Refactor out LoopInfo computation so that it can be used by

other test cases.

Summary: Refactor out LoopInfo computation so that it can be
used by other test cases.

So i am changing this test proactively for later commit, which will use
this function.

Reviewers: sanjoy, hfinkel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28778

llvm-svn: 292250

llvm/unittests/Analysis/LoopInfoTest.cpp

@@ -15,6 +15,18 @@
 
 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;
@@ -25,52 +37,47 @@ static std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
 // 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";
-  
+      "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();
-  Function::iterator FI = F.begin();
-  FI++; // First basic block is entry - skip it.
-  BasicBlock *Header = &*FI++;
-  assert(Header->getName() == "for.cond");
-  Loop *L = LI.getLoopFor(Header);
+  runWithLoopInfo(*M, "foo", [&](Function &F, LoopInfo &LI) {
+    Function::iterator FI = F.begin();
+    // 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());
+    // 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;
-  }
+    // 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);
+    // We must have successfully found and set the loop id in the
+    // only latch the loop has.
+    EXPECT_TRUE(loopIDFoundAndSet);
+  });
 }