[AMDGPU] Fix module LDS selection

[rampitec]

Summary

Accesses to global module LDS variable start from null,
but kernel also thinks its variables start address is
null. Fixed by not using a null as an address.

[arsenm]

llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp

67

getNamedGlobal?

[JonChesterfield]

That is much prettier, thank you.

We have the magic string "llvm.amdgcn.module.lds" in a few places now, might be worth putting that behind a function call. Separate to the above, if we do it at all.

[rampitec]

llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp

67

Probably. But that's a different change I guess.

[arsenm]

llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp

67

No, that's the wrapper that passes true in for you

[rampitec]

In D102882#2772399, @JonChesterfield wrote:

That is much prettier, thank you.

We have the magic string "llvm.amdgcn.module.lds" in a few places now, might be worth putting that behind a function call. Separate to the above, if we do it at all.

Yeah, I think we need a function to return it or define.

llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp

67

Ah, right.

llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp

SDValue AMDGPUTargetLowering::LowerGlobalAddress(AMDGPUMachineFunction* MFI,
                                                  SelectionDAG &DAG) const {
 
   const DataLayout &DL = DAG.getDataLayout();
   GlobalAddressSDNode *G = cast<GlobalAddressSDNode>(Op);
   const GlobalValue *GV = G->getGlobal();
 
   if (G->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS ||
       G->getAddressSpace() == AMDGPUAS::REGION_ADDRESS) {
-    if (!MFI->isModuleEntryFunction()) {
+    if (!MFI->isModuleEntryFunction() &&
+        !GV->getName().equals("llvm.amdgcn.module.lds")) {
       SDLoc DL(Op);
       const Function &Fn = DAG.getMachineFunction().getFunction();
       DiagnosticInfoUnsupported BadLDSDecl(
         Fn, "local memory global used by non-kernel function",
         DL.getDebugLoc(), DS_Warning);
       DAG.getContext()->diagnose(BadLDSDecl);
 
       // We currently don't have a way to correctly allocate LDS objects that

llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp

bool AMDGPULegalizerInfo::legalizeGlobalValue(
   LLT Ty = MRI.getType(DstReg);
   unsigned AS = Ty.getAddressSpace();
 
   const GlobalValue *GV = MI.getOperand(1).getGlobal();
   MachineFunction &MF = B.getMF();
   SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
 
   if (AS == AMDGPUAS::LOCAL_ADDRESS || AS == AMDGPUAS::REGION_ADDRESS) {
-    if (!MFI->isModuleEntryFunction()) {
+    if (!MFI->isModuleEntryFunction() &&
+        !GV->getName().equals("llvm.amdgcn.module.lds")) {
       const Function &Fn = MF.getFunction();
       DiagnosticInfoUnsupported BadLDSDecl(
         Fn, "local memory global used by non-kernel function", MI.getDebugLoc(),
         DS_Warning);
       Fn.getContext().diagnose(BadLDSDecl);
 
       // We currently don't have a way to correctly allocate LDS objects that
       // aren't directly associated with a kernel. We do force inlining of

llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp

std::transform(
         LocalVars.cbegin(), LocalVars.cend(), std::back_inserter(LocalVarTypes),
         [](const GlobalVariable *V) -> Type * { return V->getValueType(); });
 
     StructType *LDSTy = StructType::create(
         Ctx, LocalVarTypes, llvm::StringRef("llvm.amdgcn.module.lds.t"));
 
     Align MaxAlign =
         AMDGPU::getAlign(DL, LocalVars[0]); // was sorted on alignment
-    Constant *InstanceAddress = Constant::getIntegerValue(
-        PointerType::get(LDSTy, AMDGPUAS::LOCAL_ADDRESS), APInt(32, 0));
 
     GlobalVariable *SGV = new GlobalVariable(
         M, LDSTy, false, GlobalValue::InternalLinkage, UndefValue::get(LDSTy),
         "llvm.amdgcn.module.lds", nullptr, GlobalValue::NotThreadLocal,
         AMDGPUAS::LOCAL_ADDRESS, false);
     SGV->setAlignment(MaxAlign);
     appendToCompilerUsed(
         M, {static_cast<GlobalValue *>(
                ConstantExpr::getPointerBitCastOrAddrSpaceCast(
                    cast<Constant>(SGV), Type::getInt8PtrTy(Ctx)))});
 
     // The verifier rejects used lists containing an inttoptr of a constant
     // so remove the variables from these lists before replaceAllUsesWith
     removeFromUsedLists(M, LocalVars);
 
     // Replace uses of ith variable with a constantexpr to the ith field of the
     // instance that will be allocated by AMDGPUMachineFunction
     Type *I32 = Type::getInt32Ty(Ctx);
     for (size_t I = 0; I < LocalVars.size(); I++) {
       GlobalVariable *GV = LocalVars[I];
       Constant *GEPIdx[] = {ConstantInt::get(I32, 0), ConstantInt::get(I32, I)};
       GV->replaceAllUsesWith(
-          ConstantExpr::getGetElementPtr(LDSTy, InstanceAddress, GEPIdx));
+          ConstantExpr::getGetElementPtr(LDSTy, SGV, GEPIdx));
       GV->eraseFromParent();
     }
 
     // Mark kernels with asm that reads the address of the allocated structure
     // This is not necessary for lowering. This lets other passes, specifically
     // PromoteAlloca, accurately calculate how much LDS will be used by the
     // kernel after lowering.
     {

llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp

unsigned AMDGPUMachineFunction::allocateLDSGlobal(const DataLayout &DL,
   // memory.
   LDSSize = alignTo(StaticLDSSize, DynLDSAlign);
 
   return Offset;
 }
 
 void AMDGPUMachineFunction::allocateModuleLDSGlobal(const Module *M) {
   if (isModuleEntryFunction()) {
-    GlobalVariable *GV = M->getGlobalVariable("llvm.amdgcn.module.lds");
+    const GlobalVariable *GV = M->getNamedGlobal("llvm.amdgcn.module.lds");
     if (GV) {
       unsigned Offset = allocateLDSGlobal(M->getDataLayout(), *GV);
       (void)Offset;
       assert(Offset == 0 &&
              "Module LDS expected to be allocated before other LDS");
     }
   }
 }

llvm/test/CodeGen/AMDGPU/lower-module-lds-constantexpr.ll

 ; @both is used from a non-kernel function so is rewritten
 ; CHECK-NOT: @both
 ; sorted both < func, so @both at null and @func at 4
 @both = addrspace(3) global float undef, align 4
 
 ; CHECK: @llvm.amdgcn.module.lds = internal addrspace(3) global %llvm.amdgcn.module.lds.t undef, align 4
 
 ; CHECK-LABEL: @get_func()
-; CHECK: %0 = load i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* getelementptr (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* null, i32 0, i32 1) to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* getelementptr (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* null, i32 0, i32 1) to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
+; CHECK: %0 = load i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 1) to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 1) to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
 define i32 @get_func() local_unnamed_addr #0 {
 entry:
   %0 = load i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @func to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @func to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
   ret i32 %0
 }
 
 ; CHECK-LABEL: @set_func(i32 %x)
-; CHECK: store i32 %x, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* null to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* null to i32*) to i64)) to i32*), align 4
+; CHECK:  store i32 %x, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
 define void @set_func(i32 %x) local_unnamed_addr #1 {
 entry:
   store i32 %x, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @both to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @both to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
   ret void
 }
 
 ; CHECK-LABEL: @timestwo()
 ; CHECK: call void @llvm.donothing() [ "ExplicitUse"(%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds) ]
-; CHECK: %ld = load i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* null to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @kern to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
+; CHECK: %ld = load i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @kern to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
 ; CHECK: %mul = mul i32 %ld, 2
-; CHECK: store i32 %mul, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @kern to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* null to i32*) to i64)) to i32*), align 4
+; CHECK: store i32 %mul, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @kern to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
 define amdgpu_kernel void @timestwo() {
   %ld = load i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @both to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @kern to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
   %mul = mul i32 %ld, 2
   store i32 %mul, i32* inttoptr (i64 add (i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @kern to i32 addrspace(3)*) to i32*) to i64), i64 ptrtoint (i32* addrspacecast (i32 addrspace(3)* bitcast (float addrspace(3)* @both to i32 addrspace(3)*) to i32*) to i64)) to i32*), align 4
   ret void
 }

llvm/test/CodeGen/AMDGPU/lower-module-lds-indirect.ll

 ; RUN: opt -S -mtriple=amdgcn-- -amdgpu-lower-module-lds < %s | FileCheck %s
 ; RUN: opt -S -mtriple=amdgcn-- -passes=amdgpu-lower-module-lds < %s | FileCheck %s
 
 ; CHECK: %llvm.amdgcn.module.lds.t = type { double, float }
 
-; CHECK: @function_indirect = addrspace(1) global float* addrspacecast (float addrspace(3)* getelementptr (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* null, i32 0, i32 1) to float*), align 8
+; CHECK: @function_indirect = addrspace(1) global float* addrspacecast (float addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 1) to float*), align 8
 
-; CHECK: @kernel_indirect = addrspace(1) global double* addrspacecast (double addrspace(3)* null to double*), align 8
+; CHECK: @kernel_indirect = addrspace(1) global double* addrspacecast (double addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 0) to double*), align 8
 
 ; CHECK: @llvm.amdgcn.module.lds = internal addrspace(3) global %llvm.amdgcn.module.lds.t undef, align 8
 
 @function_target = addrspace(3) global float undef, align 4
 @function_indirect = addrspace(1) global float* addrspacecast (float addrspace(3)* @function_target to float*), align 8
 
 @kernel_target = addrspace(3) global double undef, align 8
 @kernel_indirect = addrspace(1) global double* addrspacecast (double addrspace(3)* @kernel_target to double*), align 8

llvm/test/CodeGen/AMDGPU/lower-module-lds-offsets.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -mtriple=amdgcn-- -amdgpu-lower-module-lds < %s | FileCheck -check-prefix=OPT %s
+; RUN: opt -S -mtriple=amdgcn-- -passes=amdgpu-lower-module-lds < %s | FileCheck -check-prefix=OPT %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
+
+; Check that module LDS is allocated at address 0 and kernel starts its
+; allocation past module LDS.
+
[e-mail].1 = internal unnamed_addr addrspace(3) global [1 x i8] undef, align 1
[e-mail].16 = internal unnamed_addr addrspace(3) global [16 x i8] undef, align 16
+
+; GCN-LABEL: {{^}}k0:
+; GCN-DAG: v_mov_b32_e32 [[NULL:v[0-9]+]], 0
+; GCN-DAG: v_mov_b32_e32 [[ONE:v[0-9]+]], 1
+; GCN:     ds_write_b8 [[NULL]], [[ONE]]
+; GCN:     v_mov_b32_e32 [[TWO:v[0-9]+]], 2
+; GCN:     ds_write_b8 [[NULL]], [[TWO]] offset:16
+define amdgpu_kernel void @k0() {
+; OPT-LABEL: @k0(
+; OPT-NEXT:    call void @llvm.donothing() [ "ExplicitUse"([[LLVM_AMDGCN_MODULE_LDS_T:%.*]] addrspace(3)* @llvm.amdgcn.module.lds) ]
+; OPT-NEXT:    [[LDS_SIZE_1_ALIGN_1_BC:%.*]] = bitcast [1 x i8] addrspace(3)* getelementptr inbounds ([[LLVM_AMDGCN_MODULE_LDS_T]], [[LLVM_AMDGCN_MODULE_LDS_T]] addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 0) to i8 addrspace(3)*
+; OPT-NEXT:    store i8 1, i8 addrspace(3)* [[LDS_SIZE_1_ALIGN_1_BC]], align 1
+; OPT-NEXT:    [[LDS_SIZE_16_ALIGN_16_BC:%.*]] = bitcast [16 x i8] addrspace(3)* @lds.size.16.align.16 to i8 addrspace(3)*
+; OPT-NEXT:    store i8 2, i8 addrspace(3)* [[LDS_SIZE_16_ALIGN_16_BC]], align 16
+; OPT-NEXT:    ret void
+;
+  %lds.size.1.align.1.bc = bitcast [1 x i8] addrspace(3)* @lds.size.1.align.1 to i8 addrspace(3)*
+  store i8 1, i8 addrspace(3)* %lds.size.1.align.1.bc, align 1
+  %lds.size.16.align.16.bc = bitcast [16 x i8] addrspace(3)* @lds.size.16.align.16 to i8 addrspace(3)*
+  store i8 2, i8 addrspace(3)* %lds.size.16.align.16.bc, align 16
+  ret void
+}
+
+; GCN-LABEL: {{^}}f0:
+; GCN-DAG: v_mov_b32_e32 [[NULL:v[0-9]+]], 0
+; GCN-DAG: v_mov_b32_e32 [[TREE:v[0-9]+]], 3
+; GCN:     ds_write_b8 [[NULL]], [[TREE]]
+define void @f0() {
+; OPT-LABEL: @f0(
+; OPT-NEXT:    [[LDS_SIZE_1_ALIGN_1_BC:%.*]] = bitcast [1 x i8] addrspace(3)* getelementptr inbounds ([[LLVM_AMDGCN_MODULE_LDS_T:%.*]], [[LLVM_AMDGCN_MODULE_LDS_T]] addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 0) to i8 addrspace(3)*
+; OPT-NEXT:    store i8 3, i8 addrspace(3)* [[LDS_SIZE_1_ALIGN_1_BC]], align 1
+; OPT-NEXT:    ret void
+;
+  %lds.size.1.align.1.bc = bitcast [1 x i8] addrspace(3)* @lds.size.1.align.1 to i8 addrspace(3)*
+  store i8 3, i8 addrspace(3)* %lds.size.1.align.1.bc, align 1
+  ret void
+}

llvm/test/CodeGen/AMDGPU/lower-module-lds-used-list.ll

 @llvm.used = appending global [2 x i8*] [i8* addrspacecast (i8 addrspace(3)* bitcast (float addrspace(3)* @tolower to i8 addrspace(3)*) to i8*), i8* addrspacecast (i8 addrspace(1)* bitcast (i64 addrspace(1)* @ignored to i8 addrspace(1)*) to i8*)], section "llvm.metadata"
 
 ; @ignored still in list, @tolower removed, llvm.amdgcn.module.lds appended
 ; CHECK: @llvm.compiler.used = appending global [2 x i8*] [i8* addrspacecast (i8 addrspace(1)* bitcast (i64 addrspace(1)* @ignored to i8 addrspace(1)*) to i8*), i8* addrspacecast (i8 addrspace(3)* bitcast (%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds to i8 addrspace(3)*) to i8*)], section "llvm.metadata"
 
 @llvm.compiler.used = appending global [2 x i8*] [i8* addrspacecast (i8 addrspace(3)* bitcast (float addrspace(3)* @tolower to i8 addrspace(3)*) to i8*), i8* addrspacecast (i8 addrspace(1)* bitcast (i64 addrspace(1)* @ignored to i8 addrspace(1)*) to i8*)], section "llvm.metadata"
 
 ; CHECK-LABEL: @func()
-; CHECK: %dec = atomicrmw fsub float addrspace(3)* null, float 1.0
+; CHECK: %dec = atomicrmw fsub float addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 0), float 1.000000e+00 monotonic, align 4
 define void @func() {
   %dec = atomicrmw fsub float addrspace(3)* @tolower, float 1.0 monotonic
   %unused0 = atomicrmw add i64 addrspace(1)* @ignored, i64 1 monotonic
   ret void
 }

llvm/test/CodeGen/AMDGPU/lower-module-lds.ll

 
 ; A variable that is unchanged by pass
 ; CHECK: @with_init = addrspace(3) global i64 0
 @with_init = addrspace(3) global i64 0
 
 ; Instance of new type, aligned to max of element alignment
 ; CHECK: @llvm.amdgcn.module.lds = internal addrspace(3) global %llvm.amdgcn.module.lds.t undef, align 8
 
-; Use in func rewritten to access struct at address zero, which prints as null
+; Use in func rewritten to access struct at address zero
 ; CHECK-LABEL: @func()
-; CHECK: %dec = atomicrmw fsub float addrspace(3)* null, float 1.0
-; CHECK: %val0 = load i32, i32 addrspace(3)* getelementptr (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* null, i32 0, i32 2), align 4
+; CHECK: %dec = atomicrmw fsub float addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 0), float 1.0
+; CHECK: %val0 = load i32, i32 addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 2), align 4
 ; CHECK: %val1 = add i32 %val0, 4
-; CHECK: store i32 %val1, i32 addrspace(3)* getelementptr (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* null, i32 0, i32 2), align 4
+; CHECK: store i32 %val1, i32 addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 2), align 4
 ; CHECK: %unused0 = atomicrmw add i64 addrspace(3)* @with_init, i64 1 monotonic
 define void @func() {
   %dec = atomicrmw fsub float addrspace(3)* @var0, float 1.0 monotonic
   %val0 = load i32, i32 addrspace(3)* @var1, align 4
   %val1 = add i32 %val0, 4
   store i32 %val1, i32 addrspace(3)* @var1, align 4
   %unused0 = atomicrmw add i64 addrspace(3)* @with_init, i64 1 monotonic
   ret void
 }
 
 ; This kernel calls a function that uses LDS so needs the block
 ; CHECK-LABEL: @kern_call()
 ; CHECK: call void @llvm.donothing() [ "ExplicitUse"(%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds) ]
 ; CHECK: call void @func()
-; CHECK: %dec = atomicrmw fsub float addrspace(3)* null, float 2.0
+; CHECK: %dec = atomicrmw fsub float addrspace(3)* getelementptr inbounds (%llvm.amdgcn.module.lds.t, %llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds, i32 0, i32 0), float 2.000000e+00 monotonic, align 4
 define amdgpu_kernel void @kern_call() {
   call void @func()
   %dec = atomicrmw fsub float addrspace(3)* @var0, float 2.0 monotonic
   ret void
 }
 
 ; This kernel does not need to alloc the LDS block as it makes no calls
 ; CHECK-LABEL: @kern_empty()
 ; CHECK: call void @llvm.donothing() [ "ExplicitUse"(%llvm.amdgcn.module.lds.t addrspace(3)* @llvm.amdgcn.module.lds) ]
 define spir_kernel void @kern_empty() {
   ret void
 }