From 6f34e317e956da45a8015fe89e4b2ce4d7814fc3 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 19 Jan 2009 21:20:34 +0000
Subject: Fix PR3353, infinitely jump threading an infinite loop make from
 switches.

llvm-svn: 62529
---
 llvm/lib/Transforms/Scalar/JumpThreading.cpp | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'llvm/lib')

diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 94d33aa7879..f96fc208ae1 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -419,6 +419,11 @@ bool JumpThreading::ProcessBranchOnDuplicateCond(BasicBlock *PredBB,
 /// switches out of repeated 'if' conditions.
 bool JumpThreading::ProcessSwitchOnDuplicateCond(BasicBlock *PredBB,
                                                  BasicBlock *DestBB) {
+  // Can't thread edge to self.
+  if (PredBB == DestBB)
+    return false;
+  
+  
   SwitchInst *PredSI = cast<SwitchInst>(PredBB->getTerminator());
   SwitchInst *DestSI = cast<SwitchInst>(DestBB->getTerminator());
 
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