From 99cca7d3aa774d52b28f04bb0783747c038cda7a Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 1 Mar 2004 01:12:13 +0000
Subject: [PATCH] Disable tail duplication in a case that breaks on Olden/tsp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12021 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/TailDuplication.cpp | 4 ++++
 lib/Transforms/Utils/LowerInvoke.cpp      | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/Transforms/Scalar/TailDuplication.cpp b/lib/Transforms/Scalar/TailDuplication.cpp
index 315b90697cf..a3980b342c2 100644
--- a/lib/Transforms/Scalar/TailDuplication.cpp
+++ b/lib/Transforms/Scalar/TailDuplication.cpp
@@ -135,6 +135,10 @@ bool TailDup::canEliminateUnconditionalBranch(TerminatorInst *TI) {
       Instruction *User = cast<Instruction>(*UI);
       if (User->getParent() != Tail && User->getParent() != BB)
         return false;
+
+      // The 'swap' problem foils the tail duplication rewriting code.
+      if (isa<PHINode>(User) && User->getParent() == Tail)
+        return false;
     }
   return true;
 }
diff --git a/lib/Transforms/Utils/LowerInvoke.cpp b/lib/Transforms/Utils/LowerInvoke.cpp
index d42d0533f1c..24033f4876a 100644
--- a/lib/Transforms/Utils/LowerInvoke.cpp
+++ b/lib/Transforms/Utils/LowerInvoke.cpp
@@ -42,7 +42,7 @@ using namespace llvm;
 
 namespace {
   Statistic<> NumLowered("lowerinvoke", "Number of invoke & unwinds replaced");
-  cl::opt<bool> ExpensiveEHSupport("enable-correct-eh-support", 
+  cl::opt<bool> ExpensiveEHSupport("enable-correct-eh-support",
  cl::desc("Make the -lowerinvoke pass insert expensive, but correct, EH code"));
 
   class LowerInvoke : public FunctionPass {