[llvm] [DSE] Defer alloca store elimination for CoroSplit (PR #133918)

[Nikita Popov via llvm-commits]

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@@ -0,0 +1,41 @@
+; Test that store-load operation that crosses suspension point will not be eliminated by DSE before CoroSplit
+; RUN: opt < %s -passes='dse,verify' -S | FileCheck %s
+
+define void @fn(ptr align 8 %0) presplitcoroutine {
+  %2 = alloca ptr, align 8
+  %3 = alloca i8, align 1
+  %4 = call token @llvm.coro.id(i32 16, ptr %2, ptr @fn, ptr null)
+  %5 = call ptr @llvm.coro.begin(token %4, ptr null)
+  %6 = call ptr @malloc(i64 1)
+  call void @llvm.lifetime.start.p0(i64 8, ptr %2)
+  store ptr %6, ptr %2, align 8
+  %7 = call token @llvm.coro.save(ptr null)
+  call void @llvm.coro.await.suspend.void(ptr %3, ptr %5, ptr @await_suspend_wrapper_void)
+  %8 = call i8 @llvm.coro.suspend(token %7, i1 false)
+  %9 = icmp ule i8 %8, 1
+  br i1 %9, label %10, label %11
+
+10:
+  call void @llvm.lifetime.end.p0(i64 8, ptr %2)
+  br label %11
+
+11:
+  %12 = call i1 @llvm.coro.end(ptr null, i1 false, token none)
+  %13 = load ptr, ptr %2, align 8
+  store ptr %13, ptr %0, align 8
+; store when suspend, load when resume
+; CHECK: store ptr null, ptr %2, align 8
+  store ptr null, ptr %2, align 8
+  ret void
+}
+
+declare ptr @malloc(i64)
+declare token @llvm.coro.id(i32, ptr, ptr, ptr)
+declare ptr @llvm.coro.begin(token, ptr)
+declare void @llvm.lifetime.start.p0(i64, ptr)
+declare token @llvm.coro.save(ptr)
+declare void @llvm.lifetime.end.p0(i64, ptr)
+declare void @llvm.coro.await.suspend.void(ptr, ptr, ptr)
+declare i8 @llvm.coro.suspend(token, i1)
+declare i1 @llvm.coro.end(ptr, i1, token)
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nikic wrote:

No need to declare coro intrinsics.

https://github.com/llvm/llvm-project/pull/133918