From 4cb4516ae9ae2f267ec755ed0ec6b671fe6747b8 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn@outlook.com>
Date: Wed, 27 Nov 2024 15:55:36 -0600
Subject: [PATCH] [OpenMP] Fix RPC client not being optimized out after changes

Summary:
I forgot that this check deliberately looked through the indirection I
removed. Fix it to just check if the symbol has no users.
---
 llvm/lib/Transforms/IPO/OpenMPOpt.cpp           | 16 +---------------
 llvm/test/Transforms/OpenMP/keep_rpc_client.ll  | 17 +++++------------
 .../test/Transforms/OpenMP/remove_rpc_client.ll |  6 ++----
 3 files changed, 8 insertions(+), 31 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
index 6671fa84c338..b40ab357670b 100644
--- a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
+++ b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
@@ -1539,25 +1539,11 @@ private:
     // safely remove it.
     // TODO: This should be somewhere more common in the future.
     if (GlobalVariable *GV = M.getNamedGlobal("__llvm_rpc_client")) {
-      if (!GV->getType()->isPointerTy())
+      if (GV->getNumUses() >= 1)
         return false;
 
-      Constant *C = GV->getInitializer();
-      if (!C)
-        return false;
-
-      // Check to see if the only user of the RPC client is the external handle.
-      GlobalVariable *Client = dyn_cast<GlobalVariable>(C->stripPointerCasts());
-      if (!Client || Client->getNumUses() > 1 ||
-          Client->user_back() != GV->getInitializer())
-        return false;
-
-      Client->replaceAllUsesWith(PoisonValue::get(Client->getType()));
-      Client->eraseFromParent();
-
       GV->replaceAllUsesWith(PoisonValue::get(GV->getType()));
       GV->eraseFromParent();
-
       return true;
     }
     return false;
diff --git a/llvm/test/Transforms/OpenMP/keep_rpc_client.ll b/llvm/test/Transforms/OpenMP/keep_rpc_client.ll
index d6799e882cbb..b1c40e852a5e 100644
--- a/llvm/test/Transforms/OpenMP/keep_rpc_client.ll
+++ b/llvm/test/Transforms/OpenMP/keep_rpc_client.ll
@@ -2,28 +2,21 @@
 ; RUN: opt -S -passes=openmp-opt-postlink < %s | FileCheck %s --check-prefix=POSTLINK
 ; RUN: opt -S -passes=openmp-opt < %s | FileCheck %s --check-prefix=PRELINK
 
-@client = internal addrspace(1) global i64 zeroinitializer, align 8
-@__llvm_rpc_client = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
+@__llvm_rpc_client = internal addrspace(1) global i64 zeroinitializer, align 8
 
 ;.
-; POSTLINK: @client = internal addrspace(1) global i64 0, align 8
-; POSTLINK: @__llvm_rpc_client = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
-;.
-; PRELINK: @client = internal addrspace(1) global i64 0, align 8
-; PRELINK: @__llvm_rpc_client = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
+; PRELINK: @__llvm_rpc_client = internal addrspace(1) global i64 0, align 8
 ;.
 define i64 @a() {
 ; POSTLINK-LABEL: define {{[^@]+}}@a
 ; POSTLINK-SAME: () #[[ATTR0:[0-9]+]] {
-; POSTLINK-NEXT:    [[RETVAL:%.*]] = load i64, ptr addrspace(1) @client, align 8
-; POSTLINK-NEXT:    ret i64 [[RETVAL]]
+; POSTLINK-NEXT:    ret i64 0
 ;
 ; PRELINK-LABEL: define {{[^@]+}}@a
 ; PRELINK-SAME: () #[[ATTR0:[0-9]+]] {
-; PRELINK-NEXT:    [[RETVAL:%.*]] = load i64, ptr addrspace(1) @client, align 8
-; PRELINK-NEXT:    ret i64 [[RETVAL]]
+; PRELINK-NEXT:    ret i64 0
 ;
-  %retval = load i64, ptr addrspace(1) @client, align 8
+  %retval = load i64, ptr addrspace(1) @__llvm_rpc_client, align 8
   ret i64 %retval
 }
 
diff --git a/llvm/test/Transforms/OpenMP/remove_rpc_client.ll b/llvm/test/Transforms/OpenMP/remove_rpc_client.ll
index 319d2726d996..29f6c6b12e4c 100644
--- a/llvm/test/Transforms/OpenMP/remove_rpc_client.ll
+++ b/llvm/test/Transforms/OpenMP/remove_rpc_client.ll
@@ -2,12 +2,10 @@
 ; RUN: opt -S -passes=openmp-opt-postlink < %s | FileCheck %s --check-prefix=POSTLINK
 ; RUN: opt -S -passes=openmp-opt < %s | FileCheck %s --check-prefix=PRELINK
 
-@client = internal addrspace(1) global i32 zeroinitializer, align 8
-@__llvm_rpc_client = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
+@__llvm_rpc_client = internal addrspace(1) global i32 zeroinitializer, align 8
 
 ;.
-; PRELINK: @client = internal addrspace(1) global i32 0, align 8
-; PRELINK: @__llvm_rpc_client = protected local_unnamed_addr addrspace(1) global ptr addrspacecast (ptr addrspace(1) @client to ptr), align 8
+; PRELINK: @__llvm_rpc_client = internal addrspace(1) global i32 0, align 8
 ;.
 define void @a() {
 ; POSTLINK-LABEL: define {{[^@]+}}@a() {