Deprecated BF16 support in DepthConvert

* Removed BF16 validation tests for DepthConvert

* Revert back to using inline assembly to convert to/from BF16

* Resolves COMPMID-5800

Change-Id: I803b2ad19ead297417f780c97c5b724cca6b394c
Signed-off-by: Pablo Marquez Tello <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/8929
Reviewed-by: Jakub Sujak <jakub.sujak@arm.com>
Reviewed-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>

4 files changed, 88 insertions, 37 deletions

diff --git a/src/core/NEON/wrapper/intrinsics/cvt.h b/src/core/NEON/wrapper/intrinsics/cvt.h
index c75d43dbf2..1c77a9e9f0 100644
--- a/src/core/NEON/wrapper/intrinsics/cvt.h
+++ b/src/core/NEON/wrapper/intrinsics/cvt.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2022 Arm Limited.
+ * Copyright (c) 2020, 2022-2023 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -87,6 +87,26 @@ vcvta(const float32x4_t &a)
     return vcvtaq_s32_f32(a);
 }
 #endif //__aarch64__
+
+#if defined(ARM_COMPUTE_ENABLE_BF16)
+/** Convert 2x128-bit floating point vectors into 1x128-bit bfloat16 vector
+ *
+ * @param[in]     inptr  Pointer to the input memory to load values from
+ * @param[in,out] outptr Pointer to the output memory to store values to
+ */
+inline void vcvt_bf16_f32(const float *inptr, uint16_t *outptr)
+{
+    __asm __volatile(
+        "ldp    q0, q1, [%[inptr]]\n"
+        ".inst  0xea16800\n"  // BFCVTN v0, v0
+        ".inst  0x4ea16820\n" // BFCVTN2 v0, v1
+        "str    q0, [%[outptr]]\n"
+        : [inptr] "+r"(inptr)
+        : [outptr] "r"(outptr)
+        : "v0", "v1", "memory");
+}
+#endif /* defined(ARM_COMPUTE_ENABLE_BF16) */
+
 } // namespace wrapper
 } // namespace arm_compute
 #endif /* ARM_COMPUTE_WRAPPER_CVT_H */
diff --git a/src/cpu/kernels/CpuCastKernel.h b/src/cpu/kernels/CpuCastKernel.h
index 95d46fad23..de4ace2140 100644
--- a/src/cpu/kernels/CpuCastKernel.h
+++ b/src/cpu/kernels/CpuCastKernel.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2022 Arm Limited.
+ * Copyright (c) 2016-2023 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -62,6 +62,8 @@ public:
      * @param[in]  src    The src tensor to convert. Data types supported: QASYMM8_SIGNED/QASYMM8/U8/U16/S16/BFLOAT16/F16/F32.
      * @param[out] dst    The dst tensor. Data types supported: QASYMM8_SIGNED/QASYMM8/U8/U16/S16/U32/S32/BFLOAT16/F16/F32.
      * @param[in]  policy Conversion policy.
+     *
+     * @deprecated Support for BFLOAT16 will be removed in 23.05 release
      */
     void configure(const ITensorInfo *src, ITensorInfo *dst, ConvertPolicy policy);
     /** Static function to check if given info will lead to a valid configuration
diff --git a/src/cpu/kernels/cast/generic/neon/bfloat16.cpp b/src/cpu/kernels/cast/generic/neon/bfloat16.cpp
index 942bdfae61..91c15be279 100644
--- a/src/cpu/kernels/cast/generic/neon/bfloat16.cpp
+++ b/src/cpu/kernels/cast/generic/neon/bfloat16.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2022 Arm Limited.
+ * Copyright (c) 2016-2023 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -24,8 +24,10 @@
 #if defined(ARM_COMPUTE_ENABLE_BF16)
 
 #include "arm_compute/core/TensorInfo.h"
+#include "src/core/NEON/wrapper/wrapper.h"
 #include "src/cpu/kernels/CpuCastKernel.h"
 #include "src/cpu/kernels/cast/list.h"
+#include "support/SaturateCast.h"
 
 namespace arm_compute
 {
@@ -36,9 +38,9 @@ void neon_fp32_to_bfloat16_cast(const ITensor *_src, ITensor *_dst, const Thread
     ARM_COMPUTE_UNUSED(info);
     ARM_COMPUTE_UNUSED(_policy);
 
-    const auto    window_start_x = static_cast<int>(window.x().start());
-    const auto    window_end_x   = static_cast<int>(window.x().end());
-    constexpr int window_step_x  = 8;
+    const auto window_start_x = static_cast<int>(window.x().start());
+    const auto window_end_x   = static_cast<int>(window.x().end());
+    const int  window_step_x  = 16;
 
     ARM_COMPUTE_ERROR_ON_NULLPTR(_src, _dst);
     ARM_COMPUTE_ERROR_ON(_src == _dst);
@@ -50,23 +52,25 @@ void neon_fp32_to_bfloat16_cast(const ITensor *_src, ITensor *_dst, const Thread
 
     Iterator src(_src, win);
     Iterator dst(_dst, win);
+
     /* Down-conversion F32 -> BFLOAT16 */
     execute_window_loop(win, [&](const Coordinates &)
     {
-        const auto src_ptr     = reinterpret_cast<const float *>(src.ptr());
-        const auto dst_ptr     = reinterpret_cast<bfloat16_t *>(dst.ptr());
-        int        x           = window_start_x;
-        const int  right_bound = (window_end_x - window_step_x);
-        for(; x <= right_bound; x += window_step_x)
+        const auto src_ptr = reinterpret_cast<const float *>(src.ptr());
+        const auto dst_ptr = reinterpret_cast<bfloat16 *>(dst.ptr());
+
+        int x = window_start_x;
+        for(; x <= (window_end_x - window_step_x); x += window_step_x)
         {
-            const auto vbf16_0 = vcombine_bf16(
-                                     vcvt_bf16_f32(vld1q_f32(src_ptr + x)),
-                                     vcvt_bf16_f32(vld1q_f32(src_ptr + x + 4)));
-            vst1q_bf16(dst_ptr + x, vbf16_0);
+            wrapper::vcvt_bf16_f32(reinterpret_cast<float *>(src.ptr()),
+                                   reinterpret_cast<uint16_t *>(dst.ptr()));
+            wrapper::vcvt_bf16_f32(reinterpret_cast<float *>(src.ptr()) + 8,
+                                   reinterpret_cast<uint16_t *>(dst.ptr()) + 8);
         }
+
         for(; x < window_end_x; ++x)
         {
-            *(reinterpret_cast<bfloat16 *>(dst.ptr()) + x) = *(src_ptr + x);
+            *(dst_ptr + x) = *(src_ptr + x);
         }
     },
     src, dst);
@@ -77,9 +81,9 @@ void neon_bfloat16_to_fp32_cast(const ITensor *_src, ITensor *_dst, const Thread
     ARM_COMPUTE_UNUSED(info);
     ARM_COMPUTE_UNUSED(_policy);
 
-    const auto    window_start_x = static_cast<int>(window.x().start());
-    const auto    window_end_x   = static_cast<int>(window.x().end());
-    constexpr int window_step_x  = 8;
+    const auto window_start_x = static_cast<int>(window.x().start());
+    const auto window_end_x   = static_cast<int>(window.x().end());
+    const int  window_step_x  = 16;
 
     ARM_COMPUTE_ERROR_ON_NULLPTR(_src, _dst);
     ARM_COMPUTE_ERROR_ON(_src == _dst);
@@ -91,26 +95,48 @@ void neon_bfloat16_to_fp32_cast(const ITensor *_src, ITensor *_dst, const Thread
 
     Iterator src(_src, win);
     Iterator dst(_dst, win);
-    /* Up-conversion BFLOAT16 -> F32 */
-    execute_window_loop(win, [&](const Coordinates &)
+    switch(_dst->info()->data_type())
     {
-        const auto src_ptr = reinterpret_cast<const bfloat16_t *>(src.ptr());
-        const auto dst_ptr = reinterpret_cast<float *>(dst.ptr());
-
-        int       x = window_start_x;
-        const int right_bound(window_end_x - window_step_x);
-        for(; x <= right_bound; x += window_step_x)
+        case DataType::F32:
         {
-            const bfloat16x8_t vinput = vld1q_bf16(src_ptr + x);
-            vst1q_f32(dst_ptr + x, vcvt_f32_bf16(vget_low_bf16(vinput)));
-            vst1q_f32(dst_ptr + x + 4, vcvt_f32_bf16(vget_high_bf16(vinput)));
+            /* Up-conversion BFLOAT16 -> F32 */
+            execute_window_loop(win, [&](const Coordinates &)
+            {
+                const auto src_ptr = reinterpret_cast<const bfloat16 *>(src.ptr());
+                const auto dst_ptr = reinterpret_cast<float *>(dst.ptr());
+
+                int x = window_start_x;
+                for(; x <= (window_end_x - window_step_x); x += window_step_x)
+                {
+                    const uint16x8x2_t texels =
+                    {
+                        {
+                            vld1q_u16(reinterpret_cast<uint16_t *>(src.ptr())),
+                            vld1q_u16(reinterpret_cast<uint16_t *>(src.ptr()) + 8)
+                        }
+                    };
+
+                    vst1q_f32(reinterpret_cast<float *>(dst.ptr()),
+                              vreinterpretq_f32_u32(vshlq_n_u32(vmovl_u16(vget_low_u16(texels.val[0])), 16)));
+                    vst1q_f32(reinterpret_cast<float *>(dst.ptr()) + 4,
+                              vreinterpretq_f32_u32(vshlq_n_u32(vmovl_u16(vget_high_u16(texels.val[0])), 16)));
+                    vst1q_f32(reinterpret_cast<float *>(dst.ptr()) + 8,
+                              vreinterpretq_f32_u32(vshlq_n_u32(vmovl_u16(vget_low_u16(texels.val[1])), 16)));
+                    vst1q_f32(reinterpret_cast<float *>(dst.ptr()) + 12,
+                              vreinterpretq_f32_u32(vshlq_n_u32(vmovl_u16(vget_high_u16(texels.val[1])), 16)));
+                }
+
+                for(; x < window_end_x; ++x)
+                {
+                    *(dst_ptr + x) = float(*(src_ptr + x));
+                }
+            },
+            src, dst);
+            break;
         }
-        for(; x < window_end_x; ++x)
-        {
-            *(dst_ptr + x) = float(*(reinterpret_cast<const bfloat16 *>(src_ptr) + x));
-        }
-    },
-    src, dst);
+        default:
+            ARM_COMPUTE_ERROR("dst data type unsupported");
+    }
 }
 
 } // namespace cpu
diff --git a/src/cpu/operators/CpuCast.h b/src/cpu/operators/CpuCast.h
index 5e5f3e0ca6..a8342581cb 100644
--- a/src/cpu/operators/CpuCast.h
+++ b/src/cpu/operators/CpuCast.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Arm Limited.
+ * Copyright (c) 2021, 2023 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -56,6 +56,9 @@ public:
      * @param[in]  src    The source tensor to convert. Data types supported: U8/S8/U16/S16/U32/S32/F16/F32.
      * @param[out] dst    The destination tensor. Data types supported: U8/S8/U16/S16/U32/S32/F16/F32.
      * @param[in]  policy Conversion policy.
+     *
+     * @deprecated Support for BFLOAT16 will be removed in 23.05 release
+     *
      */
     void configure(const ITensorInfo *src, ITensorInfo *dst, ConvertPolicy policy);
     /** Static function to check if given info will lead to a valid configuration