[llvm-commits] [llvm] r63239 - /llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h

[Dan Gohman]

Author: djg
Date: Wed Jan 28 15:34:36 2009
New Revision: 63239

URL: http://llvm.org/viewvc/llvm-project?rev=63239&view=rev
Log:
Add more comments describing SDNode operator codes.

Modified:
    llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h

Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h?rev=63239&r1=63238&r2=63239&view=diff

==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h Wed Jan 28 15:34:36 2009
@@ -60,15 +60,19 @@
 namespace ISD {
 
   //===--------------------------------------------------------------------===//
-  /// ISD::NodeType enum - This enum defines all of the operators valid in a
-  /// SelectionDAG.
+  /// ISD::NodeType enum - This enum defines the target-independent operators
+  /// for a SelectionDAG.
   ///
-  /// These are sometimes called the target-independent operators; targets
-  /// may also define target-dependent operators. For example, on x86, these
-  /// are the enum values in the X86ISD namespace. Targets should aim to use
-  /// target-independent operators to model their instruction sets as much
-  /// as possible, and only use target-dependent operators when they have
-  /// special requirements.
+  /// Targets may also define target-dependent operator codes for SDNodes. For
+  /// example, on x86, these are the enum values in the X86ISD namespace.
+  /// Targets should aim to use target-independent operators to model their
+  /// instruction sets as much as possible, and only use target-dependent
+  /// operators when they have special requirements.
+  ///
+  /// Finally, during and after selection proper, SNodes may use special
+  /// operator codes that correspond directly with MachineInstr opcodes. These
+  /// are used to represent selected instructions. See the isMachineOpcode()
+  /// and getMachineOpcode() member functions of SDNode.
   ///
   enum NodeType {
     // DELETED_NODE - This is an illegal flag value that is used to catch