[MLIR][LLVM] Add memset intrinsic

[wsmoses]

Summary

Add memset intrinsic into LLVM dialect

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

def LLVM_MemcpyOp : LLVM_ZeroResultIntrOp<"memcpy", [0, 1, 2]> {
   let arguments = (ins LLVM_Type:$dst, LLVM_Type:$src, LLVM_Type:$len,
                    LLVM_Type:$isVolatile);
 }
 def LLVM_MemcpyInlineOp : LLVM_ZeroResultIntrOp<"memcpy.inline", [0, 1, 2]> {
   let arguments = (ins LLVM_Type:$dst, LLVM_Type:$src, LLVM_Type:$len,
                    LLVM_Type:$isVolatile);
 }
 
+def LLVM_MemsetOp : LLVM_ZeroResultIntrOp<"memset", [0, 2]> {
+  let arguments = (ins LLVM_Type:$dst, LLVM_Type:$val, LLVM_Type:$len,
+                   LLVM_Type:$isVolatile);
+}
+
 // Intrinsics with multiple returns.
 
 def LLVM_SAddWithOverflowOp
     : LLVM_IntrOp<"sadd.with.overflow", [0], [], [], 2> {
   let arguments = (ins LLVM_Type, LLVM_Type);
 }
 def LLVM_UAddWithOverflowOp
     : LLVM_IntrOp<"uadd.with.overflow", [0], [], [], 2> {

mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir

llvm.func @memcpy_test(%arg0: i32, %arg2: !llvm.ptr<i8>, %arg3: !llvm.ptr<i8>) {
   // CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 %{{.*}}, i1 {{.*}})
   "llvm.intr.memcpy"(%arg2, %arg3, %arg0, %i1) : (!llvm.ptr<i8>, !llvm.ptr<i8>, i32, i1) -> ()
   %sz = llvm.mlir.constant(10: i64) : i64
   // CHECK: call void @llvm.memcpy.inline.p0i8.p0i8.i64(i8* %{{.*}}, i8* %{{.*}}, i64 10, i1 {{.*}})
   "llvm.intr.memcpy.inline"(%arg2, %arg3, %sz, %i1) : (!llvm.ptr<i8>, !llvm.ptr<i8>, i64, i1) -> ()
   llvm.return
 }
 
+// CHECK-LABEL: @memset_test
+llvm.func @memset_test(%arg0: i32, %arg2: !llvm.ptr<i8>, %arg3: i8) {
+  %i1 = llvm.mlir.constant(false) : i1
+  // CHECK: call void @llvm.memset.p0i8.i32(i8* %{{.*}}, i8 %{{.*}}, i32 %{{.*}}, i1 {{.*}})
+  "llvm.intr.memset"(%arg2, %arg3, %arg0, %i1) : (!llvm.ptr<i8>, i8, i32, i1) -> ()
+  llvm.return
+}
+
 // CHECK-LABEL: @sadd_with_overflow_test
 llvm.func @sadd_with_overflow_test(%arg0: i32, %arg1: i32, %arg2: vector<8xi32>, %arg3: vector<8xi32>) {
   // CHECK: call { i32, i1 } @llvm.sadd.with.overflow.i32
   "llvm.intr.sadd.with.overflow"(%arg0, %arg1) : (i32, i32) -> !llvm.struct<(i32, i1)>
   // CHECK: call { <8 x i32>, <8 x i1> } @llvm.sadd.with.overflow.v8i32
   "llvm.intr.sadd.with.overflow"(%arg2, %arg3) : (vector<8xi32>, vector<8xi32>) -> !llvm.struct<(vector<8xi32>, vector<8xi1>)>
   llvm.return
 }