diff --git a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
--- a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp
@@ -156,13 +156,6 @@
         << "Deletion requires Loop with preheader and dedicated exits.\n");
     return LoopDeletionResult::Unmodified;
   }
-  // We can't remove loops that contain subloops.  If the subloops were dead,
-  // they would already have been removed in earlier executions of this pass.
-  if (L->begin() != L->end()) {
-    LLVM_DEBUG(dbgs() << "Loop contains subloops.\n");
-    return LoopDeletionResult::Unmodified;
-  }
-
 
   BasicBlock *ExitBlock = L->getUniqueExitBlock();
 
diff --git a/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll b/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
--- a/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
+++ b/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
@@ -10,24 +10,7 @@
 define void @test1(i64 %N, i64 %M, %pair_t* %ptr) willreturn {
 ; CHECK-LABEL: @test1(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    br label [[OUTER_HEADER:%.*]]
-; CHECK:       outer.header:
-; CHECK-NEXT:    [[OUTER_IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[OUTER_IV_NEXT:%.*]], [[OUTER_LATCH:%.*]] ]
-; CHECK-NEXT:    br label [[INNER:%.*]]
-; CHECK:       inner:
-; CHECK-NEXT:    [[INNER_IV:%.*]] = phi i64 [ 0, [[OUTER_HEADER]] ], [ [[INNER_IV_NEXT:%.*]], [[INNER]] ]
-; CHECK-NEXT:    [[GEP:%.*]] = getelementptr [[PAIR_T:%.*]], %pair_t* [[PTR:%.*]], i64 [[INNER_IV]]
-; CHECK-NEXT:    [[P:%.*]] = load [[PAIR_T]], %pair_t* [[GEP]], align 4
-; CHECK-NEXT:    [[V_0:%.*]] = extractvalue [[PAIR_T]] [[P]], 0
-; CHECK-NEXT:    [[V_1:%.*]] = extractvalue [[PAIR_T]] [[P]], 1
-; CHECK-NEXT:    [[INNER_EC:%.*]] = icmp ult i64 [[V_0]], [[V_1]]
-; CHECK-NEXT:    [[INNER_IV_NEXT]] = add i64 [[INNER_IV]], 1
-; CHECK-NEXT:    br i1 [[INNER_EC]], label [[OUTER_LATCH]], label [[INNER]]
-; CHECK:       outer.latch:
-; CHECK-NEXT:    [[LCSSA:%.*]] = phi i64 [ [[V_1]], [[INNER]] ]
-; CHECK-NEXT:    [[OUTER_EC:%.*]] = icmp ult i64 [[OUTER_IV]], [[LCSSA]]
-; CHECK-NEXT:    [[OUTER_IV_NEXT]] = add i64 [[OUTER_IV]], 1
-; CHECK-NEXT:    br i1 [[OUTER_EC]], label [[EXIT:%.*]], label [[OUTER_HEADER]]
+; CHECK-NEXT:    br label [[EXIT:%.*]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
 ;
diff --git a/llvm/test/Transforms/LoopDeletion/unreachable-loops.ll b/llvm/test/Transforms/LoopDeletion/unreachable-loops.ll
--- a/llvm/test/Transforms/LoopDeletion/unreachable-loops.ll
+++ b/llvm/test/Transforms/LoopDeletion/unreachable-loops.ll
@@ -244,22 +244,15 @@
 
 ; Delete a loop (L2) which has subloop (L3).
 ; Here we delete loop L2, but leave L3 as is.
-; FIXME: Can delete L3 as well, by iteratively going backward through the single
-; predecessor of L3 until we reach L1's block that guarantees L3 is never
-; executed.
 define void @test9(i64 %n) {
 ; CHECK-LABEL: test9
-; CHECK-LABEL: L2.preheader:
-; CHECK-NEXT: br label %L3.preheader
-; CHECK-NOT: L2:
-; CHECK-LABEL: L3.preheader:
-; CHECK-NEXT: %y.L2.lcssa = phi i64 [ undef, %L2.preheader ]
-; CHECK-NEXT: br label %L3
-; CHECK-LABEL: L3:
-; CHECK: br i1 %cond2, label %L3, label %L1.loopexit
+; CHECK-LABEL: entry:
+; CHECK-NEXT:    br label %exit
+; CHECK-LABEL: exit:
+; CHECK-NEXT:    ret  void
 ; REMARKS-LABEL: Function: test9
 ; REMARKS: Loop deleted because it never executes
-entry: 
+entry:
   br label %L1
 
 L1:
@@ -283,12 +276,12 @@
 ; We cannot delete L3 because of call within it.
 ; Since L3 is not deleted, and entirely contained within L2, L2 is also not
 ; deleted.
-; FIXME: We can delete unexecutable loops having
-; subloops contained entirely within them.
 define void @test10(i64 %n) {
 ; CHECK-LABEL: test10
-; CHECK: L2:
-; CHECK: L3:
+; CHECK-LABEL: entry:
+; CHECK-NEXT:   br label %exit
+; CHECK-LABEL: exit:
+; CHECK-NEXT:    ret void
 entry: 
   br label %L1
 
diff --git a/llvm/test/Transforms/LoopDeletion/update-scev.ll b/llvm/test/Transforms/LoopDeletion/update-scev.ll
--- a/llvm/test/Transforms/LoopDeletion/update-scev.ll
+++ b/llvm/test/Transforms/LoopDeletion/update-scev.ll
@@ -48,6 +48,7 @@
 
 for.inc11:                                        ; preds = %for.body6
   %and.lcssa = phi i32 [ %and, %for.body6 ]
+  call void @sideeffect(i32 %and.lcssa)
   %inc12 = add nsw i32 %val, 1
   %tobool = icmp eq i32 %inc12, 0
   br i1 %tobool, label %for.cond14, label %for.body
@@ -56,6 +57,8 @@
   br i1 undef, label %for.cond, label %for.cond14
 }
 
+declare void @sideeffect(i32)
+
 ; LoopDeletion removes the loop %for.body7.1. Make sure %inc.lcssa.1 in the loop
 ; exit block is correctly invalidated.