Make RandomNumberGenerator compatible with <random>

LLVM's RandomNumberGenerator wasn't compatible with
the random distribution from <random>.

Fixes PR25105

Patch by: Serge Guelton <serge.guelton@telecom-bretagne.eu>

Differential Revision: https://reviews.llvm.org/D25443

llvm-svn: 283854

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/unittests/IR/ModuleTest.cpp b/llvm/unittests/IR/ModuleTest.cpp
index c5f0bcb08f3..043ea04a0c1 100644
--- a/llvm/unittests/IR/ModuleTest.cpp
+++ b/llvm/unittests/IR/ModuleTest.cpp
@@ -9,8 +9,11 @@
 
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/RandomNumberGenerator.h"
 #include "gtest/gtest.h"
 
+#include <random>
+
 using namespace llvm;
 
 namespace {
@@ -45,4 +48,28 @@ TEST(ModuleTest, sortGlobalsByName) {
   }
 }
 
+TEST(ModuleTest, randomNumberGenerator) {
+  LLVMContext Context;
+  static char ID;
+  struct DummyPass : ModulePass {
+    DummyPass() : ModulePass(ID) {}
+    bool runOnModule(Module &) { return true; }
+  } DP;
+
+  Module M("R", Context);
+
+  std::uniform_int_distribution<int> dist;
+  constexpr std::size_t NBCheck = 10;
+
+  std::array<int, NBCheck> RandomStreams[2];
+  for (auto &RandomStream : RandomStreams) {
+    std::unique_ptr<RandomNumberGenerator> RNG{M.createRNG(&DP)};
+    std::generate(RandomStream.begin(), RandomStream.end(),
+                  [&]() { return dist(*RNG); });
+  }
+
+  EXPECT_TRUE(std::equal(RandomStreams[0].begin(), RandomStreams[0].end(),
+                         RandomStreams[1].begin()));
+}
+
 } // end namespace