commit 8a18d6b48f9877dbb7fbb88cb294201b20b9fb05
author Dan Gohman <gohman@apple.com> Wed Jun 30 06:58:35 2010 +0000
committer Dan Gohman <gohman@apple.com> Wed Jun 30 06:58:35 2010 +0000
tree ad5f02d1fd5d69b7d0bc3ff781d8227ae108e576
parent 49bda917dbfbb09e2410272ebb1c6e4a2a3f45a2

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

lib/Analysis/ScalarEvolution.cpp

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index b5acd6b..240126e 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -2958,7 +2958,8 @@
       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()) {