Index: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -294,6 +294,30 @@
     }
   }
 
+  // If we're allowed to modify and the block ends in a unconditional branch
+  // which could simply fallthrough, remove the branch.  (Note: This case only
+  // matters when we can't understand the whole sequence, otherwise it's also
+  // handled by BranchFolding.cpp.)
+  if (AllowModify && isUncondBranchOpcode(LastOpc) &&
+      MBB.isLayoutSuccessor(getBranchDestBlock(*LastInst))) {
+    LastInst->eraseFromParent();
+    LastInst = SecondLastInst;
+    LastOpc = LastInst->getOpcode();
+    if (I == MBB.begin() || !isUnpredicatedTerminator(*--I)) {
+      assert(!isUncondBranchOpcode(LastOpc) && "should be covered by previous");
+
+      if (isCondBranchOpcode(LastOpc)) {
+        // Block ends with fall-through condbranch.
+        parseCondBranch(LastInst, TBB, Cond);
+        return false;
+      }
+      return true; // Can't handle indirect branch.
+    } else {
+      SecondLastInst = &*I;
+      SecondLastOpc = SecondLastInst->getOpcode();
+    }
+  }
+
   // If there are three terminators, we don't know what sort of block this is.
   if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(*--I))
     return true;
Index: llvm/test/CodeGen/AArch64/implicit-null-check.ll
===================================================================
--- llvm/test/CodeGen/AArch64/implicit-null-check.ll
+++ llvm/test/CodeGen/AArch64/implicit-null-check.ll
@@ -11,8 +11,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp0:
 ; CHECK-NEXT:    ldr w0, [x0] // on-fault: .LBB0_2
-; CHECK-NEXT:    b .LBB0_1
-; CHECK-NEXT:  .LBB0_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB0_2: // %is_null
 ; CHECK-NEXT:    mov w0, #42
@@ -35,8 +34,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp1:
 ; CHECK-NEXT:    ldr w0, [x0] // on-fault: .LBB1_2
-; CHECK-NEXT:    b .LBB1_1
-; CHECK-NEXT:  .LBB1_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB1_2: // %is_null
 ; CHECK-NEXT:    mov w0, #42
@@ -58,8 +56,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp2:
 ; CHECK-NEXT:    ldr w0, [x0] // on-fault: .LBB2_2
-; CHECK-NEXT:    b .LBB2_1
-; CHECK-NEXT:  .LBB2_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB2_2: // %is_null
 ; CHECK-NEXT:    mov w0, #42
@@ -130,8 +127,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp3:
 ; CHECK-NEXT:    ldrb w0, [x0] // on-fault: .LBB5_2
-; CHECK-NEXT:    b .LBB5_1
-; CHECK-NEXT:  .LBB5_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB5_2: // %is_null
 ; CHECK-NEXT:    mov w0, #42
@@ -182,8 +178,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp4:
 ; CHECK-NEXT:    ldr w0, [x0, #128] // on-fault: .LBB7_2
-; CHECK-NEXT:    b .LBB7_1
-; CHECK-NEXT:  .LBB7_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB7_2: // %is_null
 ; CHECK-NEXT:    mov w0, #42
@@ -206,8 +201,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp5:
 ; CHECK-NEXT:    ldr w8, [x0] // on-fault: .LBB8_2
-; CHECK-NEXT:    b .LBB8_1
-; CHECK-NEXT:  .LBB8_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    add w0, w8, w1
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB8_2: // %is_null
@@ -233,8 +227,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp6:
 ; CHECK-NEXT:    ldr w8, [x0] // on-fault: .LBB9_2
-; CHECK-NEXT:    b .LBB9_1
-; CHECK-NEXT:  .LBB9_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    udiv w9, w1, w2
 ; CHECK-NEXT:    add w0, w8, w9
 ; CHECK-NEXT:    ret
@@ -289,8 +282,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp7:
 ; CHECK-NEXT:    ldr w8, [x0] // on-fault: .LBB11_2
-; CHECK-NEXT:    b .LBB11_1
-; CHECK-NEXT:  .LBB11_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    add w9, w0, w1
 ; CHECK-NEXT:    add w8, w9, w8
 ; CHECK-NEXT:    add w0, w8, #4 // =4
@@ -417,8 +409,7 @@
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:  .Ltmp8:
 ; CHECK-NEXT:    ldur w0, [x0, #-128] // on-fault: .LBB16_2
-; CHECK-NEXT:    b .LBB16_1
-; CHECK-NEXT:  .LBB16_1: // %not_null
+; CHECK-NEXT:  // %bb.1: // %not_null
 ; CHECK-NEXT:    ret
 ; CHECK-NEXT:  .LBB16_2: // %is_null
 ; CHECK-NEXT:    mov w0, #42