From: Dan Gohman <gohman@apple.com>
Date: Fri, 26 Jun 2009 22:17:21 +0000 (+0000)
Subject: Fix SCEVAddRecExpr::isLoopInvariant to test if all of its operands
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=e890eead222abf84fc171b28891a68b65e9addf5;p=oota-llvm.git

Fix SCEVAddRecExpr::isLoopInvariant to test if all of its operands
are loop invariant, not just the start operand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74338 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index c98414d66a4..2d8bd7d53a6 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -327,12 +327,22 @@ SCEVAddRecExpr::replaceSymbolicValuesWithConcrete(const SCEV *Sym,
 
 
 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;
 }