[llvm] [AMDGPU] Mark cluster_workgroup_id_* intrinsics always uniform (PR #159439)

[Stanislav Mekhanoshin via llvm-commits]

https://github.com/rampitec created https://github.com/llvm/llvm-project/pull/159439

None

>From b357ab508b799d8f6855d81745a914a016545b75 Mon Sep 17 00:00:00 2001
From: Stanislav Mekhanoshin <Stanislav.Mekhanoshin at amd.com>
Date: Wed, 17 Sep 2025 12:47:22 -0700
Subject: [PATCH] [AMDGPU] Mark cluster_workgroup_id_* intrinsics always
 uniform

---
 .../Target/AMDGPU/AMDGPUSearchableTables.td   |  8 +++
 .../AMDGPU/always_uniform.ll                  | 72 +++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSearchableTables.td b/llvm/lib/Target/AMDGPU/AMDGPUSearchableTables.td
index 7be18998ff6b0..2393346839707 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSearchableTables.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSearchableTables.td
@@ -398,6 +398,14 @@ def : AlwaysUniform<int_amdgcn_icmp>;
 def : AlwaysUniform<int_amdgcn_fcmp>;
 def : AlwaysUniform<int_amdgcn_ballot>;
 def : AlwaysUniform<int_amdgcn_if_break>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_id_x>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_id_y>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_id_z>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_flat_id>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_max_id_x>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_max_id_y>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_max_id_z>;
+def : AlwaysUniform<int_amdgcn_cluster_workgroup_max_flat_id>;
 def : AlwaysUniform<int_amdgcn_workgroup_id_x>;
 def : AlwaysUniform<int_amdgcn_workgroup_id_y>;
 def : AlwaysUniform<int_amdgcn_workgroup_id_z>;
diff --git a/llvm/test/Analysis/UniformityAnalysis/AMDGPU/always_uniform.ll b/llvm/test/Analysis/UniformityAnalysis/AMDGPU/always_uniform.ll
index 99d9e28425107..9ff670bee0f89 100644
--- a/llvm/test/Analysis/UniformityAnalysis/AMDGPU/always_uniform.ll
+++ b/llvm/test/Analysis/UniformityAnalysis/AMDGPU/always_uniform.ll
@@ -119,6 +119,70 @@ define void @s_getreg(ptr addrspace(1) inreg %out) {
   ret void
 }
 
+; CHECK-LABEL: for function 'cluster_workgroup_id_x':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_id_x(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.id.x()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_id_y':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_id_y(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.id.y()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_id_z':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_id_z(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.id.z()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_flat_id':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_flat_id(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.flat.id()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_max_id_x':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_max_id_x(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.max.id.x()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_max_id_y':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_max_id_y(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.max.id.y()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_max_id_z':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_max_id_z(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.max.id.z()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: for function 'cluster_workgroup_max_flat_id':
+; CHECK: ALL VALUES UNIFORM
+define void @cluster_workgroup_max_flat_id(ptr addrspace(1) inreg %out) {
+  %result = call i32 @llvm.amdgcn.cluster.workgroup.max.flat.id()
+  store i32 %result, ptr addrspace(1) %out, align 4
+  ret void
+}
+
 ; CHECK-LABEL: for function 's_memtime':
 ; CHECK: ALL VALUES UNIFORM
 define void @s_memtime(ptr addrspace(1) inreg %out) {
@@ -144,6 +208,14 @@ declare i64 @llvm.amdgcn.ballot.i32(i1) #1
 declare i32 @llvm.amdgcn.workgroup.id.x() #0
 declare i32 @llvm.amdgcn.workgroup.id.y() #0
 declare i32 @llvm.amdgcn.workgroup.id.z() #0
+declare i32 @llvm.amdgcn.cluster.workgroup.id.x()
+declare i32 @llvm.amdgcn.cluster.workgroup.id.y()
+declare i32 @llvm.amdgcn.cluster.workgroup.id.z()
+declare i32 @llvm.amdgcn.cluster.workgroup.flat.id()
+declare i32 @llvm.amdgcn.cluster.workgroup.max.id.x()
+declare i32 @llvm.amdgcn.cluster.workgroup.max.id.y()
+declare i32 @llvm.amdgcn.cluster.workgroup.max.id.z()
+declare i32 @llvm.amdgcn.cluster.workgroup.max.flat.id()
 
 attributes #0 = { nounwind readnone }
 attributes #1 = { nounwind readnone convergent }