I've changed the semantics of MERGE_VALUES a bit. It's now allowed to live until scheduling. It's deleted when the scheduler translate DAG nodes to machine instructions.

This is currently used by X86 to handle atomic_load_add when the output of the node is not used. I believe there is a better solution. But I find MERGE_VALUES useful for selecting multi-output node when the dead output can be selected as a IMPLICIT_DEF.

llvm-svn: 77583

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/include/llvm/CodeGen/SelectionDAGNodes.h b/llvm/include/llvm/CodeGen/SelectionDAGNodes.h
index 62c3769ebe6..6dc55fff841 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -225,9 +225,9 @@ namespace ISD {
 
     // MERGE_VALUES - This node takes multiple discrete operands and returns
     // them all as its individual results.  This nodes has exactly the same
-    // number of inputs and outputs, and is only valid before legalization.
-    // This node is useful for some pieces of the code generator that want to
-    // think about a single node with multiple results, not multiple nodes.
+    // number of inputs and outputs. This node is useful for some pieces of the
+    // code generator that want to think about a single node with multiple
+    // results, not multiple nodes.
     MERGE_VALUES,
 
     // Simple integer binary arithmetic operators.