diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -882,6 +882,7 @@
   addPass(createSILowerI1CopiesPass());
   addPass(createSIFixupVectorISelPass());
   addPass(createSIAddIMGInitPass());
+  addPass(&UnreachableMachineBlockElimID);
   return false;
 }
 
diff --git a/llvm/test/CodeGen/AMDGPU/lcssa-optnone.ll b/llvm/test/CodeGen/AMDGPU/lcssa-optnone.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/lcssa-optnone.ll
@@ -0,0 +1,25 @@
+; RUN: llc -march=amdgcn -O0 -o - %s | FileCheck %s
+
+; CHECK-LABEL: non_uniform_loop
+define amdgpu_kernel void @non_uniform_loop(float addrspace(1)* %array) {
+entry:
+  %w = tail call i32 @llvm.amdgcn.workitem.id.x()
+  br label %for.cond
+
+for.cond:
+  %i = phi i32 [0, %entry], [%i.next, %for.inc]
+  %cmp = icmp ult i32 %i, %w
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:
+  br label %for.inc
+
+for.inc:
+  %i.next = add i32 %i, 1
+  br label %for.cond
+
+for.end:
+  ret void
+}
+
+declare i32 @llvm.amdgcn.workitem.id.x()