[llvm-commits] [llvm] r63851 - /llvm/trunk/include/llvm/Target/TargetInstrDesc.h

Evan Cheng evan.cheng at apple.com
Thu Feb 5 00:41:57 PST 2009


Author: evancheng
Date: Thu Feb  5 02:41:53 2009
New Revision: 63851

URL: http://llvm.org/viewvc/llvm-project?rev=63851&view=rev
Log:
Clarify comments.

Modified:
    llvm/trunk/include/llvm/Target/TargetInstrDesc.h

Modified: llvm/trunk/include/llvm/Target/TargetInstrDesc.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetInstrDesc.h?rev=63851&r1=63850&r2=63851&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Target/TargetInstrDesc.h (original)
+++ llvm/trunk/include/llvm/Target/TargetInstrDesc.h Thu Feb  5 02:41:53 2009
@@ -407,9 +407,10 @@
 
   /// isAsCheapAsAMove - Returns true if this instruction has the same cost (or
   /// less) than a move instruction. This is useful during certain types of
-  /// rematerializations (e.g., during two-address conversion) where we would
-  /// like to remat the instruction, but not if it costs more than moving the
-  /// instruction into the appropriate register.
+  /// optimizations (e.g., remat during two-address conversion or machine licm)
+  /// where we would like to remat or hoist the instruction, but not if it costs
+  /// more than moving the instruction into the appropriate register. Note, we
+  /// are not marking copies from and to the same register class with this flag.
   bool isAsCheapAsAMove() const {
     return Flags & (1 << TID::CheapAsAMove);
   }





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