From 37eb38d3f8531115f17f4e829013ccb513952bad Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Thu, 21 Jul 2011 00:40:04 +0000
Subject: LSR crashes on an empty IVUsers list.

rdar://9786536


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135644 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/LoopStrengthReduce.cpp | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'lib/Transforms/Scalar')

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index e90b5bc..4598df0 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3740,6 +3740,9 @@ LSRInstance::LSRInstance(const TargetLowering *tli, Loop *l, Pass *P)
   OptimizeShadowIV();
   OptimizeLoopTermCond();
 
+  // If loop preparation eliminates all interesting IV users, bail.
+  if (IU.empty()) return;
+
   // Start collecting data and preparing for the solver.
   CollectInterestingTypesAndFactors();
   CollectFixupsAndInitialFormulae();
-- 
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