fix: Lack of epsilon aware comparison in NETopKV for Fp32 data type.

Align NETopKV FP32 comparison semantics with the scalar reference

Resolves COMPMID-8829

Change-Id: I995a07e0f38587b69b0ac08ee2c85949704f0e60
Signed-off-by: Pablo Marquez Tello <pablo.tello@arm.com>

Author: morgolock

src/cpu/kernels/topkv/generic/neon/fp32.cpp

@@ -26,6 +26,7 @@
 #include "src/cpu/kernels/topkv/generic/neon/impl.h"
 
 #include <arm_neon.h>
+#include <limits>
 
 namespace arm_compute
 {
@@ -44,21 +45,24 @@ static inline uint32_t reduce_u32x4(uint32x4_t v)
 #endif
 }
 
-// Explicit specialization for float: may use float32x4_t etc (only in this TU)
+// Explicit specialization for float: may use float32x4_t
 template <>
 uint32_t count_gt_block<float>(const float *ptr, float threshold)
 {
     using Tag = wrapper::traits::neon_bitvector_tag_t<float, wrapper::traits::BitWidth::W128>;
 
-    const auto thr_vec = wrapper::vdup_n(threshold, Tag{});
-    const auto v       = wrapper::vloadq(ptr);
-    const auto mask    = wrapper::vcgt(v, thr_vec); // underlying uint32x4_t
+    const auto v = wrapper::vloadq(ptr);
+
+    // epsilon-aware compare: treat a > b only when (a - b) > epsilon
+    const float eps_val      = std::numeric_limits<float>::epsilon();
+    const float thr_with_eps = threshold + eps_val;
+    const auto  thr_eps_vec  = wrapper::vdup_n(thr_with_eps, Tag{});
+    const auto  mask         = wrapper::vcgt(v, thr_eps_vec); // new: v > (threshold + eps)
 
     const uint32x4_t m = mask;
     const uint32x4_t b = vshrq_n_u32(m, 31);
     return reduce_u32x4(b);
 }
-
 } // namespace detail
 
 void topkv_fp32_neon(const ITensor *predictions, const ITensor *targets, ITensor *out, uint32_t k, const Window &win)