[webgpu] Update INT_DIV (#7792)

Author: hujiajie

tfjs-backend-webgpu/src/binary_op_util.ts

@@ -23,9 +23,9 @@ export enum BinaryOpType {
   DIV,
   ELU_DER,
   EQUAL,
+  FLOOR_DIV,
   GREATER,
   GREATER_EQUAL,
-  INT_DIV,
   LESS,
   LESS_EQUAL,
   LOGICAL_AND,
@@ -56,6 +56,13 @@ const EQUAL = `
   let one = sign(b) * 0 + 1;
   let resultTemp = select(zero, one, a == b);
 `;
+const FLOOR_DIV = `
+  let remainder =
+      select(a % b, round(a % b), (round(a) == a) & (round(b) == b));
+  let quotient = (a - remainder) / b;
+  let resultTemp =
+      round(select(quotient, quotient - 1, sign(remainder) == -sign(b)));
+`;
 const GREATER = `
   let zero = sign(a) * 0 + 0;
   let one = sign(b) * 0 + 1;
@@ -66,36 +73,6 @@ const GREATER_EQUAL = `
   let one = sign(b) * 0 + 1;
   let resultTemp = select(zero, one, a >= b);
 `;
-
-const INT_DIV = `
-  let s = sign(a) * sign(b);
-  let ia = i32(round(a));
-  let ib = i32(round(b));
-  return f32(idiv(ia, ib, s));
-`;
-const INT_DIV_VEC4 = `
-  let ia = vec4<i32>(round(a));
-  let ib = vec4<i32>(round(b));
-  let cond = ib != vec4<i32>(0);
-  var resultTemp = vec4<i32>(0);
-  let s = sign(a) * sign(b);
-
-  // Windows (D3D) wants guaranteed non-zero int division at compile-time.
-  if (cond[0]) {
-    resultTemp[0] = idiv(ia[0], ib[0], s[0]);
-  }
-  if (cond[1]) {
-    resultTemp[1] = idiv(ia[1], ib[1], s[1]);
-  }
-  if (cond[2]) {
-    resultTemp[2] = idiv(ia[2], ib[2], s[2]);
-  }
-  if (cond[3]) {
-    resultTemp[3] = idiv(ia[3], ib[3], s[3]);
-  }
-  return vec4<f32>(resultTemp);
-`;
-
 const LESS = `
   let zero = sign(a) * 0 + 0;
   let one = sign(b) * 0 + 1;
@@ -265,14 +242,15 @@ export function getBinaryOpString(
     case BinaryOpType.EQUAL:
       doOpSnippet = EQUAL;
       break;
+    case BinaryOpType.FLOOR_DIV:
+      doOpSnippet = FLOOR_DIV;
+      break;
     case BinaryOpType.GREATER:
       doOpSnippet = GREATER;
       break;
     case BinaryOpType.GREATER_EQUAL:
       doOpSnippet = GREATER_EQUAL;
       break;
-    case BinaryOpType.INT_DIV:
-      return useVec4 ? INT_DIV_VEC4 : INT_DIV;
     case BinaryOpType.LESS:
       doOpSnippet = LESS;
       break;

tfjs-backend-webgpu/src/kernels/FloorDiv.ts

@@ -21,9 +21,11 @@ import {BinaryOpType} from '../binary_op_util';
 import {binaryKernelFunc} from '../kernel_utils/kernel_funcs_utils';
 import {floorDivImplCPU} from '../kernel_utils/shared';
 
-export const floorDiv =
-    binaryKernelFunc({opType: BinaryOpType.INT_DIV,
-                      cpuKernelImpl: floorDivImplCPU, dtype: 'int32'});
+export const floorDiv = binaryKernelFunc({
+  opType: BinaryOpType.FLOOR_DIV,
+  cpuKernelImpl: floorDivImplCPU,
+  dtype: 'int32'
+});
 
 export const floorDivConfig: KernelConfig = {
   kernelName: FloorDiv,

tfjs-backend-webgpu/src/setup_test.ts

@@ -168,13 +168,6 @@ const TEST_FILTERS: TestFilter[] = [
       'indices invalid',
     ],
   },
-  {
-    startsWith: 'floorDiv ',
-    excludes: [
-      // float32 inputs with nonzero fractional part should not be rounded
-      'floorDiv float32',
-    ],
-  },
 
   // exclude unsupported kernels and to be fixed cases
   {

tfjs-backend-webgpu/src/webgpu_program.ts

@@ -417,15 +417,6 @@ const commonSnippet = `
     return coords.x*shapeStrides.x + coords.y*shapeStrides.y + coords.z*shapeStrides.z + coords.w*shapeStrides.w + coords.u*shapeStrides.u + coords.v*shapeStrides.v;
   }
 
-  fn idiv(a: i32, b: i32, sign: f32) -> i32 {
-    var res: i32 = a / b;
-    let modulo: i32 = a % b;
-    if (sign < 0. && modulo != 0) {
-      res = res - 1;
-    }
-    return res;
-  }
-
   // NaN defination in IEEE 754-1985 is :
   //   - sign = either 0 or 1.
   //   - biased exponent = all 1 bits.