[PGO] Fixed non-determinism with DenseSet storing function importing info.

Summary:
r296498 introduced a DenseSet to store function importing info.

Using this container causes a test failure in
test/Transform/SampleProfile/import.ll when in Reverse Iteration mode.

This patch orders IDs before iterating through this container.

Reviewers: danielcdh, mgrang

Reviewed By: danielcdh

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37246

llvm-svn: 312012

1 files changed, 7 insertions, 2 deletions

diff --git a/llvm/lib/IR/MDBuilder.cpp b/llvm/lib/IR/MDBuilder.cpp
index b9c4f482adf..84bad318591 100644
--- a/llvm/lib/IR/MDBuilder.cpp
+++ b/llvm/lib/IR/MDBuilder.cpp
@@ -62,9 +62,14 @@ MDNode *MDBuilder::createFunctionEntryCount(
   SmallVector<Metadata *, 8> Ops;
   Ops.push_back(createString("function_entry_count"));
   Ops.push_back(createConstant(ConstantInt::get(Int64Ty, Count)));
-  if (Imports)
-    for (auto ID : *Imports)
+  if (Imports) {
+    SmallVector<GlobalValue::GUID, 2> OrderID(Imports->begin(), Imports->end());
+    std::stable_sort(OrderID.begin(), OrderID.end(),
+      [] (GlobalValue::GUID A, GlobalValue::GUID B) {
+        return A < B;});
+    for (auto ID : OrderID)
       Ops.push_back(createConstant(ConstantInt::get(Int64Ty, ID)));
+  }
   return MDNode::get(Context, Ops);
 }