diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
index 31491513bd96a1..a4f07806fbe362 100644
--- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
@@ -2914,10 +2914,7 @@ bool MachineBlockPlacement::repeatedlyTailDuplicateBlock(
   // duplicated into is still small enough to be duplicated again.
   // No need to call markBlockSuccessors in this case, as the blocks being
   // duplicated from here on are already scheduled.
-  // Note that DuplicatedToLPred always implies Removed.
-  while (DuplicatedToLPred) {
-    assert(Removed && "Block must have been removed to be duplicated into its "
-           "layout predecessor.");
+  while (DuplicatedToLPred && Removed) {
     MachineBasicBlock *DupBB, *DupPred;
     // The removal callback causes Chain.end() to be updated when a block is
     // removed. On the first pass through the loop, the chain end should be the
@@ -2956,8 +2953,7 @@ bool MachineBlockPlacement::repeatedlyTailDuplicateBlock(
 ///                          chosen in the given order due to unnatural CFG
 ///                          only needed if \p BB is removed and
 ///                          \p PrevUnplacedBlockIt pointed to \p BB.
-/// \p DuplicatedToLPred - True if the block was duplicated into LPred. Will
-///                        only be true if the block was removed.
+/// \p DuplicatedToLPred - True if the block was duplicated into LPred.
 /// \return  - True if the block was duplicated into all preds and removed.
 bool MachineBlockPlacement::maybeTailDuplicateBlock(
     MachineBasicBlock *BB, MachineBasicBlock *LPred,
diff --git a/llvm/test/CodeGen/X86/tail-dup-partial.ll b/llvm/test/CodeGen/X86/tail-dup-partial.ll
new file mode 100644
index 00000000000000..7825856dbd0f0f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/tail-dup-partial.ll
@@ -0,0 +1,85 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu  -O3 | FileCheck %s
+
+; Function Attrs: uwtable
+; When tail-duplicating during placement, we work backward from blocks with
+; multiple successors. In this case, the block dup1 gets duplicated into dup2
+; and if.then64, and then the block dup2 only gets duplicated into land.lhs.true.
+
+define void @partial_tail_dup(i1 %a1, i1 %a2, i32* %a4, i32* %a5, i8* %a6, i32 %a7) #0 align 2  !prof !1 {
+; CHECK-LABEL: partial_tail_dup:
+; CHECK:        # %bb.0: # %entry
+; CHECK-NEXT:   .p2align 4, 0x90
+; CHECK-NEXT:   .LBB0_1: # %for.cond
+; CHECK-NEXT:   # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:	  testb	$1, %dil
+; CHECK-NEXT:	  je	.LBB0_3
+; CHECK-NEXT:   # %bb.2: # %land.lhs.true
+; CHECK-NEXT:   # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT:	  movl	$10, (%rdx)
+; CHECK-NEXT:	  movl	$2, (%rcx)
+; CHECK-NEXT:	  testl	%r9d, %r9d
+; CHECK-NEXT:	  je	.LBB0_1
+; CHECK-NEXT:	  jmp	.LBB0_8
+; CHECK-NEXT:	  .p2align	4, 0x90
+; CHECK-NEXT:   .LBB0_6: # %dup2
+; CHECK-NEXT:   # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT:	  movl	$2, (%rcx)
+; CHECK-NEXT:	  testl	%r9d, %r9d
+; CHECK-NEXT:	  je	.LBB0_1
+; CHECK-NEXT:	  jmp	.LBB0_8
+; CHECK-NEXT:    .p2align 4, 0x90
+; CHECK-NEXT:  .LBB0_3: # %if.end56
+; CHECK-NEXT:    # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT:    testb $1, %sil
+; CHECK-NEXT:    je .LBB0_5
+; CHECK-NEXT:  # %bb.4: # %if.then64
+; CHECK-NEXT:    # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT:    movb $1, (%r8)
+; CHECK-NEXT:    testl %r9d, %r9d
+; CHECK-NEXT:    je .LBB0_1
+; CHECK-NEXT:    jmp .LBB0_8
+; CHECK-NEXT:  .LBB0_5: # %if.end70
+; CHECK-NEXT:    # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT:    movl $12, (%rdx)
+; CHECK-NEXT:    jne .LBB0_6  
+; CHECK-NEXT:  .LBB0_8: # %for.end
+; CHECK-NEXT:    retq
+entry:
+  br label %for.cond
+
+for.cond:                                      
+  br i1 %a1, label %land.lhs.true, label %if.end56
+
+land.lhs.true:                                   
+  store i32 10, i32* %a4, align 8
+  br label %dup2
+
+if.end56:                                        
+  br i1 %a2, label %if.then64, label %if.end70, !prof !2
+
+if.then64:                                       
+  store i8 1, i8* %a6, align 1
+  br label %dup1
+
+if.end70:                                        
+  store i32 12, i32* %a4, align 8
+  br i1 %a2, label %dup2, label %for.end
+
+dup2:                                            
+  store i32 2, i32* %a5, align 4
+  br label %dup1
+
+dup1:                                            
+  %val = load i32, i32* %a4, align 8
+  %switch = icmp ult i32 %a7, 1
+  br i1 %switch, label %for.cond, label %for.end, !prof !3
+
+for.end:                                         
+  ret void
+}
+
+attributes #0 = { uwtable }
+
+!1 = !{!"function_entry_count", i64 2}
+!2 = !{!"branch_weights", i32 5, i32 1}
+!3 = !{!"branch_weights", i32 5, i32 1}