[llvm-commits] [llvm] r62713 - /llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
gohman at apple.com
Wed Jan 21 12:50:09 PST 2009
Date: Wed Jan 21 14:50:09 2009
New Revision: 62713
Add a comment to SelectionDAG::ReplaceAllUsesWith to describe a subtle
iteraction with SelectionDAG CSE.
--- llvm/trunk/include/llvm/CodeGen/SelectionDAG.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAG.h Wed Jan 21 14:50:09 2009
@@ -680,6 +680,11 @@
/// informed about nodes that are deleted and modified due to recursive
/// changes in the dag.
+ /// These functions only replace all existing uses. It's possible that as
+ /// these replacements are being performed, CSE may cause the From node
+ /// to be given new uses. These new uses of From are left in place, and
+ /// not automatically transfered to To.
void ReplaceAllUsesWith(SDValue From, SDValue Op,
DAGUpdateListener *UpdateListener = 0);
void ReplaceAllUsesWith(SDNode *From, SDNode *To,
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