If the first argument of __builtin_object_size can be folded to a constant

pointer, but such folding encounters side-effects, ignore the side-effects
rather than performing them at runtime: CodeGen generates wrong code for
__builtin_object_size in that case.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@157310 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 944fbe9f19..a3d4af72da 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -335,6 +335,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
     return RValue::get(Builder.CreateCall(F, ArgValue));
   }
   case Builtin::BI__builtin_object_size: {
+    // We rely on constant folding to deal with expressions with side effects.
+    assert(!E->getArg(0)->HasSideEffects(getContext()) &&
+           "should have been constant folded");
+
     // We pass this builtin onto the optimizer so that it can
     // figure out the object size in more complex cases.
     llvm::Type *ResType = ConvertType(E->getType());