[NFC][OpenMP][MLIR] Add test for lowering parallel workshare GPU loop (#76144)

This test checks if MLIR code is lowered according to schema presented
below:

func1() {
    call __kmpc_parallel_51(..., func2, ...)
}

func2() {
   call __kmpc_for_static_loop_4u(..., func3, ...)
}

func3() {
   //loop body
}

Author: DominikAdamski

mlir/test/Target/LLVMIR/omptarget-parallel-wsloop.mlir

@@ -0,0 +1,36 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+// The aim of the test is to check the GPU LLVM IR codegen
+// for nested omp do loop inside omp target region
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<#dlti.dl_entry<"dlti.alloca_memory_space", 5 : ui32>>, llvm.data_layout = "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-p7:160:256:256:32-p8:128:128-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5-G1-ni:7:8", llvm.target_triple = "amdgcn-amd-amdhsa", omp.is_gpu = true, omp.is_target_device = true } {
+  llvm.func @target_parallel_wsloop(%arg0: !llvm.ptr ){
+    omp.parallel {
+      %loop_ub = llvm.mlir.constant(9 : i32) : i32
+      %loop_lb = llvm.mlir.constant(0 : i32) : i32
+      %loop_step = llvm.mlir.constant(1 : i32) : i32
+      omp.wsloop for  (%loop_cnt) : i32 = (%loop_lb) to (%loop_ub) inclusive step (%loop_step) {
+        %gep = llvm.getelementptr %arg0[0, %loop_cnt] : (!llvm.ptr, i32) -> !llvm.ptr, !llvm.array<10 x i32>
+        llvm.store %loop_cnt, %gep : i32, !llvm.ptr
+        omp.yield
+      }
+     omp.terminator
+    }
+
+    llvm.return
+  }
+
+}
+// CHECK:      call void @__kmpc_parallel_51(ptr addrspacecast
+// CHECK-SAME:  (ptr addrspace(1) @[[GLOB:[0-9]+]] to ptr),
+// CHECK-SAME:  i32 %[[THREAD_NUM:.*]], i32 1, i32 -1, i32 -1,
+// CHECK-SAME:  ptr @[[PARALLEL_FUNC:.*]], ptr null, ptr %[[PARALLEL_ARGS:.*]], i64 1)
+
+// CHECK:      define internal void @[[PARALLEL_FUNC]]
+// CHECK-SAME:  (ptr noalias noundef %[[TID_ADDR:.*]], ptr noalias noundef %[[ZERO_ADDR:.*]],
+// CHECK-SAME:  ptr %[[ARG_PTR:.*]])
+// CHECK: call void @__kmpc_for_static_loop_4u(ptr addrspacecast (ptr addrspace(1) @[[GLOB]] to ptr),
+// CHECK-SAME:   ptr @[[LOOP_BODY_FUNC:.*]], ptr %[[LOO_BODY_FUNC_ARG:.*]], i32 10,
+// CHECK-SAME:   i32 %[[THREAD_NUM:.*]], i32 0)
+
+// CHECK:      define internal void @[[LOOP_BODY_FUNC]](i32 %[[CNT:.*]], ptr %[[LOOP_BODY_ARG_PTR:.*]]) {