diff --git a/mlir/test/Dialect/ArmSME/tile-allocation-liveness.mlir b/mlir/test/Dialect/ArmSME/tile-allocation-liveness.mlir new file mode 100644 index 0000000000000..2dedcb2fbc24e --- /dev/null +++ b/mlir/test/Dialect/ArmSME/tile-allocation-liveness.mlir @@ -0,0 +1,183 @@ +// RUN: mlir-opt %s -allocate-arm-sme-tiles -split-input-file -verify-diagnostics | FileCheck %s --check-prefix=CHECK-BAD + +// This file tests some aspects of liveness issues in the SME tile allocator. +// These tests were designed with a new liveness-based tile allocator in mind +// (where the names of test cases make more sense), with the current tile +// allocator these tests all give incorrect results (which is documented by +// `CHECK-BAD`). + +// Incorrect result! The second `move_vector_to_tile_slice` overwrites the first (which is still live). +// +// CHECK-BAD-LABEL: @constant_with_multiple_users +// CHECK-BAD: %[[ZERO_TILE:.*]] = arm_sme.zero {tile_id = 0 : i32} : vector<[4]x[4]xf32> +// CHECK-BAD: %[[INSERT_TILE_1:.*]] = arm_sme.move_vector_to_tile_slice %{{.*}} {tile_id = 0 : i32} : vector<[4]xf32> into vector<[4]x[4]xf32> +// CHECK-BAD: %[[INSERT_TILE_0:.*]] = arm_sme.move_vector_to_tile_slice %{{.*}} {tile_id = 0 : i32} : vector<[4]xf32> into vector<[4]x[4]xf32> +func.func @constant_with_multiple_users(%a: vector<[4]xf32>, %b: vector<[4]xf32>, %index: index) { + %zero = arm_sme.zero : vector<[4]x[4]xf32> + %tile_a = arm_sme.move_vector_to_tile_slice %a, %zero, %index : vector<[4]xf32> into vector<[4]x[4]xf32> + %tile_b = arm_sme.move_vector_to_tile_slice %b, %zero, %index : vector<[4]xf32> into vector<[4]x[4]xf32> + "test.some_use"(%tile_a) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_b) : (vector<[4]x[4]xf32>) -> () + return +} + +// ----- + +// (No tile IDs -- the current tile allocator ignores this case) + +// CHECK-BAD-LABEL: @value_with_multiple_users +// CHECK-BAD-NOT: tile_id +func.func @value_with_multiple_users(%tile: vector<[4]x[4]xf32>, %a: vector<[4]xf32>, %b: vector<[4]xf32>, %index: index) { + // A future allocator should error here (as `%tile` would need to be copied). + %tile_a = arm_sme.move_vector_to_tile_slice %a, %tile, %index : vector<[4]xf32> into vector<[4]x[4]xf32> + %tile_b = arm_sme.move_vector_to_tile_slice %b, %tile, %index : vector<[4]xf32> into vector<[4]x[4]xf32> + "test.some_use"(%tile_a) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_b) : (vector<[4]x[4]xf32>) -> () + return +} + +// ----- + +// CHECK-BAD-LABEL: @reuse_tiles_after_initial_use +func.func @reuse_tiles_after_initial_use() { + // CHECK-BAD: arm_sme.get_tile {tile_id = 0 : i32} + // CHECK-BAD: arm_sme.get_tile {tile_id = 1 : i32} + // CHECK-BAD: arm_sme.get_tile {tile_id = 2 : i32} + // CHECK-BAD: arm_sme.get_tile {tile_id = 3 : i32} + %tile_a = arm_sme.get_tile : vector<[4]x[4]xf32> + %tile_b = arm_sme.get_tile : vector<[4]x[4]xf32> + %tile_c = arm_sme.get_tile : vector<[4]x[4]xf32> + %tile_d = arm_sme.get_tile : vector<[4]x[4]xf32> + "test.dummy"(): () -> () + "test.dummy"(): () -> () + "test.dummy"(): () -> () + "test.some_use"(%tile_a) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_b) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_c) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_d) : (vector<[4]x[4]xf32>) -> () + // -> Spills after the fourth tile (unnecessary): + // CHECK-BAD: arm_sme.zero {tile_id = 16 : i32} + // CHECK-BAD: arm_sme.zero {tile_id = 17 : i32} + // CHECK-BAD: arm_sme.zero {tile_id = 18 : i32} + // CHECK-BAD: arm_sme.zero {tile_id = 19 : i32} + // Unnecessary spills: + // expected-warning @below {{failed to allocate SME virtual tile to operation, all tile operations will go through memory, expect degraded performance}} + %tile_1 = arm_sme.zero : vector<[4]x[4]xf32> + // expected-warning @below {{failed to allocate SME virtual tile to operation, all tile operations will go through memory, expect degraded performance}} + %tile_2 = arm_sme.zero : vector<[4]x[4]xf32> + // expected-warning @below {{failed to allocate SME virtual tile to operation, all tile operations will go through memory, expect degraded performance}} + %tile_3 = arm_sme.zero : vector<[4]x[4]xf32> + // expected-warning @below {{failed to allocate SME virtual tile to operation, all tile operations will go through memory, expect degraded performance}} + %tile_4 = arm_sme.zero : vector<[4]x[4]xf32> + "test.dummy"(): () -> () + "test.dummy"(): () -> () + "test.dummy"(): () -> () + "test.some_use"(%tile_1) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_2) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_3) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_4) : (vector<[4]x[4]xf32>) -> () + return +} + +// ----- + +// Incorrect result! Both branches should yield the result via the same tile. +// +// CHECK-BAD-LABEL: @non_overlapping_branches +// CHECK-BAD: arm_sme.zero {tile_id = 0 : i32} : vector<[4]x[4]xf32> +// CHECK-BAD: arm_sme.get_tile {tile_id = 1 : i32} : vector<[4]x[4]xf32> +func.func @non_overlapping_branches(%cond: i1) { + %tile = scf.if %cond -> vector<[4]x[4]xf32> { + %zero = arm_sme.zero : vector<[4]x[4]xf32> + scf.yield %zero : vector<[4]x[4]xf32> + } else { + %undef = arm_sme.get_tile : vector<[4]x[4]xf32> + scf.yield %undef : vector<[4]x[4]xf32> + } + "test.some_use"(%tile) : (vector<[4]x[4]xf32>) -> () + return +} + +// ----- + +// Incorrect result! Everything assigned to tile 0 (which means values that are still live are overwritten). +// +// CHECK-BAD-LABEL: @constant_loop_init_with_multiple_users +// CHECK-BAD: arm_sme.zero {tile_id = 0 : i32} : vector<[4]x[4]xf32> +// CHECK-BAD: arm_sme.move_vector_to_tile_slice {{.*}} {tile_id = 0 : i32} : vector<[4]xf32> into vector<[4]x[4]xf32> +// CHECK-BAD: arm_sme.move_vector_to_tile_slice {{.*}} {tile_id = 0 : i32} : vector<[4]xf32> into vector<[4]x[4]xf32> +func.func @constant_loop_init_with_multiple_users(%a: vector<[4]xf32>, %b: vector<[4]xf32>) { + %c0 = arith.constant 0 : index + %c1 = arith.constant 1 : index + %c10 = arith.constant 10 : index + %init = arm_sme.zero : vector<[4]x[4]xf32> + %tile_a = scf.for %i = %c0 to %c10 step %c1 iter_args(%iter = %init) -> vector<[4]x[4]xf32> { + %new_tile = arm_sme.move_vector_to_tile_slice %a, %iter, %i : vector<[4]xf32> into vector<[4]x[4]xf32> + scf.yield %new_tile : vector<[4]x[4]xf32> + } + %tile_b = scf.for %i = %c0 to %c10 step %c1 iter_args(%iter = %init) -> vector<[4]x[4]xf32> { + %new_tile = arm_sme.move_vector_to_tile_slice %a, %iter, %i : vector<[4]xf32> into vector<[4]x[4]xf32> + scf.yield %new_tile : vector<[4]x[4]xf32> + } + "test.some_use"(%tile_a) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_b) : (vector<[4]x[4]xf32>) -> () + return +} + +// ----- + +// Incorrect result! Everything assigned to tile 0 (which means values that are still live are overwritten). +// +// CHECK-BAD-LABEL: @run_out_of_tiles_but_avoid_spill +// CHECK-BAD: arm_sme.zero {tile_id = 0 : i32} +// CHECK-BAD-COUNT-4: arm_sme.move_vector_to_tile_slice {{.*}} {tile_id = 0 : i32} : vector<[4]xf32> into vector<[4]x[4]xf32> +func.func @run_out_of_tiles_but_avoid_spill(%a: vector<[4]xf32>, %b: vector<[4]xf32>, %c: vector<[4]xf32>, %d: vector<[4]xf32>) { + %init = arm_sme.zero : vector<[4]x[4]xf32> + %c0 = arith.constant 0 : index + %c1 = arith.constant 1 : index + %c10 = arith.constant 10 : index + scf.for %i = %c0 to %c10 step %c1 { + %tile_a, %tile_b, %tile_c, %tile_d = scf.for %j = %c0 to %c10 step %c1 + iter_args(%iter_a = %init, %iter_b = %init, %iter_c = %init, %iter_d = %init) + -> (vector<[4]x[4]xf32>, vector<[4]x[4]xf32> , vector<[4]x[4]xf32> , vector<[4]x[4]xf32>) { + %new_a = arm_sme.move_vector_to_tile_slice %a, %iter_a, %i : vector<[4]xf32> into vector<[4]x[4]xf32> + %new_b = arm_sme.move_vector_to_tile_slice %b, %iter_b, %i : vector<[4]xf32> into vector<[4]x[4]xf32> + %new_c = arm_sme.move_vector_to_tile_slice %c, %iter_c, %i : vector<[4]xf32> into vector<[4]x[4]xf32> + %new_d = arm_sme.move_vector_to_tile_slice %d, %iter_d, %i : vector<[4]xf32> into vector<[4]x[4]xf32> + scf.yield %new_a, %new_b, %new_c, %new_d : vector<[4]x[4]xf32>, vector<[4]x[4]xf32>, vector<[4]x[4]xf32>, vector<[4]x[4]xf32> + } + "test.some_use"(%tile_a) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_b) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_c) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_d) : (vector<[4]x[4]xf32>) -> () + } + return +} + +// ----- + +// Incorrect result! Everything other than zero assigned to tile 1 (which means values that are still live are overwritten). +// +// CHECK-BAD-LABEL: @avoidable_spill +// CHECK-BAD: arm_sme.zero {tile_id = 0 : i32} +// CHECK-BAD: arm_sme.get_tile {tile_id = 1 : i32} +// CHECK-BAD-COUNT-4: arm_sme.move_vector_to_tile_slice {{.*}} {tile_id = 1 : i32} +func.func @avoidable_spill(%a: vector<[4]xf32>, %b: vector<[4]xf32>, %c: vector<[4]xf32>, %d: vector<[4]xf32>) { + %zero = arm_sme.zero : vector<[4]x[4]xf32> + %tile = arm_sme.get_tile : vector<[4]x[4]xf32> + %c0 = arith.constant 0 : index + %c1 = arith.constant 1 : index + %c10 = arith.constant 10 : index + scf.for %i = %c0 to %c10 step %c1 { + "test.some_use"(%zero) : (vector<[4]x[4]xf32>) -> () + %tile_a = arm_sme.move_vector_to_tile_slice %a, %tile, %c0 : vector<[4]xf32> into vector<[4]x[4]xf32> + %tile_b = arm_sme.move_vector_to_tile_slice %b, %tile, %c0 : vector<[4]xf32> into vector<[4]x[4]xf32> + %tile_c = arm_sme.move_vector_to_tile_slice %c, %tile, %c0 : vector<[4]xf32> into vector<[4]x[4]xf32> + %tile_d = arm_sme.move_vector_to_tile_slice %d, %tile, %c0 : vector<[4]xf32> into vector<[4]x[4]xf32> + "test.some_use"(%tile_a) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_b) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_c) : (vector<[4]x[4]xf32>) -> () + "test.some_use"(%tile_d) : (vector<[4]x[4]xf32>) -> () + } + return +}