[MLIR][NVVM] Add nanosleep

Author: grypp

mlir/include/mlir/Dialect/LLVMIR/NVVMOps.td

@@ -401,6 +401,36 @@ def NVVM_ReduxOp :
    }];   
 }
 
+//===----------------------------------------------------------------------===//
+// NVVM nanosleep
+//===----------------------------------------------------------------------===//
+
+def NVVM_NanosleepOp : NVVM_Op<"nanosleep">,
+  Arguments<(ins 
+  ConfinedAttr<I32Attr, [IntMinValue<1>, IntMaxValue<1000000>]>:$duration)> 
+{
+  let summary = "Suspends the thread for a sleep.";
+
+  let description = [{
+    The Op suspends the thread for a sleep duration approximately close to the 
+    delay `$duration`, specified in nanoseconds. 
+
+    The sleep duration is approximated, but guaranteed to be in the 
+    interval [0, 2*t]. The maximum sleep duration is 1 millisecond. 
+    The implementation may reduce the sleep duration for individual threads 
+    within a warp such that all sleeping threads in the warp wake up together.
+
+    [For more information, see PTX ISA](https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#miscellaneous-instructions-nanosleep)
+  }];
+  
+  string llvmBuilder = [{
+      createIntrinsicCall(builder, 
+                          llvm::Intrinsic::nvvm_nanosleep, 
+                          {builder.getInt32($duration)});
+  }];
+  let assemblyFormat = "attr-dict $duration";
+}
+
 //===----------------------------------------------------------------------===//
 // NVVM Performance Monitor events
 //===----------------------------------------------------------------------===//

mlir/test/Target/LLVMIR/nvvmir-invalid.mlir

@@ -495,3 +495,11 @@ llvm.func @ld_matrix(%arg0: !llvm.ptr<3>) {
   %l = nvvm.ldmatrix %arg0 {num = 1 : i32, layout = #nvvm.mma_layout<col>, shape = #nvvm.ld_st_matrix_shape<m = 16, n = 16>, eltType  = #nvvm.ld_st_matrix_elt_type<b8>} : (!llvm.ptr<3>) -> i32
   llvm.return
 }
+
+// -----
+
+llvm.func @nanosleep() {
+  // expected-error@+1 {{integer constant out of range for attribute}}
+  nvvm.nanosleep 100000000000000
+  llvm.return
+}

mlir/test/Target/LLVMIR/nvvmir.mlir

@@ -959,3 +959,12 @@ llvm.func @nvvm_pmevent() {
   nvvm.pmevent mask = 4
   llvm.return
 }
+
+// -----
+
+// CHECK-LABEL: @nanosleep
+llvm.func @nanosleep() {
+  // CHECK: call void @llvm.nvvm.nanosleep(i32 4000)
+  nvvm.nanosleep 4000
+  llvm.return
+}