From c6b0c4b9e2ba2b86a5ec96f76fcf1f0f281f12a6 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Wed, 10 Mar 2004 21:42:19 +0000
Subject: [PATCH] Fix PR284: [indvars] Induction variable analysis violates
 LLVM invariants

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12275 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/InductionVariable.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/Analysis/InductionVariable.cpp b/lib/Analysis/InductionVariable.cpp
index b6025294948..8f622973f96 100644
--- a/lib/Analysis/InductionVariable.cpp
+++ b/lib/Analysis/InductionVariable.cpp
@@ -136,10 +136,14 @@ InductionVariable::InductionVariable(PHINode *P, LoopInfo *LoopInfo): End(0) {
         if (Constant *CV = dyn_cast<Constant>(V))
           Step = ConstantExpr::get(Instruction::Sub, Zero, CV);
         else if (Instruction *I = dyn_cast<Instruction>(V)) {
+          BasicBlock::iterator InsertPt = I;
+          for (++InsertPt; isa<PHINode>(InsertPt); ++InsertPt)
+            /*empty*/;
           Step = BinaryOperator::create(Instruction::Sub, Zero, V,
-                                        V->getName()+".neg", I->getNext());
+                                        V->getName()+".neg", InsertPt);
 
         } else {
+          // Must be loop invariant
           Step = BinaryOperator::create(Instruction::Sub, Zero, V,
                                         V->getName()+".neg", 
                               Phi->getParent()->getParent()->begin()->begin());