; Tests that coro-split will convert coro.resume followed by a suspend to a
; musttail call.
; RUN: opt < %s -passes='cgscc(coro-split),simplifycfg,early-cse' -S | FileCheck %s

define void @f() #0 {
entry:
  %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
  %alloc = call i8* @malloc(i64 16) #3
  %vFrame = call noalias nonnull i8* @llvm.coro.begin(token %id, i8* %alloc)

  %save = call token @llvm.coro.save(i8* null)
  %addr1 = call i8* @llvm.coro.subfn.addr(i8* null, i8 0)
  %pv1 = bitcast i8* %addr1 to void (i8*)*
  call fastcc void %pv1(i8* null)

  %suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
  switch i8 %suspend, label %exit [
    i8 0, label %await.suspend
    i8 1, label %exit
  ]
await.suspend:
  %save2 = call token @llvm.coro.save(i8* null)
  %br0 = call i8 @switch_result()
  switch i8 %br0, label %unreach [
    i8 0, label %await.resume3
    i8 1, label %await.resume1
    i8 2, label %await.resume2
  ]
await.resume1:
  %hdl = call i8* @g()
  %addr2 = call i8* @llvm.coro.subfn.addr(i8* %hdl, i8 0)
  %pv2 = bitcast i8* %addr2 to void (i8*)*
  call fastcc void %pv2(i8* %hdl)
  br label %final.suspend
await.resume2:
  %hdl2 = call i8* @h()
  %addr3 = call i8* @llvm.coro.subfn.addr(i8* %hdl2, i8 0)
  %pv3 = bitcast i8* %addr3 to void (i8*)*
  call fastcc void %pv3(i8* %hdl2)
  br label %final.suspend
await.resume3:
  %addr4 = call i8* @llvm.coro.subfn.addr(i8* null, i8 0)
  %pv4 = bitcast i8* %addr4 to void (i8*)*
  call fastcc void %pv4(i8* null)
  br label %final.suspend
final.suspend:
  %suspend2 = call i8 @llvm.coro.suspend(token %save2, i1 false)
  switch i8 %suspend2, label %exit [
    i8 0, label %pre.exit
    i8 1, label %exit
  ]
pre.exit:
  br label %exit
exit:
  call i1 @llvm.coro.end(i8* null, i1 false)
  ret void
unreach:
  unreachable
}

; Verify that in the initial function resume is not marked with musttail.
; CHECK-LABEL: @f(
; CHECK: %[[addr1:.+]] = call i8* @llvm.coro.subfn.addr(i8* null, i8 0)
; CHECK-NEXT: %[[pv1:.+]] = bitcast i8* %[[addr1]] to void (i8*)*
; CHECK-NOT: musttail call fastcc void %[[pv1]](i8* null)

; Verify that in the resume part resume call is marked with musttail.
; CHECK-LABEL: @f.resume(
; CHECK: %[[hdl:.+]] = call i8* @g()
; CHECK-NEXT: %[[addr2:.+]] = call i8* @llvm.coro.subfn.addr(i8* %[[hdl]], i8 0)
; CHECK-NEXT: %[[pv2:.+]] = bitcast i8* %[[addr2]] to void (i8*)*
; CHECK-NEXT: musttail call fastcc void %[[pv2]](i8* %[[hdl]])
; CHECK-NEXT: ret void
; CHECK: %[[hdl2:.+]] = call i8* @h()
; CHECK-NEXT: %[[addr3:.+]] = call i8* @llvm.coro.subfn.addr(i8* %[[hdl2]], i8 0)
; CHECK-NEXT: %[[pv3:.+]] = bitcast i8* %[[addr3]] to void (i8*)*
; CHECK-NEXT: musttail call fastcc void %[[pv3]](i8* %[[hdl2]])
; CHECK-NEXT: ret void
; CHECK: %[[addr4:.+]] = call i8* @llvm.coro.subfn.addr(i8* null, i8 0)
; CHECK-NEXT: %[[pv4:.+]] = bitcast i8* %[[addr4]] to void (i8*)*
; CHECK-NEXT: musttail call fastcc void %[[pv4]](i8* null)
; CHECK-NEXT: ret void



declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*) #1
declare i1 @llvm.coro.alloc(token) #2
declare i64 @llvm.coro.size.i64() #3
declare i8* @llvm.coro.begin(token, i8* writeonly) #2
declare token @llvm.coro.save(i8*) #2
declare i8* @llvm.coro.frame() #3
declare i8 @llvm.coro.suspend(token, i1) #2
declare i8* @llvm.coro.free(token, i8* nocapture readonly) #1
declare i1 @llvm.coro.end(i8*, i1) #2
declare i8* @llvm.coro.subfn.addr(i8* nocapture readonly, i8) #1
declare i8* @malloc(i64)
declare i8 @switch_result()
declare i8* @g()
declare i8* @h()

attributes #0 = { presplitcoroutine }
attributes #1 = { argmemonly nounwind readonly }
attributes #2 = { nounwind }
attributes #3 = { nounwind readnone }