tests: benchdnn: softmax: relax threshold for ACL #1819

ACL softmax accumulates in F16, but oneDNN now expects accumulation in
F32, so the tests fail. This commit partially reverts 6727bbe.
Fixes #1819

tests/benchdnn/softmax/softmax.cpp

@@ -1,5 +1,6 @@
 /*******************************************************************************
 * Copyright 2019-2024 Intel Corporation
+* Copyright 2024 Arm Ltd. and affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -230,7 +231,14 @@ void setup_cmp(compare::compare_t &cmp, const prb_t *prb, data_kind_t kind,
     const float trh_coeff_bwd = (prb->dir & FLAG_FWD) ? 1.f : 4.f;
     const float trh_f32 = trh_coeff_log * trh_coeff_bwd * trh_coeff_f32
             * epsilon_dt(trh_dt);
+#if DNNL_AARCH64_USE_ACL
+    // ACL softmax accumulates in F16, but oneDNN now expects accumulation in
+    // F32, this partially reverts 6727bbe8. For more information, see
+    // https://github.com/oneapi-src/oneDNN/issues/1819
+    const float trh = trh_f32;
+#else
     const float trh = is_flt_or_dbl ? trh_f32 : 0.f;
+#endif
     cmp.set_threshold(trh);
 
     // LogSoftMax is unstable enough when there are attributes on top.
@@ -253,12 +261,17 @@ void setup_cmp(compare::compare_t &cmp, const prb_t *prb, data_kind_t kind,
 
     const auto softmax_add_check
             = [&](const compare::compare_t::driver_check_func_args_t &args) {
+#if DNNL_AARCH64_USE_ACL
+                  auto diff_trh = epsilon_dt(args.dt);
+#else
+                  auto diff_trh = epsilon_dt(dnnl_f32);
+#endif
                   // SSE4.1 and OpenCL rdiff tolerance is too high for
                   // certain scenarios.
                   // Additionally, OpenCL expf implementation may return 1e-38f
                   // values for big negative numbers. This is the guard from
                   // such values.
-                  return args.diff < epsilon_dt(dnnl_f32);
+                  return args.diff < diff_trh;
               };
     cmp.set_driver_check_function(softmax_add_check);
 }