Revert "[Clang] Make the AS of llvm.compiler.used & llvm.used elements addrspace(0)" (#166242)

Reverts #164432

Breaks Comgr tests with the following:


[2025-11-03T19:18:20.564Z] + clang -x hip --offload-arch=amdgcnspirv
-nogpulib -nogpuinc --no-gpu-bundle-output --offload-device-only -O3
/jenkins/workspace/compiler-psdb-amd-staging/repos/llvm-project/amd/comgr/test-lit/spirv-tests/spirv-to-reloc.hip
-o
/jenkins/workspace/compiler-psdb-amd-staging/repos/out/ubuntu-22.04/22.04/build/amd_comgr/test-lit/spirv-tests/Output/spirv-to-reloc.hip.tmp.spv
-fvisibility=hidden -fno-autolink -fexceptions -fcolor-diagnostics

[2025-11-03T19:18:20.564Z] InvalidModule: Invalid SPIR-V module: Casts
from private/local/global address space are allowed only to generic

[2025-11-03T19:18:20.564Z] 

[2025-11-03T19:18:20.564Z] <badref> = addrspacecast ptr addrspace(1)
@__hip_cuid_94fb83be5559070 to ptr

[2025-11-03T19:18:20.564Z] clang: error: amdgcn-link command failed with
exit code 10 (use -v to see invocation)

Author: lamb-j

clang/lib/CodeGen/CodeGenModule.cpp

@@ -3331,18 +3331,18 @@ 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]), UnqualPtr);
+    UsedArray[i] =
+        llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
+            cast<llvm::Constant>(&*List[i]), CGM.Int8PtrTy);
   }
 
-  llvm::ArrayType *ATy = llvm::ArrayType::get(UnqualPtr, UsedArray.size());
+  if (UsedArray.empty())
+    return;
+  llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
 
   auto *GV = new llvm::GlobalVariable(
       CGM.getModule(), ATy, false, llvm::GlobalValue::AppendingLinkage,

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] [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"
+// 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"
 
 __attribute__((managed)) int foo = 42;