Use a test fixture for LoopInfoTest.

[trentxintong]

Summary

I am about to add some new tests to the file in a later patch, but all the
tests in the file have to all be using TEST_F or none.

So i am changing this test proactively for later commit.

Plus the later patch will use the same fixture.

[sanjoy]

unittests/Analysis/LoopInfoTest.cpp

27

Not sure what you're getting out of making this a fixture. Why can't DT adn LI live as locals within runWithLoopInfo?

[trentxintong]

Address comments.

[sanjoy]

unittests/Analysis/LoopInfoTest.cpp

26

Why unique_ptr? Why not just:

DominatorTree DT(F);
LoopInfo LI(DT);

?

Also: why do you need the fixture at all? Why not just have runWithLoopInfo be a (static) free function.

[trentxintong]

We do not actually need a test fixture for this.

[sanjoy]

LGTM

unittests/Analysis/LoopInfoTest.cpp

21

Please clang-format.

[trentxintong]

Running clang-format.

unittests/Analysis/LoopInfoTest.cpp

 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/Support/SourceMgr.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
 
+/// Build the loop info for the function and run the Test.
+static void
+runWithLoopInfo(Module &M, StringRef FuncName,
+                function_ref<void(Function &F, LoopInfo &LI)> Test) {
+  auto *F = M.getFunction(FuncName);
+  ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
+  // Compute the dominator tree and the loop info for the function.
+  DominatorTree DT(*F);
+  LoopInfo LI(DT);
+  Test(*F, LI);
+}
+
 static std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
                                               const char *ModuleStr) {
   SMDiagnostic Err;
   return parseAssemblyString(ModuleStr, Err, Context);
 }
 
 // This tests that for a loop with a single latch, we get the loop id from
 // its only latch, even in case the loop may not be in a simplified form.
 TEST(LoopInfoTest, LoopWithSingleLatch) {
   const char *ModuleStr =
-         "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
-         "define void @foo(i32 %n) {\n"
-         "entry:\n"
-         "  br i1 undef, label %for.cond, label %for.end\n"
-         "for.cond:\n"
-         "  %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]\n"
-         "  %cmp = icmp slt i32 %i.0, %n\n"
-         "  br i1 %cmp, label %for.inc, label %for.end\n"
-         "for.inc:\n"
-         "  %inc = add nsw i32 %i.0, 1\n"
-         "  br label %for.cond, !llvm.loop !0\n"
-         "for.end:\n"
-         "  ret void\n"
-         "}\n"
-         "!0 = distinct !{!0, !1}\n"
-         "!1 = !{!\"llvm.loop.distribute.enable\", i1 true}\n";
-  
   // Parse the module.
   LLVMContext Context;
   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 
-  // Build the dominator tree and loop info.
-  DominatorTree DT;
-  DT.recalculate(*M->begin());
-  LoopInfo LI;
-  LI.analyze(DT);
-
-  Function &F = *M->begin();
+  runWithLoopInfo(*M, "foo", [&](Function &F, LoopInfo &LI) {
     Function::iterator FI = F.begin();
-  FI++; // First basic block is entry - skip it.
-  BasicBlock *Header = &*FI++;
+    // First basic block is entry - skip it.
+    BasicBlock *Header = &*(++FI);
     assert(Header->getName() == "for.cond");
     Loop *L = LI.getLoopFor(Header);
 
     // This loop is not in simplified form.
     EXPECT_FALSE(L->isLoopSimplifyForm());
 
     // Analyze the loop metadata id.
     bool loopIDFoundAndSet = false;
     // Try to get and set the metadata id for the loop.
     if (MDNode *D = L->getLoopID()) {
       L->setLoopID(D);
       loopIDFoundAndSet = true;
     }
 
     // We must have successfully found and set the loop id in the
     // only latch the loop has.
     EXPECT_TRUE(loopIDFoundAndSet);
+  });
 }