checkasm: vp9dsp: benchmark all sub-IDCTs (but not WHT or ADST).

Signed-off-by: Martin Storsjö <martin@martin.st>

tests/checkasm/vp9dsp.c

@@ -269,14 +269,20 @@ static void check_itxfm(void)
         int n_txtps = tx < TX_32X32 ? N_TXFM_TYPES : 1;
 
         for (txtp = 0; txtp < n_txtps; txtp++) {
-            if (check_func(dsp.itxfm_add[tx][txtp], "vp9_inv_%s_%dx%d_add",
-                           tx == 4 ? "wht_wht" : txtp_types[txtp], sz, sz)) {
-                randomize_buffers();
-                ftx(coef, tx, txtp, sz, BIT_DEPTH);
-
-                for (sub = (txtp == 0) ? 1 : 2; sub <= sz; sub <<= 1) {
+            // skip testing sub-IDCTs for WHT or ADST since they don't
+            // implement it in any of the SIMD functions. If they do,
+            // consider changing this to ensure we have complete test
+            // coverage
+            for (sub = (txtp == 0 && tx < 4) ? 1 : sz; sub <= sz; sub <<= 1) {
+                if (check_func(dsp.itxfm_add[tx][txtp],
+                               "vp9_inv_%s_%dx%d_sub%d_add",
+                               tx == 4 ? "wht_wht" : txtp_types[txtp],
+                               sz, sz, sub)) {
                     int eob;
 
+                    randomize_buffers();
+                    ftx(coef, tx, txtp, sz, BIT_DEPTH);
+
                     if (sub < sz) {
                         eob = copy_subcoefs(subcoef0, coef, tx, txtp,
                                             sz, sub, BIT_DEPTH);
@@ -294,8 +300,9 @@ static void check_itxfm(void)
                         !iszero(subcoef0, sz * sz * SIZEOF_COEF) ||
                         !iszero(subcoef1, sz * sz * SIZEOF_COEF))
                         fail();
+
+                    bench_new(dst, sz * SIZEOF_PIXEL, coef, eob);
                 }
-                bench_new(dst, sz * SIZEOF_PIXEL, coef, sz * sz);
             }
         }
     }