Add BF16 support to reference model

* Upgrade Eigen to 3.4.0 (for bfloat16 support) and add work-
  arounds for reduce.any() and reduce.all() bugs (introduced
  between 3.3.7 and 3.4.0)
* Truncation to bfloat16 now performed in eval() methods

Signed-off-by: James Ward <james.ward@arm.com>
Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: If5f5c988d76d3d30790acf3b97081726b89205fe

1 files changed, 21 insertions, 8 deletions

diff --git a/reference_model/src/ops/image.cc b/reference_model/src/ops/image.cc
index cf1d9f7..66efee0 100644
--- a/reference_model/src/ops/image.cc
+++ b/reference_model/src/ops/image.cc
@@ -63,7 +63,7 @@ int OpResize<InDtype, OutDtype, resize_t>::checkTensorAttributes()
 
     if (this->mode == ResizeMode_BILINEAR)
     {
-        if (OutDtype != DType_INT32 && OutDtype != DType_INT48 && OutDtype != DType_FP32 && OutDtype != DType_FP16)
+        if (OutDtype != DType_INT32 && OutDtype != DType_INT48 && OutDtype != DType_FP32 && OutDtype != DType_FP16 && OutDtype != DType_BF16)
         {
             printNodeValidationError("OpResize: invalid data type for BILINEAR");
             return 1;
@@ -71,7 +71,7 @@ int OpResize<InDtype, OutDtype, resize_t>::checkTensorAttributes()
     }
     else
     {
-        if (OutDtype != DType_INT8 && OutDtype != DType_INT16 && OutDtype != DType_FP32 && OutDtype != DType_FP16)
+        if (OutDtype != DType_INT8 && OutDtype != DType_INT16 && OutDtype != DType_FP32 && OutDtype != DType_FP16 && OutDtype != DType_BF16)
         {
             printNodeValidationError("OpResize: invalid data type for NEAREST");
             return 1;
@@ -159,15 +159,15 @@ int OpResize<InDtype, OutDtype, resize_t>::eval()
 
                     resize_t dy;
                     resize_t dx;
-                    if (std::is_floating_point<resize_t>::value)
+                    if (std::is_floating_point<resize_t>::value || (typeid(resize_t) == typeid(Eigen::bfloat16)))
                     {
-                        dy = fy - iy;
-                        dx = fx - ix;
+                        dy = (resize_t)(fy - iy);
+                        dx = (resize_t)(fx - ix);
                     }
                     else
                     {
-                        dy = y - (iy * scale_y_n);
-                        dx = x - (ix * scale_x_n);
+                        dy = (resize_t)(y - (iy * scale_y_n));
+                        dx = (resize_t)(x - (ix * scale_x_n));
                     }
 
                     int32_t iy0 = MAX(iy, 0);
@@ -190,6 +190,15 @@ int OpResize<InDtype, OutDtype, resize_t>::eval()
                             acc += (OutEigenType)v10 * dy * (1.0 - dx);
                             acc += (OutEigenType)v11 * dy * dx;
                         }
+                        else if ((typeid(resize_t) == typeid(Eigen::bfloat16)))
+                        {
+                            Eigen::bfloat16 bf16_acc;
+                            bf16_acc = (Eigen::bfloat16)v00 * (Eigen::bfloat16)(1.0 - dy) * (Eigen::bfloat16)(1.0 - dx);
+                            bf16_acc += (Eigen::bfloat16)v01 * (Eigen::bfloat16)(1.0 - dy) * (Eigen::bfloat16)dx;
+                            bf16_acc += (Eigen::bfloat16)v10 * (Eigen::bfloat16)dy * (Eigen::bfloat16)(1.0 - dx);
+                            bf16_acc += (Eigen::bfloat16)v11 * (Eigen::bfloat16)dy * (Eigen::bfloat16)dx;
+                            acc = (float)bf16_acc;
+                        }
                         else
                         {
                             acc = (OutEigenType)v00 * (scale_y_n - dy) * (scale_x_n - dx);
@@ -201,7 +210,7 @@ int OpResize<InDtype, OutDtype, resize_t>::eval()
                     else
                     {
                         ASSERT_MSG(mode == ResizeMode_NEAREST, "OpResize: invalid mode");
-                        if (std::is_floating_point<resize_t>::value)
+                        if (std::is_floating_point<resize_t>::value || (typeid(resize_t) == typeid(Eigen::bfloat16)))
                         {
                             iy = (dy >= 0.5) ? iy1 : iy0;
                             ix = (dx >= 0.5) ? ix1 : ix0;
@@ -213,6 +222,9 @@ int OpResize<InDtype, OutDtype, resize_t>::eval()
                         }
                         acc = in->getTensor()(b, iy, ix, c);
                     }
+                    if ((typeid(resize_t) == typeid(Eigen::bfloat16))) {
+                        ASSERT_MSG(checkValidBFloat(acc), "Resize accumulator float value is not a valid bfloat16 value.");
+                    }
                     out->getTensor()(b, oy, ox, c) = acc;
                 }
 
@@ -225,4 +237,5 @@ DEF_INSTANTIATE_THREE_TYPE(OpResize, INT8, INT8, int16_t);
 DEF_INSTANTIATE_THREE_TYPE(OpResize, INT16, INT48, int16_t);
 DEF_INSTANTIATE_THREE_TYPE(OpResize, INT16, INT16, int16_t);
 DEF_INSTANTIATE_THREE_TYPE(OpResize, FP16, FP16, float);
+DEF_INSTANTIATE_THREE_TYPE(OpResize, BF16, BF16, Eigen::bfloat16);
 DEF_INSTANTIATE_THREE_TYPE(OpResize, FP32, FP32, float);