[llvm-commits] [llvm] r74338 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Dan Gohman]

Author: djg
Date: Fri Jun 26 17:17:21 2009
New Revision: 74338

URL: http://llvm.org/viewvc/llvm-project?rev=74338&view=rev
Log:
Fix SCEVAddRecExpr::isLoopInvariant to test if all of its operands
are loop invariant, not just the start operand.

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=74338&r1=74337&r2=74338&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Fri Jun 26 17:17:21 2009
@@ -327,12 +327,22 @@
 
 
 bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
-  // This recurrence is invariant w.r.t to QueryLoop iff QueryLoop doesn't
-  // contain L and if the start is invariant.
   // Add recurrences are never invariant in the function-body (null loop).
-  return QueryLoop &&
-         !QueryLoop->contains(L->getHeader()) &&
-         getOperand(0)->isLoopInvariant(QueryLoop);
+  if (!QueryLoop)
+    return false;
+
+  // This recurrence is variant w.r.t. QueryLoop if QueryLoop contains L.
+  if (QueryLoop->contains(L->getHeader()))
+    return false;
+
+  // This recurrence is variant w.r.t. QueryLoop if any of its operands
+  // are variant.
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+    if (!getOperand(i)->isLoopInvariant(QueryLoop))
+      return false;
+
+  // Otherwise it's loop-invariant.
+  return true;
 }