[XLA:GPU][Emitters] Make xla_gpu.shuffle_reduce syntax similar to xla_gpu.reduce.

xla/service/gpu/fusions/ir/tests/ops.mlir

@@ -261,3 +261,21 @@ func.func @reindex_pad(%in0: tensor<1022xf32>) -> tensor<16x64xf32> {
 // CHECK:         %[[C0:.*]] = arith.constant 0.00
 // CHECK:         xla_gpu.reindex %[[IN1]] at #[[$MAP]] default %[[C0]] :
 // CHECK-SAME:      tensor<1022xf32> -> tensor<16x64xf32>
+
+
+// -----
+
+func.func @do_nothing(%a: f32, %b: i32, %c: f32, %d: i32) -> (f32, i32) {
+  return %a, %b : f32, i32
+}
+func.func @shuffler(%a: f32, %b: i32) -> (f32, i32) {
+  %ret:2 = xla_gpu.shuffle_reduce(%a, %b) to 4 combiner=@do_nothing
+    {xla.range = [0 : index, 42 : index]} : f32, i32
+  return %ret#0, %ret#1 : f32, i32
+}
+// CHECK-LABEL: func.func @shuffler(
+// CHECK-SAME:    %[[IN1:.*]]: f32, %[[IN2:.*]]: i32)
+
+// CHECK:        xla_gpu.shuffle_reduce(%[[IN1]], %[[IN2]]) to 4
+// CHECK-SAME:    combiner=@do_nothing {xla.range = [0 : index, 42 : index]}
+// CHECK-SAME:    : f32, i32

xla/service/gpu/fusions/ir/xla_gpu_ops.cc

@@ -1190,6 +1190,45 @@ LogicalResult ReduceOp::verify() {
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// ShuffleReduceOp
+//===----------------------------------------------------------------------===//
+
+ParseResult ShuffleReduceOp::parse(OpAsmParser& parser,
+                                   OperationState& result) {
+  SmallVector<OpAsmParser::UnresolvedOperand, 4> inputs;
+  mlir::StringAttr combiner;
+  int64_t max_distance;
+  SmallVector<Type, 2> operand_types;
+  mlir::SMLoc loc = parser.getCurrentLocation();
+  if (parser.parseLParen() || parseOperands(parser, &inputs) ||
+      parser.parseRParen() || parser.parseKeyword("to") ||
+      parser.parseInteger(max_distance) || parser.parseKeyword("combiner") ||
+      parser.parseEqual() || parser.parseSymbolName(combiner) ||
+      parser.parseOptionalAttrDict(result.attributes) ||
+      parser.parseColonTypeList(operand_types) ||
+      parser.resolveOperands(inputs, operand_types, loc, result.operands)) {
+    return failure();
+  }
+  auto ctx = result.getContext();
+  mlir::OperationName opname(ShuffleReduceOp::getOperationName(), ctx);
+  result.addAttribute(ShuffleReduceOp::getCombinerAttrName(opname),
+                      mlir::FlatSymbolRefAttr::get(ctx, combiner));
+  result.addAttribute(
+      ShuffleReduceOp::getMaxDistanceAttrName(opname),
+      mlir::IntegerAttr::get(mlir::IntegerType::get(ctx, 64), max_distance));
+  result.addTypes(operand_types);
+  return success();
+}
+
+void ShuffleReduceOp::print(OpAsmPrinter& p) {
+  p << '(' << getOperands() << ") to " << getMaxDistance() << " combiner=@"
+    << getCombiner();
+  p.printOptionalAttrDict((*this)->getAttrs(),
+                          {getCombinerAttrName(), getMaxDistanceAttrName()});
+  p << " : " << TypeRange(getResultTypes());
+}
+
 }  // namespace gpu
 }  // namespace xla
 

xla/service/gpu/fusions/ir/xla_gpu_ops.td

@@ -169,39 +169,35 @@ def XLAGPU_ShuffleReduceOp : XLAGPU_Op<"shuffle_reduce",
     function. The function is invoked with the operands from the low lanes,
     followed by the operands from the high lanes. For example:
 
-   // TODO: update the syntax to make it similar to xla_gpu.reduce.
     ```
-    shuffle_reduce @argmax(%value, %idx) : (f32, index)
+    %result:2 = xla_gpu.shuffle_reduce (%in0, %in1) to 16 combiner=@argmax
     ```
 
     Will perform shuffles with distance 16, 8, 4, 2 and 1, and will invoke
     @argmax five times. The first invocations will be
 
     ```
-    @argmax(%value[i], %idx[i], %value[16+i], %idx[16+i])
+    @argmax(%in0[i], %in1[i], %in0[16+i], %in1[16+i])
     ```
   }];
   let builders = [
-    OpBuilder<(ins "mlir::func::FuncOp":$reducer, "mlir::ValueRange":$operands, "int64_t":$max_distance), [{
+    OpBuilder<(ins "mlir::func::FuncOp":$combiner, "mlir::ValueRange":$operands, "int64_t":$max_distance), [{
       $_state.addOperands(operands);
-      $_state.addAttribute("reducer", mlir::SymbolRefAttr::get(reducer));
+      $_state.addAttribute("combiner", mlir::SymbolRefAttr::get(combiner));
       $_state.addAttribute("max_distance",
           mlir::IntegerAttr::get(
-              mlir::IntegerType::get(reducer.getContext(), 64),
+              mlir::IntegerType::get(combiner.getContext(), 64),
               max_distance));
-      $_state.addTypes(reducer.getFunctionType().getResults());
+      $_state.addTypes(combiner.getFunctionType().getResults());
     }]>];
-  let arguments = (ins FlatSymbolRefAttr:$reducer,
+  let arguments = (ins FlatSymbolRefAttr:$combiner,
                    Variadic<AnyType>:$operands,
                    I64Attr:$max_distance);
   let results = (outs Variadic<AnyType>:$results);
 
-  let assemblyFormat = [{
-    $reducer `(` $operands `)` `to` $max_distance attr-dict `:` type($operands)
-  }];
   let extraClassDeclaration = [{
     mlir::CallInterfaceCallable getCallableForCallee() {
-      return (*this)->getAttrOfType<mlir::SymbolRefAttr>("reducer");
+      return (*this)->getAttrOfType<mlir::SymbolRefAttr>("combiner");
     }
     operand_range getArgOperands() {
       return getOperands();
@@ -213,6 +209,7 @@ def XLAGPU_ShuffleReduceOp : XLAGPU_Op<"shuffle_reduce",
       (*this)->setAttr("reducer", callee.get<mlir::SymbolRefAttr>());
     }
   }];
+  let hasCustomAssemblyFormat = 1;
 }
 
 def XLAGPU_PredicatedInsertOp : XLAGPU_Op<"predicated_insert",
@@ -431,7 +428,7 @@ def XLAGPU_ReduceOp : XLAGPU_Op<"reduce", [
       func.return %0, %1 : f32, i32
     }
     %sum:2 = xla_gpu.reduce (%in0, %in1) inits(%init0, %init1) dimensions=[0, 2]
-      combiner=@add
+      combiner=@add : tensor<16x8x4xf32>, tensor<16x8x4xi32>
     ```
   }];
   let arguments = (ins

xla/service/gpu/fusions/tests/reduce_column_small/f32_2.hlo

@@ -20,4 +20,4 @@ fusion {
 // CHECK: gpu.thread_id x {xla.range = [0 : index, 63 : index]}
 // CHECK-NOT: vector<
 // CHECK: allocate_shared : tensor<32x3xf32>
-// CHECK: shuffle_reduce @add_add{{.*}} to 16 : f32
+// CHECK: shuffle_reduce(%{{.*}}) to 16 combiner=@add_add

xla/service/gpu/fusions/tests/reduce_column_small/f32_32_v2.hlo

@@ -14,4 +14,4 @@ fusion {
 
 // CHECK: vector<2xf32>
 // CHECK: allocate_shared : tensor<8x33xf32>
-// CHECK: shuffle_reduce @add_add{{.*}} to 4 : f32
+// CHECK: shuffle_reduce(%{{.*}}) to 4 combiner=@add_add

xla/service/gpu/fusions/tests/reduce_column_small/f32_8_v2.hlo

@@ -13,4 +13,4 @@ fusion {
 }
 
 // CHECK: allocate_shared : tensor<32x9xf32>
-// CHECK: shuffle_reduce @add_add{{.*}} to 16 : f32
+// CHECK: shuffle_reduce(%{{.*}}) to 16 combiner=@add_add

xla/service/gpu/fusions/tests/reduce_column_small/s8_f32_32_v4.hlo

@@ -14,4 +14,4 @@ fusion {
 
 // CHECK: vector<4xf32>
 // CHECK: allocate_shared : tensor<16x33xf32>
-// CHECK: shuffle_reduce @add_add{{.*}} to 8 : f32
+// CHECK: shuffle_reduce(%{{.*}}) to 8 combiner=@add_add

xla/service/gpu/fusions/tests/reduce_multirow/f32_x8.hlo

@@ -16,5 +16,5 @@ fusion {
 // Multi-row reductions do not use shared memory.
 // CHECK-NOT: allocate_shared
 // There should be 8 elements per warp.
-// CHECK: shuffle_reduce {{.*}} to 2
+// CHECK: shuffle_reduce(%{{.*}}) to 2
 // CHECK-NOT: allocate_shared

xla/service/gpu/fusions/tests/reduce_row/inefficient_codegen.hlo

@@ -44,4 +44,4 @@ fusion {
 
 // reduce0 again, in the context of its status as a fusion hero:
 // CHECK:     tensor.extract %[[P1]][%[[RC]]]
-// CHECK:     shuffle_reduce @add_add(%{{.*}}) to 2
+// CHECK: shuffle_reduce(%{{.*}}) to 2 combiner=@add_add

xla/service/gpu/fusions/tests/reduce_row/mof_epilogue.hlo

@@ -28,16 +28,16 @@ fusion {
   ROOT tuple = (f32[8], f32[8], f32[8]) tuple(log, neg, abs)
 }
 
-// CHECK-DAG: shuffle_reduce @add_add
-// CHECK-DAG: shuffle_reduce @mul_mul
+// CHECK-DAG: shuffle_reduce(%{{.*}}) to 16 combiner=@add_add
+// CHECK-DAG: shuffle_reduce(%{{.*}}) to 16 combiner=@mul_mul
 // CHECK: allocate_shared
 // CHECK: allocate_shared
 // CHECK: sync_threads
-// CHECK-DAG: %[[ADDED:.*]] = xla_gpu.shuffle_reduce @add_add
-// CHECK-DAG: %[[MULTIPLIED:.*]] = xla_gpu.shuffle_reduce @mul_mul
-// CHECK-DAG: %[[LOG:.*]] = math.log %[[ADDED]]
-// CHECK-DAG: %[[ABS:.*]] = math.absf %[[ADDED]]
-// CHECK-DAG: %[[NEG:.*]] = arith.negf %[[MULTIPLIED]]
+// CHECK-DAG: %[[SUM:.*]] = xla_gpu.shuffle_reduce(%{{.*}}) to 16 combiner=@add_add
+// CHECK-DAG: %[[PROD:.*]] = xla_gpu.shuffle_reduce(%{{.*}}) to 16 combiner=@mul_mul
+// CHECK-DAG: %[[LOG:.*]] = math.log %[[SUM]]
+// CHECK-DAG: %[[ABS:.*]] = math.absf %[[SUM]]
+// CHECK-DAG: %[[NEG:.*]] = arith.negf %[[PROD]]
 // CHECK-DAG: xla_gpu.predicated_insert %[[LOG]]
 // CHECK-DAG: xla_gpu.predicated_insert %[[ABS]]
 // CHECK-DAG: xla_gpu.predicated_insert %[[NEG]]

xla/service/gpu/fusions/transforms/lower_xla_gpu_to_scf.cc

@@ -186,7 +186,7 @@ struct RewriteShuffleReduce : mlir::OpRewritePattern<ShuffleReduceOp> {
         args.push_back(shuffle(value));
       }
       values = b.create<PureCallOp>(op.getResultTypes(),
-                                    op.getReducerAttr().getAttr(), args)
+                                    op.getCombinerAttr().getAttr(), args)
                    .getResults();
     }
     rewriter.replaceOp(op, values);

xla/service/gpu/fusions/transforms/tests/lower_xla_gpu_to_scf.mlir

@@ -1,12 +1,12 @@
 // RUN: mlir_fusions_opt %s -xla-gpu-lower-xla-gpu-to-scf --split-input-file  \
 // RUN: | FileCheck %s
 
-func.func @reducer(%a: f32, %b: i32, %c: f32, %d: i32) -> (f32, i32) {
+func.func @combiner(%a: f32, %b: i32, %c: f32, %d: i32) -> (f32, i32) {
   return %a, %b : f32, i32
 }
 
 func.func @shuffler(%a: f32, %b: i32) -> (f32, i32) {
-  %ret:2 = xla_gpu.shuffle_reduce @reducer(%a, %b) to 4 : f32, i32
+  %ret:2 = xla_gpu.shuffle_reduce (%a, %b) to 4 combiner=@combiner: f32, i32
   return %ret#0, %ret#1 : f32, i32
 }
 // CHECK: @shuffler(%[[A:.*]]: f32, %[[B:.*]]: i32)
@@ -16,23 +16,23 @@ func.func @shuffler(%a: f32, %b: i32) -> (f32, i32) {
 // CHECK-DAG: %[[C32:.*]] = arith.constant 32
 // CHECK: %[[A4H:.*]], {{.*}} = gpu.shuffle down %[[A]], %[[C4]], %[[C32]]
 // CHECK: %[[B4H:.*]], {{.*}} = gpu.shuffle down %[[B]], %[[C4]], %[[C32]]
-// CHECK: %[[AB4_0:.*]], %[[AB4_1:.*]] = xla_gpu.pure_call @reducer(%[[A]], %[[B]], %[[A4H]], %[[B4H]])
+// CHECK: %[[AB4_0:.*]], %[[AB4_1:.*]] = xla_gpu.pure_call @combiner(%[[A]], %[[B]], %[[A4H]], %[[B4H]])
 // CHECK: %[[A2H:.*]], {{.*}} = gpu.shuffle down %[[AB4_0]], %[[C2]], %[[C32]]
 // CHECK: %[[B2H:.*]], {{.*}} = gpu.shuffle down %[[AB4_1]], %[[C2]], %[[C32]]
-// CHECK: %[[AB2_0:.*]], %[[AB2_1:.*]] = xla_gpu.pure_call @reducer(%[[AB4_0]], %[[AB4_1]], %[[A2H]], %[[B2H]])
+// CHECK: %[[AB2_0:.*]], %[[AB2_1:.*]] = xla_gpu.pure_call @combiner(%[[AB4_0]], %[[AB4_1]], %[[A2H]], %[[B2H]])
 // CHECK: %[[A1H:.*]], {{.*}} = gpu.shuffle down %[[AB2_0]], %[[C1]], %[[C32]]
 // CHECK: %[[B1H:.*]], {{.*}} = gpu.shuffle down %[[AB2_1]], %[[C1]], %[[C32]]
-// CHECK: %[[AB1_0:.*]], %[[AB1_1:.*]] = xla_gpu.pure_call @reducer(%[[AB2_0]], %[[AB2_1]], %[[A1H]], %[[B1H]])
+// CHECK: %[[AB1_0:.*]], %[[AB1_1:.*]] = xla_gpu.pure_call @combiner(%[[AB2_0]], %[[AB2_1]], %[[A1H]], %[[B1H]])
 // CHECK: return %[[AB1_0]], %[[AB1_1]]
 
 // -----
 
-func.func @reducer(%a: f64, %b: f64) -> f64 {
+func.func @combiner(%a: f64, %b: f64) -> f64 {
   return %a : f64
 }
 
 func.func @shuffler(%a: f64) -> f64 {
-  %ret = xla_gpu.shuffle_reduce @reducer(%a) to 1 : f64
+  %ret = xla_gpu.shuffle_reduce(%a) to 1 combiner=@combiner : f64
   return %ret : f64
 }
 // CHECK: @shuffler(%[[A:.*]]: f64
@@ -41,25 +41,25 @@ func.func @shuffler(%a: f64) -> f64 {
 
 // -----
 
-func.func @reducer(%a: complex<f64>, %b: complex<f64>) -> complex<f64> {
+func.func @combiner(%a: complex<f64>, %b: complex<f64>) -> complex<f64> {
   return %a : complex<f64>
 }
 
 func.func @shuffler(%a: complex<f64>) -> complex<f64> {
-  %ret = xla_gpu.shuffle_reduce @reducer(%a) to 1 : complex<f64>
+  %ret = xla_gpu.shuffle_reduce(%a) to 1 combiner=@combiner : complex<f64>
   return %ret : complex<f64>
 }
 // CHECK: @shuffler
 // CHECK-COUNT-4: gpu.shuffle down {{.*}}, %[[C1]]
 
 // -----
 
-func.func @reducer(%a: ui64, %b: ui64) -> ui64 {
+func.func @combiner(%a: ui64, %b: ui64) -> ui64 {
   return %a : ui64
 }
 
 func.func @shuffler(%a: ui64) -> ui64 {
-  %ret = xla_gpu.shuffle_reduce @reducer(%a) to 1 : ui64
+  %ret = xla_gpu.shuffle_reduce (%a) to 1 combiner=@combiner : ui64
   return %ret : ui64
 }
 // CHECK: @shuffler
@@ -68,12 +68,12 @@ func.func @shuffler(%a: ui64) -> ui64 {
 
 // -----
 
-func.func @reducer(%a: i8, %b: i8) -> i8 {
+func.func @combiner(%a: i8, %b: i8) -> i8 {
   return %a : i8
 }
 
 func.func @shuffler_i8(%a: i8) -> i8 {
-  %ret = xla_gpu.shuffle_reduce @reducer(%a) to 1 : i8
+  %ret = xla_gpu.shuffle_reduce (%a) to 1 combiner=@combiner : i8
   return %ret : i8
 }
 // CHECK: @shuffler_i8(