Crash with label with break in a switch case

[ChuanqiXu9]

Reproducer:

void action1();
void action2();
void double_label(int v) {
  switch (v) {
    default:
        action1();
      label:
        action2();
        break;
  }
}

Diagnostic message:

loc("/disk2/workspace.xuchuanqi/clangir/clang/test/CIR/CodeGen/tmp.c":10:7): error: operation with block successors must terminate its parent block
fatal error: error in backend: CIR codegen: module verification error before running CIR passes

It looks like the it generates the break instruction in the wrong place:

      "cir.switch"(%1) <{cases = [#cir.case<value = [], kind = 1 : i32>]}> ({
        %2 = "cir.get_global"() <{name = @action1}> : () -> !cir.ptr<!cir.func<!void (...)>> loc(#loc24)
        %3 = "cir.cast"(%2) <{kind = 4 : i32}> : (!cir.ptr<!cir.func<!void (...)>>) -> !cir.ptr<!cir.func<!void ()>> loc(#loc24)
        "cir.call"(%3) <{ast = #cir.call.expr.ast, calling_conv = 1 : i32, extra_attrs = #fn_attr}> ({
        }) : (!cir.ptr<!cir.func<!void ()>>) -> () loc(#loc13)
        "cir.br"()[^bb1] : () -> () loc(#loc15) ; problematic
        "cir.break"() : () -> () loc(#loc16)
      ^bb1:  // pred: ^bb0
        "cir.label"() <{label = "label"}> : () -> () loc(#loc15)
        %4 = "cir.get_global"() <{name = @action2}> : () -> !cir.ptr<!cir.func<!void (...)>> loc(#loc25)
        %5 = "cir.cast"(%4) <{kind = 4 : i32}> : (!cir.ptr<!cir.func<!void (...)>>) -> !cir.ptr<!cir.func<!void ()>> loc(#loc25)
        "cir.call"(%5) <{ast = #cir.call.expr.ast, calling_conv = 1 : i32, extra_attrs = #fn_attr}> ({
        }) : (!cir.ptr<!cir.func<!void ()>>) -> () loc(#loc17)
        "cir.yield"() : () -> () loc(#loc10)
      }) : (!s32i) -> () loc(#loc10)

[bcardosolopes]

Adding a reference to this to our switch issues umbrella: #666

[bcardosolopes]

It's possible this is related to #528