[llvm] Coroutines: Handle non-zero stack address space (PR #67092)

[via llvm-commits]

https://github.com/ruiling created https://github.com/llvm/llvm-project/pull/67092

The stack might be in a different address space, in which case, bitcast does not work. We should use addrspacecast. As we do not support typed pointer anymore, so we do not need a bitcast here anymore.

>From 76b7d87b5a3106fbadc68776ead70f0cd64c0783 Mon Sep 17 00:00:00 2001
From: Ruiling Song <ruiling.song at amd.com>
Date: Mon, 18 Sep 2023 11:20:56 +0800
Subject: [PATCH] Coroutines: Handle non-zero stack address space

The stack might be in a different address space, in which case, bitcast
does not work. We should use addrspacecast. As we do not support typed
pointer anymore, so we do not need a bitcast here anymore.
---
 llvm/lib/Transforms/Coroutines/CoroFrame.cpp  | 13 ++---
 .../Coroutines/coro-alloca-with-addrspace.ll  | 57 +++++++++++++++++++
 2 files changed, 61 insertions(+), 9 deletions(-)
 create mode 100644 llvm/test/Transforms/Coroutines/coro-alloca-with-addrspace.ll

diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index a12dd710174f3f8..cff259f8c59e9fd 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -1758,16 +1758,11 @@ static void insertSpills(const FrameDataInfo &FrameData, coro::Shape &Shape) {
         PtrValue = Builder.CreateAnd(PtrValue, Builder.CreateNot(AlignMask));
         return Builder.CreateIntToPtr(PtrValue, AI->getType());
       }
-      // If the type of GEP is not equal to the type of AllocaInst, it implies
-      // that the AllocaInst may be reused in the Frame slot of other
-      // AllocaInst. So We cast GEP to the AllocaInst here to re-use
-      // the Frame storage.
-      //
-      // Note: If we change the strategy dealing with alignment, we need to refine
-      // this casting.
+      // If the type of GEP is not equal to the type of AllocaInst, it means
+      // that the AllocaInst uses a different address space.
       if (GEP->getType() != Orig->getType())
-        return Builder.CreateBitCast(GEP, Orig->getType(),
-                                     Orig->getName() + Twine(".cast"));
+        return Builder.CreateAddrSpaceCast(GEP, Orig->getType(),
+                                           Orig->getName() + Twine(".cast"));
     }
     return GEP;
   };
diff --git a/llvm/test/Transforms/Coroutines/coro-alloca-with-addrspace.ll b/llvm/test/Transforms/Coroutines/coro-alloca-with-addrspace.ll
new file mode 100644
index 000000000000000..410d3e35e1c930b
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-alloca-with-addrspace.ll
@@ -0,0 +1,57 @@
+; RUN: opt < %s -passes='cgscc(coro-split)' -S | FileCheck %s
+
+define ptr @f(i1 %n) presplitcoroutine {
+entry:
+  %x = alloca i64, addrspace(5)
+  %y = alloca i64, addrspace(5)
+  %id = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
+  %size = call i32 @llvm.coro.size.i32()
+  %alloc = call ptr @malloc(i32 %size)
+  %hdl = call ptr @llvm.coro.begin(token %id, ptr %alloc)
+  br i1 %n, label %flag_true, label %flag_false
+
+flag_true:
+  br label %merge
+
+flag_false:
+  br label %merge
+
+merge:
+  %alias_phi = phi ptr addrspace(5) [ %x, %flag_true ], [ %y, %flag_false ]
+  %sp1 = call i8 @llvm.coro.suspend(token none, i1 false)
+  switch i8 %sp1, label %suspend [i8 0, label %resume
+                                  i8 1, label %cleanup]
+resume:
+  call void @print(ptr addrspace(5) %alias_phi)
+  br label %cleanup
+
+cleanup:
+  %mem = call ptr @llvm.coro.free(token %id, ptr %hdl)
+  call void @free(ptr %mem)
+  br label %suspend
+
+suspend:
+  call i1 @llvm.coro.end(ptr %hdl, i1 0)
+  ret ptr %hdl
+}
+
+; CHECK-LABEL: @f(
+; CHECK:  [[X_ADDR:%[0-9]+]] = getelementptr inbounds %f.Frame, ptr %hdl, i32 0, i32 2
+; CHECK:  %x.reload.addr = addrspacecast ptr [[X_ADDR]] to ptr addrspace(5)
+; CHECK:  [[Y_ADDR:%[0-9]+]] = getelementptr inbounds %f.Frame, ptr %hdl, i32 0, i32 3
+; CHECK:  %y.reload.addr = addrspacecast ptr [[Y_ADDR]] to ptr addrspace(5)
+
+declare ptr @llvm.coro.free(token, ptr)
+declare i32 @llvm.coro.size.i32()
+declare i8  @llvm.coro.suspend(token, i1)
+declare void @llvm.coro.resume(ptr)
+declare void @llvm.coro.destroy(ptr)
+
+declare token @llvm.coro.id(i32, ptr, ptr, ptr)
+declare i1 @llvm.coro.alloc(token)
+declare ptr @llvm.coro.begin(token, ptr)
+declare i1 @llvm.coro.end(ptr, i1)
+
+declare void @print(ptr)
+declare noalias ptr @malloc(i32)
+declare void @free(ptr)