mlir/test/Dialect/Loops/parallel-loop-fusion.mlir

// RUN: mlir-opt %s -pass-pipeline='func(parallel-loop-fusion)' -split-input-file | FileCheck %s --dump-input-on-failure

func @fuse_empty_loops() {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @fuse_empty_loops
// CHECK:        [[C2:%.*]] = constant 2 : index
// CHECK:        [[C0:%.*]] = constant 0 : index
// CHECK:        [[C1:%.*]] = constant 1 : index
// CHECK:        loop.parallel ([[I:%.*]], [[J:%.*]]) = ([[C0]], [[C0]])
// CHECK-SAME:       to ([[C2]], [[C2]]) step ([[C1]], [[C1]]) {
// CHECK:          loop.yield
// CHECK:        }
// CHECK-NOT:    loop.parallel

// -----

func @fuse_two(%A: memref<2x2xf32>, %B: memref<2x2xf32>,
                    %C: memref<2x2xf32>, %result: memref<2x2xf32>) {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  %sum = alloc()  : memref<2x2xf32>
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %B_elem = load %B[%i, %j] : memref<2x2xf32>
    %C_elem = load %C[%i, %j] : memref<2x2xf32>
    %sum_elem = addf %B_elem, %C_elem : f32
    store %sum_elem, %sum[%i, %j] : memref<2x2xf32>
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %sum_elem = load %sum[%i, %j] : memref<2x2xf32>
    %A_elem = load %A[%i, %j] : memref<2x2xf32>
    %product_elem = mulf %sum_elem, %A_elem : f32
    store %product_elem, %result[%i, %j] : memref<2x2xf32>
    loop.yield
  }
  dealloc %sum : memref<2x2xf32>
  return
}
// CHECK-LABEL: func @fuse_two
// CHECK-SAME:   ([[A:%.*]]: {{.*}}, [[B:%.*]]: {{.*}}, [[C:%.*]]: {{.*}},
// CHECK-SAME:    [[RESULT:%.*]]: {{.*}}) {
// CHECK:      [[C2:%.*]] = constant 2 : index
// CHECK:      [[C0:%.*]] = constant 0 : index
// CHECK:      [[C1:%.*]] = constant 1 : index
// CHECK:      [[SUM:%.*]] = alloc()
// CHECK:      loop.parallel ([[I:%.*]], [[J:%.*]]) = ([[C0]], [[C0]])
// CHECK-SAME:     to ([[C2]], [[C2]]) step ([[C1]], [[C1]]) {
// CHECK:        [[B_ELEM:%.*]] = load [[B]]{{\[}}[[I]], [[J]]]
// CHECK:        [[C_ELEM:%.*]] = load [[C]]{{\[}}[[I]], [[J]]]
// CHECK:        [[SUM_ELEM:%.*]] = addf [[B_ELEM]], [[C_ELEM]]
// CHECK:        store [[SUM_ELEM]], [[SUM]]{{\[}}[[I]], [[J]]]
// CHECK:        [[SUM_ELEM_:%.*]] = load [[SUM]]{{\[}}[[I]], [[J]]]
// CHECK:        [[A_ELEM:%.*]] = load [[A]]{{\[}}[[I]], [[J]]]
// CHECK:        [[PRODUCT_ELEM:%.*]] = mulf [[SUM_ELEM_]], [[A_ELEM]]
// CHECK:        store [[PRODUCT_ELEM]], [[RESULT]]{{\[}}[[I]], [[J]]]
// CHECK:        loop.yield
// CHECK:      }
// CHECK:      dealloc [[SUM]]

// -----

func @fuse_three(%lhs: memref<100x10xf32>, %rhs: memref<100xf32>,
                      %result: memref<100x10xf32>) {
  %c100 = constant 100 : index
  %c10 = constant 10 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  %broadcast_rhs = alloc() : memref<100x10xf32>
  %diff = alloc() : memref<100x10xf32>
  loop.parallel (%i, %j) = (%c0, %c0) to (%c100, %c10) step (%c1, %c1) {
    %rhs_elem = load %rhs[%i] : memref<100xf32>
    store %rhs_elem, %broadcast_rhs[%i, %j] : memref<100x10xf32>
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c100, %c10) step (%c1, %c1) {
    %lhs_elem = load %lhs[%i, %j] : memref<100x10xf32>
    %broadcast_rhs_elem = load %broadcast_rhs[%i, %j] : memref<100x10xf32>
    %diff_elem = subf %lhs_elem, %broadcast_rhs_elem : f32
    store %diff_elem, %diff[%i, %j] : memref<100x10xf32>
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c100, %c10) step (%c1, %c1) {
    %diff_elem = load %diff[%i, %j] : memref<100x10xf32>
    %exp_elem = exp %diff_elem : f32
    store %exp_elem, %result[%i, %j] : memref<100x10xf32>
    loop.yield
  }
  dealloc %broadcast_rhs : memref<100x10xf32>
  dealloc %diff : memref<100x10xf32>
  return
}
// CHECK-LABEL: func @fuse_three
// CHECK-SAME: ([[LHS:%.*]]: memref<100x10xf32>, [[RHS:%.*]]: memref<100xf32>,
// CHECK-SAME:  [[RESULT:%.*]]: memref<100x10xf32>) {
// CHECK:      [[C100:%.*]] = constant 100 : index
// CHECK:      [[C10:%.*]] = constant 10 : index
// CHECK:      [[C0:%.*]] = constant 0 : index
// CHECK:      [[C1:%.*]] = constant 1 : index
// CHECK:      [[BROADCAST_RHS:%.*]] = alloc()
// CHECK:      [[DIFF:%.*]] = alloc()
// CHECK:      loop.parallel ([[I:%.*]], [[J:%.*]]) = ([[C0]], [[C0]])
// CHECK-SAME:     to ([[C100]], [[C10]]) step ([[C1]], [[C1]]) {
// CHECK:        [[RHS_ELEM:%.*]] = load [[RHS]]{{\[}}[[I]]]
// CHECK:        store [[RHS_ELEM]], [[BROADCAST_RHS]]{{\[}}[[I]], [[J]]]
// CHECK:        [[LHS_ELEM:%.*]] = load [[LHS]]{{\[}}[[I]], [[J]]]
// CHECK:        [[BROADCAST_RHS_ELEM:%.*]] = load [[BROADCAST_RHS]]
// CHECK:        [[DIFF_ELEM:%.*]] = subf [[LHS_ELEM]], [[BROADCAST_RHS_ELEM]]
// CHECK:        store [[DIFF_ELEM]], [[DIFF]]{{\[}}[[I]], [[J]]]
// CHECK:        [[DIFF_ELEM_:%.*]] = load [[DIFF]]{{\[}}[[I]], [[J]]]
// CHECK:        [[EXP_ELEM:%.*]] = exp [[DIFF_ELEM_]]
// CHECK:        store [[EXP_ELEM]], [[RESULT]]{{\[}}[[I]], [[J]]]
// CHECK:        loop.yield
// CHECK:      }
// CHECK:      dealloc [[BROADCAST_RHS]]
// CHECK:      dealloc [[DIFF]]

// -----

func @do_not_fuse_nested_ploop1() {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.parallel (%k, %l) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
      loop.yield
    }
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @do_not_fuse_nested_ploop1
// CHECK:        loop.parallel
// CHECK:          loop.parallel
// CHECK:        loop.parallel

// -----

func @do_not_fuse_nested_ploop2() {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.parallel (%k, %l) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
      loop.yield
    }
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @do_not_fuse_nested_ploop2
// CHECK:        loop.parallel
// CHECK:        loop.parallel
// CHECK:          loop.parallel

// -----

func @do_not_fuse_loops_unmatching_num_loops() {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  loop.parallel (%i) = (%c0) to (%c2) step (%c1) {
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @do_not_fuse_loops_unmatching_num_loops
// CHECK:        loop.parallel
// CHECK:        loop.parallel

// -----

func @do_not_fuse_loops_with_side_effecting_ops_in_between() {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  %buffer  = alloc() : memref<2x2xf32>
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @do_not_fuse_loops_with_side_effecting_ops_in_between
// CHECK:        loop.parallel
// CHECK:        loop.parallel

// -----

func @do_not_fuse_loops_unmatching_iteration_space() {
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  %c2 = constant 2 : index
  %c4 = constant 4 : index
  loop.parallel (%i, %j) = (%c0, %c0) to (%c4, %c4) step (%c2, %c2) {
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @do_not_fuse_loops_unmatching_iteration_space
// CHECK:        loop.parallel
// CHECK:        loop.parallel

// -----

func @do_not_fuse_unmatching_write_read_patterns(
    %A: memref<2x2xf32>, %B: memref<2x2xf32>,
    %C: memref<2x2xf32>, %result: memref<2x2xf32>) {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  %common_buf = alloc() : memref<2x2xf32>
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %B_elem = load %B[%i, %j] : memref<2x2xf32>
    %C_elem = load %C[%i, %j] : memref<2x2xf32>
    %sum_elem = addf %B_elem, %C_elem : f32
    store %sum_elem, %common_buf[%i, %j] : memref<2x2xf32>
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %k = addi %i, %c1 : index
    %sum_elem = load %common_buf[%k, %j] : memref<2x2xf32>
    %A_elem = load %A[%i, %j] : memref<2x2xf32>
    %product_elem = mulf %sum_elem, %A_elem : f32
    store %product_elem, %result[%i, %j] : memref<2x2xf32>
    loop.yield
  }
  dealloc %common_buf : memref<2x2xf32>
  return
}
// CHECK-LABEL: func @do_not_fuse_unmatching_write_read_patterns
// CHECK:        loop.parallel
// CHECK:        loop.parallel

// -----

func @do_not_fuse_unmatching_read_write_patterns(
    %A: memref<2x2xf32>, %B: memref<2x2xf32>, %common_buf: memref<2x2xf32>) {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  %sum = alloc() : memref<2x2xf32>
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %B_elem = load %B[%i, %j] : memref<2x2xf32>
    %C_elem = load %common_buf[%i, %j] : memref<2x2xf32>
    %sum_elem = addf %B_elem, %C_elem : f32
    store %sum_elem, %sum[%i, %j] : memref<2x2xf32>
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %k = addi %i, %c1 : index
    %sum_elem = load %sum[%k, %j] : memref<2x2xf32>
    %A_elem = load %A[%i, %j] : memref<2x2xf32>
    %product_elem = mulf %sum_elem, %A_elem : f32
    store %product_elem, %common_buf[%j, %i] : memref<2x2xf32>
    loop.yield
  }
  dealloc %sum : memref<2x2xf32>
  return
}
// CHECK-LABEL: func @do_not_fuse_unmatching_read_write_patterns
// CHECK:        loop.parallel
// CHECK:        loop.parallel

// -----

func @do_not_fuse_loops_with_memref_defined_in_loop_bodies() {
  %c2 = constant 2 : index
  %c0 = constant 0 : index
  %c1 = constant 1 : index
  %buffer  = alloc() : memref<2x2xf32>
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    loop.yield
  }
  loop.parallel (%i, %j) = (%c0, %c0) to (%c2, %c2) step (%c1, %c1) {
    %A = subview %buffer[%c0, %c0][%c2, %c2][%c1, %c1]
      : memref<2x2xf32> to memref<?x?xf32, offset: ?, strides:[?, ?]>
    %A_elem = load %A[%i, %j] : memref<?x?xf32, offset: ?, strides:[?, ?]>
    loop.yield
  }
  "xla_lhlo.terminator"() : () -> ()
}
// CHECK-LABEL: func @do_not_fuse_loops_with_memref_defined_in_loop_bodies
// CHECK:        loop.parallel
// CHECK:        loop.parallel