From: Chris Lattner <sabre@nondot.org>
Date: Fri, 25 Apr 2003 23:14:19 +0000 (+0000)
Subject: Fix a bug that occurred when removing the last predecessor INTO an
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=02a78cf7eacf97f2c9584e29d02f77612aead35f;p=oota-llvm.git

Fix a bug that occurred when removing the last predecessor INTO an
infinite loop


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5953 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index 04f4e1cfc0d..d04e5546162 100644
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -186,7 +186,11 @@ void BasicBlock::removePredecessor(BasicBlock *Pred) {
 
       // If the PHI _HAD_ two uses, replace PHI node with its now *single* value
       if (max_idx == 2) {
-	PN->replaceAllUsesWith(PN->getOperand(0));
+        if (PN->getOperand(0) != PN)
+          PN->replaceAllUsesWith(PN->getOperand(0));
+        else
+          // We are left with an infinite loop with no entries: kill the PHI.
+          PN->replaceAllUsesWith(Constant::getNullValue(PN->getType()));
         getInstList().pop_front();    // Remove the PHI node
       }