llvm/test/Transforms/Coroutines/coro-split-musttail.ll
Gor Nishanov 8970bfadd2 [coroutines] Add support for symmetric control transfer (musttail on coro.resumes followed by a suspend)
Summary:
Add musttail to any resume instructions that is immediately followed by a
suspend (i.e. ret). We do this even in -O0 to support guaranteed tail call
for symmetrical coroutine control transfer (C++ Coroutines TS extension).
This transformation is done only in the resume part of the coroutine that has
identical signature and calling convention as the coro.resume call.

Reviewers: GorNishanov

Reviewed By: GorNishanov

Subscribers: EricWF, majnemer, llvm-commits

Differential Revision: https://reviews.llvm.org/D37125

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311751 91177308-0d34-0410-b5e6-96231b3b80d8
2017-08-25 02:25:10 +00:00

61 lines
2.2 KiB
LLVM

; Tests that coro-split will convert coro.resume followed by a suspend to a
; musttail call.
; RUN: opt < %s -coro-split -S | FileCheck %s
define void @f() "coroutine.presplit"="1" {
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.ready
i8 1, label %exit
]
await.ready:
%save2 = call token @llvm.coro.save(i8* null)
%addr2 = call i8* @llvm.coro.subfn.addr(i8* null, i8 0)
%pv2 = bitcast i8* %addr2 to void (i8*)*
call fastcc void %pv2(i8* null)
%suspend2 = call i8 @llvm.coro.suspend(token %save2, i1 false)
switch i8 %suspend2, label %exit [
i8 0, label %exit
i8 1, label %exit
]
exit:
call i1 @llvm.coro.end(i8* null, i1 false)
ret void
}
; 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: %[[addr2:.+]] = call i8* @llvm.coro.subfn.addr(i8* null, i8 0)
; CHECK-NEXT: %[[pv2:.+]] = bitcast i8* %[[addr2]] to void (i8*)*
; CHECK-NEXT: musttail call fastcc void %[[pv2]](i8* null)
; CHECK-NEXT: ret void
declare token @llvm.coro.id(i32, i8* readnone, i8* nocapture readonly, i8*)
declare i1 @llvm.coro.alloc(token) #3
declare i64 @llvm.coro.size.i64() #5
declare i8* @llvm.coro.begin(token, i8* writeonly) #3
declare token @llvm.coro.save(i8*) #3
declare i8* @llvm.coro.frame() #5
declare i8 @llvm.coro.suspend(token, i1) #3
declare i8* @llvm.coro.free(token, i8* nocapture readonly) #2
declare i1 @llvm.coro.end(i8*, i1) #3
declare i8* @llvm.coro.subfn.addr(i8* nocapture readonly, i8) #5
declare i8* @malloc(i64)