From: Dan Gohman <gohman@apple.com>
Date: Wed, 30 Jun 2010 06:58:35 +0000 (+0000)
Subject: When computing a new ConservativeResult, intersect it with
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=8a18d6b48f9877dbb7fbb88cb294201b20b9fb05;p=oota-llvm.git

When computing a new ConservativeResult, intersect it with
the old one instead of replacing it, to be more precise.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107256 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index b5acd6bfd6e..240126eef8c 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -2958,7 +2958,8 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) {
       if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
         if (!C->getValue()->isZero())
           ConservativeResult =
-            ConstantRange(C->getValue()->getValue(), APInt(BitWidth, 0));
+            ConservativeResult.intersectWith(
+              ConstantRange(C->getValue()->getValue(), APInt(BitWidth, 0)));
 
     // TODO: non-affine addrec
     if (AddRec->isAffine()) {