2 files changed, 10 insertions, 6 deletions
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 005c824024f..817589064a3 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -470,10 +470,13 @@ CodeGenFunction::emitBuiltinObjectSize(const Expr *E, unsigned Type,
   assert(Ptr->getType()->isPointerTy() &&
          "Non-pointer passed to __builtin_object_size?");
 
-  // LLVM only supports 0 and 2, make sure that we pass along that as a boolean.
-  auto *CI = ConstantInt::get(Builder.getInt1Ty(), (Type & 2) >> 1);
   Value *F = CGM.getIntrinsic(Intrinsic::objectsize, {ResType, Ptr->getType()});
-  return Builder.CreateCall(F, {Ptr, CI});
+
+  // LLVM only supports 0 and 2, make sure that we pass along that as a boolean.
+  Value *Min = Builder.getInt1((Type & 2) != 0);
+  // For GCC compatability, __builtin_object_size treat NULL as unknown size.
+  Value *NullIsUnknown = Builder.getTrue();
+  return Builder.CreateCall(F, {Ptr, Min, NullIsUnknown});
 }
 
 // Many of MSVC builtins are on both x64 and ARM; to avoid repeating code, we
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 1118bfadc94..1a95eb10451 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -581,10 +581,11 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
     llvm::Type *Tys[2] = { IntPtrTy, Int8PtrTy };
     llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys);
     llvm::Value *Min = Builder.getFalse();
+    llvm::Value *NullIsUnknown = Builder.getFalse();
     llvm::Value *CastAddr = Builder.CreateBitCast(Ptr, Int8PtrTy);
-    llvm::Value *LargeEnough =
-        Builder.CreateICmpUGE(Builder.CreateCall(F, {CastAddr, Min}),
-                              llvm::ConstantInt::get(IntPtrTy, Size));
+    llvm::Value *LargeEnough = Builder.CreateICmpUGE(
+        Builder.CreateCall(F, {CastAddr, Min, NullIsUnknown}),
+        llvm::ConstantInt::get(IntPtrTy, Size));
     Checks.push_back(std::make_pair(LargeEnough, SanitizerKind::ObjectSize));
   }