From 36a07daabd1919d6c12b8f55b101d54c3d7171cd Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Sat, 7 Jul 2007 20:13:57 +0000
Subject: [PATCH] Fix an error where ANTIC_OUT was ending up with more than one
 expression of the same value number.  This fixes an infinite loop on
 444.namd.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37967 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/GVNPRE.cpp                   |  2 +-
 .../Transforms/GVNPRE/2007-07-07-AnticOutUnique.ll | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 test/Transforms/GVNPRE/2007-07-07-AnticOutUnique.ll

diff --git a/lib/Transforms/Scalar/GVNPRE.cpp b/lib/Transforms/Scalar/GVNPRE.cpp
index 0661c94dbd7..44846cb0df4 100644
--- a/lib/Transforms/Scalar/GVNPRE.cpp
+++ b/lib/Transforms/Scalar/GVNPRE.cpp
@@ -1370,7 +1370,7 @@ unsigned GVNPRE::buildsets_anticin(BasicBlock* BB,
     unsigned num = VN.lookup_or_add(*I);
     numbers.resize(VN.size());
     
-    if (isa<Instruction>(*I)) {
+    if (isa<Instruction>(*I) && !numbers.test(num)) {
       anticIn.insert(*I);
       numbers.set(num);
     }
diff --git a/test/Transforms/GVNPRE/2007-07-07-AnticOutUnique.ll b/test/Transforms/GVNPRE/2007-07-07-AnticOutUnique.ll
new file mode 100644
index 00000000000..2a7e49c6cd9
--- /dev/null
+++ b/test/Transforms/GVNPRE/2007-07-07-AnticOutUnique.ll
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | opt -gvnpre | llvm-dis
+	%"struct.ObjectArena<char>" = type { i32, i32, %"struct.ResizeArray<char*>", i8*, i8* }
+	%"struct.ResizeArray<char*>" = type { i32 (...)**, %"struct.ResizeArrayRaw<char*>"* }
+	%"struct.ResizeArrayRaw<char*>" = type { i8**, i8*, i32, i32, i32, float, i32 }
+
+define void @_ZN11ObjectArenaIcED1Ev(%"struct.ObjectArena<char>"* %this) {
+entry:
+	br label %cond_true21
+
+cond_true21:		; preds = %cond_true21, %entry
+	%tmp215.0 = phi %"struct.ResizeArray<char*>"* [ null, %entry ], [ null, %cond_true21 ]		; <%"struct.ResizeArray<char*>"*> [#uses=1]
+	%tmp2.i2 = getelementptr %"struct.ResizeArray<char*>"* %tmp215.0, i32 0, i32 1		; <%"struct.ResizeArrayRaw<char*>"**> [#uses=0]
+	br label %cond_true21
+}