Index: llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp
+++ llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp
@@ -156,7 +156,6 @@
     AU.addPreservedID(LiveVariablesID);
     AU.addPreservedID(MachineLoopInfoID);
     AU.addPreservedID(MachineDominatorsID);
-    AU.setPreservesCFG();
     MachineFunctionPass::getAnalysisUsage(AU);
   }
 };
@@ -615,6 +614,38 @@
       if (LIS)
         LIS->RemoveMachineInstrFromMaps(*MI);
       MI->eraseFromParent();
+      if (MBB.size() == 1 && MBB.begin()->getOpcode() == AMDGPU::S_BRANCH) {
+        MachineBasicBlock *Succ = MBB.begin()->getOperand(0).getMBB();
+        SmallVector<MachineBasicBlock *, 2> Preds;
+        for (auto &Pred : MBB.predecessors()) {
+          Preds.push_back(Pred);
+        }
+        for (auto P : Preds) {
+          P->removeSuccessor(&MBB);
+          P->addSuccessor(Succ);
+          MachineBasicBlock::iterator I(P->getFirstInstrTerminator());
+          while (I != P->end()) {
+            if (I->isBranch()) {
+              if (TII->getBranchDestBlock(*I) == &MBB) {
+                I->getOperand(0).setMBB(Succ);
+                break;
+              }
+            }
+            I++;
+          }
+          if (I == P->end()) {
+            MachineInstr *Br =
+                BuildMI(P, DebugLoc(), TII->get(AMDGPU::S_BRANCH)).addMBB(Succ);
+            if (LIS)
+              LIS->InsertMachineInstrInMaps(*Br);
+          }
+        }
+        MBB.removeSuccessor(Succ);
+        MBB.eraseFromParent();
+        if (LIS) {
+          LIS->RemoveMachineInstrFromMaps(*MBB.begin());
+        }
+      }
     }
   }
 }
Index: llvm/test/CodeGen/AMDGPU/collapse-endcf.mir
===================================================================
--- llvm/test/CodeGen/AMDGPU/collapse-endcf.mir
+++ llvm/test/CodeGen/AMDGPU/collapse-endcf.mir
@@ -387,14 +387,12 @@
   ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
   ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
   ; GCN: bb.1:
-  ; GCN:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
+  ; GCN:   successors: %bb.2(0x40000000), %bb.5(0x40000000)
   ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
   ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
   ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
-  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
+  ; GCN:   S_CBRANCH_EXECZ %bb.5, implicit $exec
   ; GCN: bb.2:
-  ; GCN:   successors: %bb.3(0x80000000)
-  ; GCN: bb.3:
   ; GCN:   successors: %bb.5(0x80000000)
   ; GCN:   S_BRANCH %bb.5
   ; GCN: bb.4: