[llvm-commits] [llvm] r111034 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Dan Gohman]

Author: djg
Date: Fri Aug 13 15:11:39 2010
New Revision: 111034

URL: http://llvm.org/viewvc/llvm-project?rev=111034&view=rev
Log:
An add recurrence is loop-invariant in any loop inside of its
associated loop. This avoids potentially expensive traversals
of the add recurrence's operands.

Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=111034&r1=111033&r2=111034&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Fri Aug 13 15:11:39 2010
@@ -303,6 +303,10 @@
   if (QueryLoop->contains(L))
     return false;
 
+  // This recurrence is invariant w.r.t. QueryLoop if L contains QueryLoop.
+  if (L->contains(QueryLoop))
+    return true;
+
   // This recurrence is variant w.r.t. QueryLoop if any of its operands
   // are variant.
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)