[mlir][nvvm] Add clock and clock64 special registers (#77088)

Tihs PR adds `clock` and `clock64` special registers to NVVM dialect.

Author: grypp

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

@@ -156,6 +156,11 @@ def NVVM_GridInClusterDimZOp : NVVM_SpecialRegisterOp<"read.ptx.sreg.cluster.nct
 def NVVM_ClusterId : NVVM_SpecialRegisterOp<"read.ptx.sreg.cluster.ctarank">;
 def NVVM_ClusterDim : NVVM_SpecialRegisterOp<"read.ptx.sreg.cluster.nctarank">;
 
+//===----------------------------------------------------------------------===//
+// Clock registers
+def NVVM_ClockOp : NVVM_SpecialRegisterOp<"read.ptx.sreg.clock">;
+def NVVM_Clock64Op : NVVM_SpecialRegisterOp<"read.ptx.sreg.clock64">;
+
 //===----------------------------------------------------------------------===//
 // NVVM approximate op definitions
 //===----------------------------------------------------------------------===//

mlir/test/Target/LLVMIR/nvvmir.mlir

@@ -58,6 +58,10 @@ llvm.func @nvvm_special_regs() -> i32 {
   %27 = nvvm.read.ptx.sreg.cluster.ctarank : i32
   // CHECK: call i32 @llvm.nvvm.read.ptx.sreg.cluster.nctarank
   %28 = nvvm.read.ptx.sreg.cluster.nctarank : i32
+  // CHECK: call i32 @llvm.nvvm.read.ptx.sreg.clock
+  %29 = nvvm.read.ptx.sreg.clock : i32
+  // CHECK: call i64 @llvm.nvvm.read.ptx.sreg.clock64
+  %30 = nvvm.read.ptx.sreg.clock64 : i64
 
   llvm.return %1 : i32
 }