[llvm-commits] [llvm] r46218 - /llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp

[Owen Anderson]

Author: resistor
Date: Mon Jan 21 16:03:00 2008
New Revision: 46218

URL: http://llvm.org/viewvc/llvm-project?rev=46218&view=rev
Log:
Clarify a deviation from the original algorithm.

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

Modified: llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp?rev=46218&r1=46217&r2=46218&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp (original)
+++ llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp Mon Jan 21 16:03:00 2008
@@ -552,7 +552,10 @@
       DomForestNode* child = *CI;   
       
       // If the current node is live-out of the defining block of one of its
-      // children, insert a copy for it
+      // children, insert a copy for it.  NOTE: The paper actually calls for
+      // a more elaborate heuristic for determining whether to insert copies
+      // for the child or the parent.  In the interest of simplicity, we're
+      // just always choosing the parent.
       if (isLiveOut(DFNode->getReg(),
           MRI.getVRegDef(child->getReg())->getParent(), MRI, LV)) {
         // Insert copies for parent