From 97f870366b7bef70e3d24a1a034032e6c4a9d79f Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Tue, 4 Jun 2013 19:58:28 +0000
Subject: [PATCH] Merging r183060:
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 r183060 | atrick | 2013-05-31 16:34:46 -0700 (Fri, 31 May 2013) | 11 lines

Prevent loop-unroll from making assumptions about undefined behavior.

Fixes rdar:14036816, PR16130.

There is an opportunity to compute precise trip counts for 'or'
expressions and multi-exit loops.
rdar:14038809: Optimize trip count computation for multi-exit loops.

To do this we need to record the fact that ExitLimit assumes NSW. When
it does not we can safely assume that the loop trip count is the
minimum ExitLimt across all subexpressions and loop exits.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_33@183246 91177308-0d34-0410-b5e6-96231b3b80d8