[llvm-commits] [llvm] r100459 - /llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

[Dan Gohman]

Author: djg
Date: Mon Apr  5 15:24:08 2010
New Revision: 100459

URL: http://llvm.org/viewvc/llvm-project?rev=100459&view=rev
Log:
Add a comment.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=100459&r1=100458&r2=100459&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Apr  5 15:24:08 2010
@@ -3518,6 +3518,12 @@
                                    true, DstSV, DstSVOff, SrcSV, SrcSVOff);
   }
 
+  // FIXME: If the memcpy is volatile (isVol), lowering it to a plain libc
+  // memcpy is not guaranteed to be safe. libc memcpys aren't required to
+  // respect volatile, so they may do things like read or write memory
+  // beyond the given memory regions. But fixing this isn't easy, and most
+  // people don't care.
+
   // Emit a library call.
   TargetLowering::ArgListTy Args;
   TargetLowering::ArgListEntry Entry;