[clang] [Clang] Make the AS of llvm.compiler.used & llvm.used elements addressspace(0) (PR #164432)

[Juan Manuel Martinez Caamaño via cfe-commits]

https://github.com/jmmartinez updated https://github.com/llvm/llvm-project/pull/164432

>From f7eb56acf40da1accbfa09473ff355f9e232fe08 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Manuel=20Martinez=20Caama=C3=B1o?= <juamarti at amd.com>
Date: Tue, 21 Oct 2025 15:45:36 +0200
Subject: [PATCH 1/2] [Clang] Make the address space of llvm.compiler.used &
 llvm.used 0

---
 clang/lib/CodeGen/CodeGenModule.cpp                  | 12 ++++++------
 .../CodeGen/embed-bitcode-marker-with-nonzero-as.c   |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 1085f45e0fc21..94e3c8bead385 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3281,18 +3281,18 @@ static void emitUsed(CodeGenModule &CGM, StringRef Name,
   if (List.empty())
     return;
 
+  llvm::PointerType *UnqualPtr =
+      llvm::PointerType::getUnqual(CGM.getLLVMContext());
+
   // Convert List to what ConstantArray needs.
   SmallVector<llvm::Constant*, 8> UsedArray;
   UsedArray.resize(List.size());
   for (unsigned i = 0, e = List.size(); i != e; ++i) {
-    UsedArray[i] =
-        llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
-            cast<llvm::Constant>(&*List[i]), CGM.Int8PtrTy);
+    UsedArray[i] = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
+        cast<llvm::Constant>(&*List[i]), UnqualPtr);
   }
 
-  if (UsedArray.empty())
-    return;
-  llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
+  llvm::ArrayType *ATy = llvm::ArrayType::get(UnqualPtr, UsedArray.size());
 
   auto *GV = new llvm::GlobalVariable(
       CGM.getModule(), ATy, false, llvm::GlobalValue::AppendingLinkage,
diff --git a/clang/test/CodeGen/embed-bitcode-marker-with-nonzero-as.c b/clang/test/CodeGen/embed-bitcode-marker-with-nonzero-as.c
index df7118859c764..8af9708a1bfb8 100644
--- a/clang/test/CodeGen/embed-bitcode-marker-with-nonzero-as.c
+++ b/clang/test/CodeGen/embed-bitcode-marker-with-nonzero-as.c
@@ -3,6 +3,6 @@
 
 // CHECK: @llvm.embedded.module = private addrspace(1) constant [0 x i8] zeroinitializer, section ".llvmbc", align 1
 // CHECK-NEXT: @llvm.cmdline = private addrspace(1) constant [{{[0-9]+}} x i8] c"{{.*}}", section ".llvmcmd", align 1
-// CHECK-NEXT: @llvm.compiler.used = appending addrspace(1) global [5 x ptr addrspace(4)] [ptr addrspace(4) addrspacecast (ptr addrspace(1) @foo.managed to ptr addrspace(4)), ptr addrspace(4) addrspacecast (ptr addrspace(1) @foo to ptr addrspace(4)), ptr addrspace(4) addrspacecast (ptr addrspace(1) @__hip_cuid_ to ptr addrspace(4)), ptr addrspace(4) addrspacecast (ptr addrspace(1) @llvm.embedded.module to ptr addrspace(4)), ptr addrspace(4) addrspacecast (ptr addrspace(1) @llvm.cmdline to ptr addrspace(4))], section "llvm.metadata"
+// CHECK-NEXT: @llvm.compiler.used = appending addrspace(1) global [5 x ptr] [ptr addrspacecast (ptr addrspace(1) @foo.managed to ptr), ptr addrspacecast (ptr addrspace(1) @foo to ptr), ptr addrspacecast (ptr addrspace(1) @__hip_cuid_ to ptr), ptr addrspacecast (ptr addrspace(1) @llvm.embedded.module to ptr), ptr addrspacecast (ptr addrspace(1) @llvm.cmdline to ptr)], section "llvm.metadata"
 
 __attribute__((managed)) int foo = 42;

>From 889c8a199ea84efe17f37bd4e406119342a23926 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Manuel=20Martinez=20Caama=C3=B1o?= <juamarti at amd.com>
Date: Wed, 22 Oct 2025 10:01:23 +0200
Subject: [PATCH 2/2] [Review] Add test

---
 .../llvm_compiler_used_elements_are_unqual.c  | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 clang/test/CodeGen/llvm_compiler_used_elements_are_unqual.c

diff --git a/clang/test/CodeGen/llvm_compiler_used_elements_are_unqual.c b/clang/test/CodeGen/llvm_compiler_used_elements_are_unqual.c
new file mode 100644
index 0000000000000..38bc5c893f4bc
--- /dev/null
+++ b/clang/test/CodeGen/llvm_compiler_used_elements_are_unqual.c
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -triple x86_64-- -emit-llvm -x c %s -o - \
+// RUN:   | FileCheck %s --check-prefix=X86
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -emit-llvm -x c %s -o - \
+// RUN:   | FileCheck %s --check-prefix=AMDGCN
+// RUN: %clang_cc1 -triple spirv64-- -emit-llvm -x c %s -o - \
+// RUN:   | FileCheck %s --check-prefix=SPIRV
+// RUN: %clang_cc1 -triple spirv64-amd-amdhsa -emit-llvm -x c %s -o - \
+// RUN:   | FileCheck %s --check-prefix=SPIRV_AMD
+
+static __attribute__((__used__)) int foo = 42;
+
+
+// X86: @foo = internal global i32 42, align 4
+// X86: @llvm.compiler.used = appending global [2 x ptr] [ptr @foo, ptr @bar], section "llvm.metadata"
+//.
+// AMDGCN: @foo = internal addrspace(1) global i32 42, align 4
+// AMDGCN: @llvm.compiler.used = appending addrspace(1) global [2 x ptr] [ptr addrspacecast (ptr addrspace(1) @foo to ptr), ptr @bar], section "llvm.metadata"
+//.
+// SPIRV: @foo = internal global i32 42, align 4
+// SPIRV: @llvm.used = appending addrspace(1) global [2 x ptr] [ptr @foo, ptr @bar], section "llvm.metadata"
+//.
+// SPIRV_AMD: @foo = internal addrspace(1) global i32 42, align 4
+// SPIRV_AMD: @llvm.used = appending addrspace(1) global [2 x ptr] [ptr addrspacecast (ptr addrspace(1) @foo to ptr), ptr addrspacecast (ptr addrspace(4) @bar to ptr)], section "llvm.metadata"
+//.
+// X86-LABEL: define internal void @bar(
+// X86-SAME: ) #[[ATTR0:[0-9]+]] {
+//
+// AMDGCN-LABEL: define internal void @bar(
+// AMDGCN-SAME: ) #[[ATTR0:[0-9]+]] {
+//
+// SPIRV-LABEL: define internal spir_func void @bar(
+// SPIRV-SAME: ) #[[ATTR0:[0-9]+]] {
+//
+// SPIRV_AMD-LABEL: define internal spir_func void @bar(
+// SPIRV_AMD-SAME: ) addrspace(4) #[[ATTR0:[0-9]+]] {
+//
+static void __attribute__((__used__)) bar() {
+}