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[IRGen] Put 'ret void' instead of unreachable for non swiftasync cc #39680

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Merged
merged 1 commit into from
Dec 7, 2021
Merged

[IRGen] Put 'ret void' instead of unreachable for non swiftasync cc #39680

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10 changes: 9 additions & 1 deletion lib/IRGen/GenCall.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4929,7 +4929,15 @@ void irgen::emitAsyncReturn(
arguments.push_back(arg);

Builder.CreateIntrinsicCall(llvm::Intrinsic::coro_end_async, arguments);
Builder.CreateUnreachable();

if (IGF.IGM.AsyncTailCallKind == llvm::CallInst::TCK_MustTail) {
Builder.CreateUnreachable();
} else {
// If target doesn't support musttail (e.g. WebAssembly), the function
// passed to coro.end.async can return control back to the caller.
// So use ret void instead of unreachable to allow it.
Builder.CreateRetVoid();
}
}

void irgen::emitAsyncReturn(IRGenFunction &IGF, AsyncContextLayout &asyncLayout,
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17 changes: 17 additions & 0 deletions test/IRGen/async/non_musttail_target.sil
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@@ -0,0 +1,17 @@
// Ensure that IRGen don't emit unreachable after coro.end.async for targets that don't support musttail call.
// RUN: %swift -disable-legacy-type-info -parse-stdlib -target wasm32-unknown-wasi %s -disable-llvm-optzns -disable-swift-specific-llvm-optzns -disable-objc-interop -module-name main -emit-ir -o - | %FileCheck %s
// REQUIRES: concurrency
// REQUIRES: CODEGENERATOR=WebAssembly

sil_stage canonical

import Builtin

sil @test_simple : $@async () -> () {
bb0:
%0 = tuple ()
return %0 : $()
// CHECK: call i1 (i8*, i1, ...) @llvm.coro.end.async
// CHECK-NOT: unreachable
// CHECK: ret void
}