hexagon: slight optimization for argosrt output init (#21463)

Author: YardenTal44

ggml/src/ggml-hexagon/htp/argsort-ops.c

@@ -164,6 +164,12 @@ static void quicksort_values_indices_desc(float * values, int32_t * indices, int
     if (i < right) quicksort_values_indices_desc(values, indices, i, right);
 }
 
+// LUT for ramp initialization of argsort output (first 32 members)
+int32_t argosrt_ramp_lut[32] __attribute__((aligned(VLEN))) = {
+    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
+};
+
 static void htp_argsort_f32(unsigned int n, unsigned int i, void * data) {
     struct htp_argsort_context * actx = (struct htp_argsort_context *)data;
     struct htp_ops_context * octx = actx->octx;
@@ -205,8 +211,12 @@ static void htp_argsort_f32(unsigned int n, unsigned int i, void * data) {
     // Padded to 128 bytes.
 
     size_t values_size = hex_round_up(ne00 * sizeof(float), 128);
+    size_t num_vec_ind_values = hmx_ceil_div(ne00, VLEN/(sizeof(int32_t)));
     float * values_buf = (float *) spad;
     int32_t * indices_buf = (int32_t *) (spad + values_size);
+    HVX_Vector * indices_buf_vec = (HVX_Vector *) (spad + values_size);
+    const HVX_Vector ind_init_vec = *(HVX_Vector *)argosrt_ramp_lut;
+    const HVX_Vector ind_diff_vec = Q6_V_vsplat_R(32);
 
     for (uint32_t r = start_row; r < end_row; r++) {
         uint32_t src_offset = r * nb01;
@@ -218,9 +228,11 @@ static void htp_argsort_f32(unsigned int n, unsigned int i, void * data) {
         hex_l2fetch(src_ptr, ne00 * sizeof(float), ne00 * sizeof(float), 1);
         hvx_copy_f32_au((uint8_t*)values_buf, src_ptr, ne00);
 
-        // Initialize indices
-        for (uint32_t j = 0; j < ne00; j++) {
-            indices_buf[j] = j;
+        // Initialize indices - Start with values 0..31, add 32 for additional vec iterations
+        HVX_Vector curr_ind_vec = ind_init_vec;
+        for (uint32_t j_vec = 0; j_vec < num_vec_ind_values; j_vec++) {
+            indices_buf_vec[j_vec] = curr_ind_vec;
+            curr_ind_vec = Q6_Vw_vadd_VwVw(curr_ind_vec, ind_diff_vec);
         }
 
         // Sort values and mirror swaps to indices