The same code,but fpm make it wrong

Befor Add FPM:

define void @main() {
  %t = alloca i32, align 4
  store i32 1, i32* %t, align 4
  br label %loop

loop:                                             ; preds = %loopBody, %entry
  %t2 = load i32, i32* %t, align 4
  %0 = and i32 %t2, 1
  %1 = icmp eq i32 %0, 0
  br i1 %1, label %afterLoop, label %loopBody

loopBody:                                         ; preds = %loop
  br label %afterLoop
  br label %loop

afterLoop:                                        ; preds = %loop, %loopBody
  %t3 = load i32, i32* %t, align 4
  %calltmp = call void @test(i32 %t3)
  ret void

declare void @test(i32)

After add createCFGSimplification By call FPM->add(llvm::createCFGSimplificationPass())
It turns to

define void @main() {
  br label %loop

loop:                                             ; preds = %loop, %entry
  br void

with a Segmentation fault

You posted in MLIR but this seems like a pure LLVM issue?

Also can you provide a complete reproducer?