From a784589f579de6f8a34e6bbfcf48ebba6b01c719 Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Mon, 28 Jul 2014 23:25:21 +0000
Subject: [PATCH] llvm-uselistorder: Add -num-shuffles option

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214144 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/Bitcode/use-list-order.ll                |  2 +-
 tools/llvm-uselistorder/llvm-uselistorder.cpp | 23 ++++++++++++++-----
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/test/Bitcode/use-list-order.ll b/test/Bitcode/use-list-order.ll
index 6a1fedc1ff4..ac7307b2711 100644
--- a/test/Bitcode/use-list-order.ll
+++ b/test/Bitcode/use-list-order.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-uselistorder < %s -preserve-bc-use-list-order
+; RUN: llvm-uselistorder < %s -preserve-bc-use-list-order -num-shuffles=5
 
 @a = global [4 x i1] [i1 0, i1 1, i1 0, i1 1]
 @b = alias i1* getelementptr ([4 x i1]* @a, i64 0, i64 2)
diff --git a/tools/llvm-uselistorder/llvm-uselistorder.cpp b/tools/llvm-uselistorder/llvm-uselistorder.cpp
index d86b592c928..edd9b395426 100644
--- a/tools/llvm-uselistorder/llvm-uselistorder.cpp
+++ b/tools/llvm-uselistorder/llvm-uselistorder.cpp
@@ -43,6 +43,11 @@ static cl::opt<std::string> InputFilename(cl::Positional,
 static cl::opt<bool> SaveTemps("save-temps", cl::desc("Save temp files"),
                                cl::init(false));
 
+static cl::opt<unsigned>
+    NumShuffles("num-shuffles",
+                cl::desc("Number of times to shuffle and verify use-lists"),
+                cl::init(1));
+
 namespace {
 
 struct TempFile {
@@ -370,13 +375,19 @@ int main(int argc, char **argv) {
     return 0;
   }
 
-  shuffleUseLists(*M);
-  if (!verifyBitcodeUseListOrder(*M))
-    report_fatal_error("bitcode use-list order changed");
+  for (unsigned I = 0, E = NumShuffles; I != E; ++I) {
+    DEBUG(dbgs() << "*** iteration: " << I << " ***\n");
+
+    // Shuffle with a different seed each time so that use-lists that aren't
+    // modified the first time are likely to be modified the next time.
+    shuffleUseLists(*M, I);
+    if (!verifyBitcodeUseListOrder(*M))
+      report_fatal_error("bitcode use-list order changed");
 
-  if (shouldPreserveAssemblyUseListOrder())
-    if (!verifyAssemblyUseListOrder(*M))
-      report_fatal_error("assembly use-list order changed");
+    if (shouldPreserveAssemblyUseListOrder())
+      if (!verifyAssemblyUseListOrder(*M))
+        report_fatal_error("assembly use-list order changed");
+  }
 
   return 0;
 }
-- 
2.34.1