From: Nick Lewycky <nicholas@mxc.ca>
Date: Wed, 26 Jan 2011 08:40:22 +0000 (+0000)
Subject: Fix memory corruption. If one of the SCEV creation functions calls another but
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e19b7b80bd1bf48f9a6f036cf1cbc5f65445090a;p=oota-llvm.git

Fix memory corruption. If one of the SCEV creation functions calls another but
doesn't return immediately after then the insert position in UniqueSCEVs will
be out of date. No test because this is a memory corruption issue. Fixes PR9051!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124282 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index c10af50dd59..c2f3ac071de 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -831,6 +831,7 @@ const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op,
     }
     if (!hasTrunc)
       return getAddExpr(Operands, false, false);
+    UniqueSCEVs.FindNodeOrInsertPos(ID, IP);  // Mutates IP, returns NULL.
   }
 
   // trunc(x1*x2*...*xN) --> trunc(x1)*trunc(x2)*...*trunc(xN) if we can
@@ -845,6 +846,7 @@ const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op,
     }
     if (!hasTrunc)
       return getMulExpr(Operands, false, false);
+    UniqueSCEVs.FindNodeOrInsertPos(ID, IP);  // Mutates IP, returns NULL.
   }
 
   // If the input value is a chrec scev, truncate the chrec's operands.