[llvm] r174100 - Document another instsimplify assumption.

[Dan Gohman]

Author: djg
Date: Thu Jan 31 16:13:00 2013
New Revision: 174100

URL: http://llvm.org/viewvc/llvm-project?rev=174100&view=rev
Log:
Document another instsimplify assumption.

Modified:
    llvm/trunk/include/llvm/Analysis/InstructionSimplify.h

Modified: llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/InstructionSimplify.h?rev=174100&r1=174099&r2=174100&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/InstructionSimplify.h (original)
+++ llvm/trunk/include/llvm/Analysis/InstructionSimplify.h Thu Jan 31 16:13:00 2013
@@ -20,6 +20,13 @@
 // values. This will prevent other code from seeing the same undef uses and
 // resolving them to different values.
 //
+// These routines are designed to tolerate moderately incomplete IR, such as
+// instructions that are not connected to basic blocks yet. However, they do
+// require that all the IR that they encounter be valid. In particular, they
+// require that all non-constant values be defined in the same function, and the
+// same call context of that function (and not split between caller and callee
+// contexts of a directly recursive call, for example).
+//
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H