Index: lib/CodeGen/CodeGen.cpp
===================================================================
--- lib/CodeGen/CodeGen.cpp
+++ lib/CodeGen/CodeGen.cpp
@@ -58,6 +58,7 @@
   initializeMachineModuleInfoPass(Registry);
   initializeMachinePipelinerPass(Registry);
   initializeMachinePostDominatorTreePass(Registry);
+  initializeMachineRegionInfoPassPass(Registry);
   initializeMachineSchedulerPass(Registry);
   initializeMachineSinkingPass(Registry);
   initializeMachineVerifierPassPass(Registry);
Index: lib/CodeGen/MachineRegionInfo.cpp
===================================================================
--- lib/CodeGen/MachineRegionInfo.cpp
+++ lib/CodeGen/MachineRegionInfo.cpp
@@ -4,7 +4,7 @@
 #include "llvm/Analysis/RegionInfoImpl.h"
 #include "llvm/CodeGen/MachinePostDominators.h"
 
-#define DEBUG_TYPE "region"
+#define DEBUG_TYPE "machineregions"
 
 using namespace llvm;
 
@@ -86,6 +86,9 @@
   auto DF = &getAnalysis<MachineDominanceFrontier>();
 
   RI.recalculate(F, DT, PDT, DF);
+
+  DEBUG(RI.dump());
+
   return false;
 }
 
@@ -103,9 +106,10 @@
 
 void MachineRegionInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
-  AU.addRequiredTransitive<DominatorTreeWrapperPass>();
-  AU.addRequired<PostDominatorTreeWrapperPass>();
-  AU.addRequired<DominanceFrontierWrapperPass>();
+  AU.addRequired<MachineDominatorTree>();
+  AU.addRequired<MachinePostDominatorTree>();
+  AU.addRequired<MachineDominanceFrontier>();
+  MachineFunctionPass::getAnalysisUsage(AU);
 }
 
 void MachineRegionInfoPass::print(raw_ostream &OS, const Module *) const {
@@ -120,12 +124,12 @@
 
 char MachineRegionInfoPass::ID = 0;
 
-INITIALIZE_PASS_BEGIN(MachineRegionInfoPass, "regions",
+INITIALIZE_PASS_BEGIN(MachineRegionInfoPass, "machineregions",
                 "Detect single entry single exit regions", true, true)
 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(MachinePostDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(MachineDominanceFrontier)
-INITIALIZE_PASS_END(MachineRegionInfoPass, "regions",
+INITIALIZE_PASS_END(MachineRegionInfoPass, "machineregions",
                 "Detect single entry single exit regions", true, true)
 
 // Create methods available outside of this file, to use them
Index: test/CodeGen/MIR/Generic/machine-region-info.ll
===================================================================
--- /dev/null
+++ test/CodeGen/MIR/Generic/machine-region-info.ll
@@ -0,0 +1,76 @@
+; RUN: llc -stop-after virtregrewriter %s -o %t.mir
+; RUN: llc -run-pass=machineregions %t.mir -debug-only=machineregions 2>&1 | FileCheck %s
+
+define i32 @fun(i32 %a) {
+A:
+  %cmp0 = icmp eq i32 %a, 40
+  br i1 %cmp0, label %B, label %I
+
+B:
+  %cmp1 = icmp eq i32 %a, 1
+  br i1 %cmp1, label %C, label %H
+
+C:
+  %cmp2 = icmp eq i32 %a, 2
+  br i1 %cmp2, label %D, label %F
+
+D:
+  %cmp3 = icmp eq i32 %a, 90
+  br i1 %cmp3, label %E, label %F
+
+E:
+  call void @fun1(i32 100)
+  br label %F
+
+F:
+  %cmp4 = icmp eq i32 %a, 4
+  br i1 %cmp4, label %G, label %H
+
+G:
+  call void @fun1(i32 300)
+  br label %H
+
+H:
+  br label %P
+
+I:
+  %cmp5 = icmp eq i32 %a, 5
+  br i1 %cmp5, label %J, label %K
+
+J:
+  br label %L
+
+K:
+  call void @fun1(i32 400)
+  br label %L
+
+L:
+  %cmp6 = icmp eq i32 %a, 6
+  br i1 %cmp6, label %M, label %N
+
+M:
+  br label %O
+
+N:
+  call void @fun1(i32 500)
+  br label %O
+
+O:
+  br label %P
+
+P:
+  ret i32 %a
+}
+
+declare void @fun1(i32 %a)
+
+; CHECK: Region tree:
+; CHECK-NEXT: [0] A => <Function Return>
+; CHECK-NEXT:   [1] A => P
+; CHECK-NEXT:     [2] B => P
+; CHECK-NEXT:       [3] C => F
+; CHECK-NEXT:         [4] D => F
+; CHECK-NEXT:       [3] F => P
+; CHECK-NEXT:     [2] I => L
+; CHECK-NEXT:     [2] L => P
+; CHECK-NEXT: End region tree