - Returns true if the the value is a call to the builtin free()
+bool llvm::isFreeCall(const Value* I) {
+  const CallInst *CI = dyn_cast<CallInst>(I);
+  if (!CI)
+    return false;
+
+  const Module* M = CI->getParent()->getParent()->getParent();
+  Function *FreeFunc = M->getFunction("free");
+
+  if (CI->getOperand(0) != FreeFunc)
+    return false;
+
+  // Check free prototype.
+  // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin 
+  // attribute will exist.
+  const FunctionType *FTy = FreeFunc->getFunctionType();
+  if (FTy->getReturnType() != Type::getVoidTy(M->getContext()))
+    return false;
+  if (FTy->getNumParams() != 1)
+    return false;
+  if (FTy->param_begin()->get() != Type::getInt8PtrTy(M->getContext()))
+    return false;
+
+  return true;
+}
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index c3aa5bc930..ce7674003f 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -118,6 +118,10 @@ getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall,
       
       // FreeInsts erase the entire structure
       PointerSize = ~0ULL;
+    } else if (isFreeCall(Inst)) {
+      Pointer = Inst->getOperand(0);
+      // calls to free() erase the entire structure
+      PointerSize = ~0ULL;
     } else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
       // Debug intrinsics don't cause dependences.
       if (isa<DbgInfoIntrinsic>(Inst)) continue;
@@ -314,6 +318,10 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
       MemPtr = LI->getPointerOperand();
       MemSize = AA->getTypeStoreSize(LI->getType());
     }
+  } else if (isFreeCall(QueryInst)) {
+    MemPtr = QueryInst->getOperand(0);
+    // calls to free() erase the entire structure, not just a field.
+    MemSize = ~0UL;
   } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
     CallSite QueryCS = CallSite::get(QueryInst);
     bool isReadOnly = AA->onlyReadsMemory(QueryCS);