Remove macro CONFIG_INTER_IST

The changes remove macro CONFIG_INTER_IST
diff --git a/aom/aom_encoder.h b/aom/aom_encoder.h
index c49d54a..c955abe 100644
--- a/aom/aom_encoder.h
+++ b/aom/aom_encoder.h
@@ -362,12 +362,10 @@
    *
    */
   unsigned int enable_ist;
-#if CONFIG_INTER_IST
   /*!\brief enable Inter secondary transform
    *
    */
   unsigned int enable_inter_ist;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   /*!\brief enable Inter data-driven transform
    *
diff --git a/aom_dsp/txfm_common.h b/aom_dsp/txfm_common.h
index 19c08c2..5731e92 100644
--- a/aom_dsp/txfm_common.h
+++ b/aom_dsp/txfm_common.h
@@ -37,9 +37,7 @@
   TX_TYPE sec_tx_type;
   // intra prediction mode used for the current tx block
   PREDICTION_MODE intra_mode;
-#if CONFIG_INTER_IST
   int is_inter;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   int use_ddt;
 #endif  // CONFIG_INTER_DDT
diff --git a/apps/aomenc.c b/apps/aomenc.c
index f3e45c4..09a47d3 100644
--- a/apps/aomenc.c
+++ b/apps/aomenc.c
@@ -453,9 +453,7 @@
   &g_av1_codec_arg_defs.enable_idif,
 #endif  // CONFIG_IDIF
   &g_av1_codec_arg_defs.enable_ist,
-#if CONFIG_INTER_IST
   &g_av1_codec_arg_defs.enable_inter_ist,
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   &g_av1_codec_arg_defs.enable_inter_ddt,
 #endif  // CONFIG_INTER_DDT
@@ -665,9 +663,7 @@
   config->enable_idif = 1;
 #endif  // CONFIG_IDIF
   config->enable_ist = 1;
-#if CONFIG_INTER_IST
   config->enable_inter_ist = 1;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   config->enable_inter_ddt = 1;
 #endif  // CONFIG_INTER_DDT
@@ -1518,10 +1514,8 @@
           encoder_cfg->enable_sdp);
   fprintf(stdout, "                               : IST (%d)\n",
           encoder_cfg->enable_ist);
-#if CONFIG_INTER_IST
   fprintf(stdout, "                               : Inter IST (%d)\n",
           encoder_cfg->enable_inter_ist);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   fprintf(stdout, "                               : Inter DDT (%d)\n",
           encoder_cfg->enable_inter_ddt);
diff --git a/av1/arg_defs.c b/av1/arg_defs.c
index b443dcc..39b19a9 100644
--- a/av1/arg_defs.c
+++ b/av1/arg_defs.c
@@ -431,11 +431,9 @@
   .enable_ist = ARG_DEF(NULL, "enable-ist", 1,
                         "Enable intra secondary transform"
                         "(0: false, 1: true (default))"),
-#if CONFIG_INTER_IST
   .enable_inter_ist = ARG_DEF(NULL, "enable-inter-ist", 1,
                               "Enable inter secondary transform"
                               "(0: false, 1: true (default))"),
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   .enable_inter_ddt = ARG_DEF(NULL, "enable-inter-ddt", 1,
                               "Enable inter data-driven transform"
diff --git a/av1/arg_defs.h b/av1/arg_defs.h
index 55e40ac..f9e0709 100644
--- a/av1/arg_defs.h
+++ b/av1/arg_defs.h
@@ -165,9 +165,7 @@
   arg_def_t enable_idif;
 #endif  // CONFIG_IDIF
   arg_def_t enable_ist;
-#if CONFIG_INTER_IST
   arg_def_t enable_inter_ist;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   arg_def_t enable_inter_ddt;
 #endif  // CONFIG_INTER_DDT
diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index 58dac0b..e29a225 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -137,12 +137,10 @@
   int enable_fsc;   // enable forward skip coding
   int enable_orip;  // enable ORIP
 #if CONFIG_IDIF
-  int enable_idif;  // enable IDIF
-#endif              // CONFIG_IDIF
-  int enable_ist;   // enable intra secondary transform
-#if CONFIG_INTER_IST
+  int enable_idif;       // enable IDIF
+#endif                   // CONFIG_IDIF
+  int enable_ist;        // enable intra secondary transform
   int enable_inter_ist;  // enable inter secondary transform
-#endif                   // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   int enable_inter_ddt;     // enable inter data-driven transform
 #endif                      // CONFIG_INTER_DDT
@@ -475,9 +473,7 @@
   1,    // enable IDIF
 #endif  // CONFIG_IDIF
   1,    // enable intra secondary transform
-#if CONFIG_INTER_IST
   1,    // enable inter secondary transform
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   1,    // enable inter data-driven transform
 #endif  // CONFIG_INTER_DDT
@@ -997,9 +993,7 @@
   cfg->enable_idif = extra_cfg->enable_idif;
 #endif  // CONFIG_IDIF
   cfg->enable_ist = extra_cfg->enable_ist;
-#if CONFIG_INTER_IST
   cfg->enable_inter_ist = extra_cfg->enable_inter_ist;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   cfg->enable_inter_ddt = extra_cfg->enable_inter_ddt;
 #endif  // CONFIG_INTER_DDT
@@ -1120,9 +1114,7 @@
   extra_cfg->enable_idif = cfg->enable_idif;
 #endif  // CONFIG_IDIF
   extra_cfg->enable_ist = cfg->enable_ist;
-#if CONFIG_INTER_IST
   extra_cfg->enable_inter_ist = cfg->enable_inter_ist;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   extra_cfg->enable_inter_ddt = cfg->enable_inter_ddt;
 #endif  // CONFIG_INTER_DDT
@@ -1712,10 +1704,8 @@
   txfm_cfg->disable_ml_transform_speed_features =
       extra_cfg->disable_ml_transform_speed_features;
   txfm_cfg->enable_ist = extra_cfg->enable_ist && !extra_cfg->lossless;
-#if CONFIG_INTER_IST
   txfm_cfg->enable_inter_ist =
       extra_cfg->enable_inter_ist && !extra_cfg->lossless;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   txfm_cfg->enable_inter_ddt =
       extra_cfg->enable_inter_ddt && !extra_cfg->lossless;
@@ -3912,11 +3902,9 @@
   } else if (arg_match_helper(&arg, &g_av1_codec_arg_defs.enable_ist, argv,
                               err_string)) {
     extra_cfg.enable_ist = arg_parse_int_helper(&arg, err_string);
-#if CONFIG_INTER_IST
   } else if (arg_match_helper(&arg, &g_av1_codec_arg_defs.enable_inter_ist,
                               argv, err_string)) {
     extra_cfg.enable_inter_ist = arg_parse_int_helper(&arg, err_string);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   } else if (arg_match_helper(&arg, &g_av1_codec_arg_defs.enable_inter_ddt,
                               argv, err_string)) {
@@ -4425,9 +4413,7 @@
         1,
 #endif      // CONFIG_IDIF
         1,  // IST
-#if CONFIG_INTER_IST
         1,  // inter IST
-#endif      // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
         1,  // inter DDT
 #endif      // CONFIG_INTER_DDT
diff --git a/av1/common/av1_common_int.h b/av1/common/av1_common_int.h
index 3c40465..39c1f90 100644
--- a/av1/common/av1_common_int.h
+++ b/av1/common/av1_common_int.h
@@ -486,10 +486,8 @@
   uint8_t
       enable_idif;  // enables/disables Intra Directional Interpolation Filter
 #endif              // CONFIG_IDIF
-  uint8_t enable_ist;  // enables/disables intra secondary transform
-#if CONFIG_INTER_IST
+  uint8_t enable_ist;        // enables/disables intra secondary transform
   uint8_t enable_inter_ist;  // enables/disables inter secondary transform
-#endif                       // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   uint8_t enable_inter_ddt;  // enables/disables inter data-driven transform
 #endif                       // CONFIG_INTER_DDT
diff --git a/av1/common/blockd.h b/av1/common/blockd.h
index ae65663..0904c52 100644
--- a/av1/common/blockd.h
+++ b/av1/common/blockd.h
@@ -3764,13 +3764,8 @@
 static INLINE int block_signals_sec_tx_type(const MACROBLOCKD *xd,
                                             TX_SIZE tx_size, TX_TYPE tx_type,
                                             int eob) {
-#if CONFIG_INTER_IST
-  int should_return =
-      (is_inter_block(xd->mi[0], xd->tree_type) ? (eob <= 3) : (eob <= 1));
-  if (should_return) return 0;
-#else
-  if (eob <= 1) return 0;
-#endif  // CONFIG_INTER_IST
+  if (is_inter_block(xd->mi[0], xd->tree_type) ? (eob <= 3) : (eob <= 1))
+    return 0;
   const MB_MODE_INFO *mbmi = xd->mi[0];
   PREDICTION_MODE intra_dir;
   if (mbmi->filter_intra_mode_info.use_filter_intra) {
@@ -3791,7 +3786,6 @@
     ist_eob = 0;
   }
   const int is_depth0 = tx_size_is_depth0(tx_size, bs);
-#if CONFIG_INTER_IST
   bool condition = (primary_tx_type == DCT_DCT && width >= 16 && height >= 16);
   bool mode_dependent_condition =
       (is_inter_block(mbmi, xd->tree_type)
@@ -3801,12 +3795,6 @@
   const int code_stx =
       (primary_tx_type == DCT_DCT || primary_tx_type == ADST_ADST) &&
       mode_dependent_condition && is_depth0 && ist_eob;
-#else
-  const int code_stx =
-      (primary_tx_type == DCT_DCT || primary_tx_type == ADST_ADST) &&
-      (intra_dir < PAETH_PRED) &&
-      !(mbmi->filter_intra_mode_info.use_filter_intra) && is_depth0 && ist_eob;
-#endif  // CONFIG_INTER_IST
   return code_stx;
 }
 
diff --git a/av1/common/entropymode.c b/av1/common/entropymode.c
index 85617ed..8c8709a 100644
--- a/av1/common/entropymode.c
+++ b/av1/common/entropymode.c
@@ -7555,7 +7555,6 @@
 
 #if CONFIG_ENTROPY_PARA
 #if CONFIG_IST_ANY_SET
-#if CONFIG_INTER_IST
 static const aom_cdf_prob default_stx_cdf[2][TX_SIZES][CDF_SIZE(STX_TYPES)] = {
   {
       { AOM_CDF4(293, 11683, 25053), 75 },
@@ -7574,13 +7573,6 @@
 };
 #else
 static const aom_cdf_prob default_stx_cdf[TX_SIZES][CDF_SIZE(STX_TYPES)] = {
-  { AOM_CDF4(303, 12789, 26360), 75 }, { AOM_CDF4(1671, 11400, 19958), 30 },
-  { AOM_CDF4(2286, 9675, 16955), 5 },  { AOM_CDF4(3524, 9155, 13661), 0 },
-  { AOM_CDF4(8277, 13215, 16769), 6 },
-};
-#endif  // CONFIG_INTER_IST
-#else
-static const aom_cdf_prob default_stx_cdf[TX_SIZES][CDF_SIZE(STX_TYPES)] = {
   { AOM_CDF4(1542, 11565, 24287), 0 },  { AOM_CDF4(4776, 13664, 21624), 0 },
   { AOM_CDF4(7447, 17278, 24725), 0 },  { AOM_CDF4(5783, 17348, 21203), 0 },
   { AOM_CDF4(17873, 20852, 23831), 1 },
diff --git a/av1/common/entropymode.h b/av1/common/entropymode.h
index 080f9c1..bc693a7 100644
--- a/av1/common/entropymode.h
+++ b/av1/common/entropymode.h
@@ -554,11 +554,7 @@
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
   aom_cdf_prob cfl_sign_cdf[CDF_SIZE(CFL_JOINT_SIGNS)];
   aom_cdf_prob cfl_alpha_cdf[CFL_ALPHA_CONTEXTS][CDF_SIZE(CFL_ALPHABET_SIZE)];
-#if CONFIG_INTER_IST
   aom_cdf_prob stx_cdf[2][TX_SIZES][CDF_SIZE(STX_TYPES)];
-#else
-  aom_cdf_prob stx_cdf[TX_SIZES][CDF_SIZE(STX_TYPES)];
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
 #if CONFIG_INTRA_TX_IST_PARSE
   aom_cdf_prob most_probable_stx_set_cdf[CDF_SIZE(IST_DIR_SIZE)];
diff --git a/av1/common/idct.c b/av1/common/idct.c
index f21169d..6b9a00a 100644
--- a/av1/common/idct.c
+++ b/av1/common/idct.c
@@ -434,7 +434,6 @@
 #endif  // CONFIG_IST_SET_FLAG
   txfm_param->sec_tx_type = 0;
   txfm_param->intra_mode = get_intra_mode(mbmi, plane);
-#if CONFIG_INTER_IST
   txfm_param->is_inter = is_inter_block(xd->mi[0], xd->tree_type);
   const int width = tx_size_wide[tx_size];
   const int height = tx_size_high[tx_size];
@@ -450,17 +449,6 @@
     txfm_param->sec_tx_set = get_secondary_tx_set(tx_type);
 #endif  // CONFIG_IST_SET_FLAG
   }
-#else
-  if ((txfm_param->intra_mode < PAETH_PRED) &&
-      !xd->lossless[mbmi->segment_id] &&
-      !(mbmi->filter_intra_mode_info.use_filter_intra)) {
-    // updated EOB condition
-    txfm_param->sec_tx_type = get_secondary_tx_type(tx_type);
-#if CONFIG_IST_SET_FLAG
-    txfm_param->sec_tx_set = get_secondary_tx_set(tx_type);
-#endif  // CONFIG_IST_SET_FLAG
-  }
-#endif  // CONFIG_INTER_IST
   txfm_param->tx_size = tx_size;
   // EOB needs to adjusted after inverse IST
   if (txfm_param->sec_tx_type) {
@@ -642,13 +630,9 @@
   MB_MODE_INFO *const mbmi = xd->mi[0];
   PREDICTION_MODE intra_mode = get_intra_mode(mbmi, plane);
   const int filter = mbmi->filter_intra_mode_info.use_filter_intra;
-#if CONFIG_INTER_IST
   if (!is_inter_block(xd->mi[0], xd->tree_type))
     assert(((intra_mode >= PAETH_PRED || filter) && txfm_param.sec_tx_type) ==
            0);
-#else
-  assert(((intra_mode >= PAETH_PRED || filter) && txfm_param.sec_tx_type) == 0);
-#endif  // CONFIG_INTER_IST
   (void)intra_mode;
   (void)filter;
 
@@ -723,12 +707,8 @@
                          : 32;
 
   if ((width >= 4 && height >= 4) && stx_type) {
-#if CONFIG_INTER_IST
     const PREDICTION_MODE intra_mode =
         (txfm_param->is_inter ? DC_PRED : txfm_param->intra_mode);
-#else
-    const PREDICTION_MODE intra_mode = txfm_param->intra_mode;
-#endif  // CONFIG_INTER_IST
     PREDICTION_MODE mode = 0, mode_t = 0;
     const int log2width = tx_size_wide_log2[txfm_param->tx_size];
 
diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index ab5317f..10a3bb5 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -6425,9 +6425,7 @@
 #endif  // CONFIG_SAME_REF_COMPOUND
   seq_params->enable_sdp = aom_rb_read_bit(rb);
   seq_params->enable_ist = aom_rb_read_bit(rb);
-#if CONFIG_INTER_IST
   seq_params->enable_inter_ist = aom_rb_read_bit(rb);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   seq_params->enable_inter_ddt = aom_rb_read_bit(rb);
 #endif  // CONFIG_INTER_DDT
diff --git a/av1/decoder/decodemv.c b/av1/decoder/decodemv.c
index c654474..197680a 100644
--- a/av1/decoder/decodemv.c
+++ b/av1/decoder/decodemv.c
@@ -1461,7 +1461,6 @@
 }
 
 // This function reads a 'secondary tx set' from the bitstream
-#if CONFIG_INTER_IST
 static void read_secondary_tx_set(MACROBLOCKD *xd, FRAME_CONTEXT *ec_ctx,
                                   aom_reader *r, MB_MODE_INFO *mbmi,
                                   TX_TYPE *tx_type) {
@@ -1486,28 +1485,6 @@
   if (get_primary_tx_type(*tx_type) == ADST_ADST) stx_set_flag += IST_DIR_SIZE;
   set_secondary_tx_set(tx_type, stx_set_flag);
 }
-#else
-static void read_secondary_tx_set(FRAME_CONTEXT *ec_ctx, aom_reader *r,
-                                  MB_MODE_INFO *mbmi, TX_TYPE *tx_type) {
-  uint8_t intra_mode = get_intra_mode(mbmi, PLANE_TYPE_Y);
-#if CONFIG_INTRA_TX_IST_PARSE
-  const TX_TYPE reordered_stx_set_flag =
-      aom_read_symbol(r, ec_ctx->most_probable_stx_set_cdf, IST_DIR_SIZE,
-                      ACCT_INFO("stx_set_flag"));
-  TX_TYPE stx_set_flag =
-      inv_most_probable_stx_mapping[intra_mode][reordered_stx_set_flag];
-#else
-  uint8_t stx_set_ctx = stx_transpose_mapping[intra_mode];
-  assert(stx_set_ctx < IST_DIR_SIZE);
-  TX_TYPE stx_set_flag =
-      aom_read_symbol(r, ec_ctx->stx_set_cdf[stx_set_ctx], IST_DIR_SIZE,
-                      ACCT_INFO("stx_set_flag"));
-#endif  // CONFIG_INTRA_TX_IST_PARSE
-  assert(stx_set_flag < IST_DIR_SIZE);
-  if (get_primary_tx_type(*tx_type) == ADST_ADST) stx_set_flag += IST_DIR_SIZE;
-  set_secondary_tx_set(tx_type, stx_set_flag);
-}
-#endif  // CONFIG_INTER_IST
 
 void av1_read_sec_tx_type(const AV1_COMMON *const cm, MACROBLOCKD *xd,
                           int blk_row, int blk_col, TX_SIZE tx_size,
@@ -1529,53 +1506,25 @@
       1) {
     FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
     const TX_SIZE square_tx_size = txsize_sqr_map[tx_size];
-#if !CONFIG_INTER_IST
-    if (!inter_block) {
-#endif  // CONFIG_INTER_IST
-      if (block_signals_sec_tx_type(xd, tx_size, *tx_type, *eob)) {
-#if CONFIG_INTER_IST
-        const uint8_t stx_flag =
-            aom_read_symbol(r, ec_ctx->stx_cdf[inter_block][square_tx_size],
-                            STX_TYPES, ACCT_INFO("stx_flag"));
-#else
-      const uint8_t stx_flag = aom_read_symbol(
-          r, ec_ctx->stx_cdf[square_tx_size], STX_TYPES, ACCT_INFO("stx_flag"));
-#endif  // CONFIG_INTER_IST
-        *tx_type |= (stx_flag << PRIMARY_TX_BITS);
-#if CONFIG_IST_SET_FLAG
-#if CONFIG_INTER_IST
-        if (stx_flag > 0) read_secondary_tx_set(xd, ec_ctx, r, mbmi, tx_type);
-#else
-        if (stx_flag > 0) read_secondary_tx_set(ec_ctx, r, mbmi, tx_type);
-#endif  // CONFIG_INTER_IST
-#endif  // CONFIG_IST_SET_FLAG
-      }
-#if !CONFIG_INTER_IST
-    }
-#endif  // CONFIG_INTER_IST
-#if CONFIG_INTER_IST
-  } else {
-#else
-  } else if (!inter_block) {
-#endif  // CONFIG_INTER_IST
-    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
-    const TX_SIZE square_tx_size = txsize_sqr_map[tx_size];
     if (block_signals_sec_tx_type(xd, tx_size, *tx_type, *eob)) {
-#if CONFIG_INTER_IST
       const uint8_t stx_flag =
           aom_read_symbol(r, ec_ctx->stx_cdf[inter_block][square_tx_size],
                           STX_TYPES, ACCT_INFO("stx_flag"));
-#else
-      const uint8_t stx_flag = aom_read_symbol(
-          r, ec_ctx->stx_cdf[square_tx_size], STX_TYPES, ACCT_INFO("stx_flag"));
-#endif  // // CONFIG_INTER_IST
       *tx_type |= (stx_flag << PRIMARY_TX_BITS);
 #if CONFIG_IST_SET_FLAG
-#if CONFIG_INTER_IST
       if (stx_flag > 0) read_secondary_tx_set(xd, ec_ctx, r, mbmi, tx_type);
-#else
-      if (stx_flag > 0) read_secondary_tx_set(ec_ctx, r, mbmi, tx_type);
-#endif  // CONFIG_INTER_IST
+#endif  // CONFIG_IST_SET_FLAG
+    }
+  } else {
+    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+    const TX_SIZE square_tx_size = txsize_sqr_map[tx_size];
+    if (block_signals_sec_tx_type(xd, tx_size, *tx_type, *eob)) {
+      const uint8_t stx_flag =
+          aom_read_symbol(r, ec_ctx->stx_cdf[inter_block][square_tx_size],
+                          STX_TYPES, ACCT_INFO("stx_flag"));
+      *tx_type |= (stx_flag << PRIMARY_TX_BITS);
+#if CONFIG_IST_SET_FLAG
+      if (stx_flag > 0) read_secondary_tx_set(xd, ec_ctx, r, mbmi, tx_type);
 #endif  // CONFIG_IST_SET_FLAG
     }
   }
diff --git a/av1/decoder/decodetxb.c b/av1/decoder/decodetxb.c
index 0bee53b..59f96a7 100644
--- a/av1/decoder/decodetxb.c
+++ b/av1/decoder/decodetxb.c
@@ -904,14 +904,10 @@
 
   // read  sec_tx_type here
   // Only y plane's sec_tx_type is transmitted
-#if CONFIG_INTER_IST
   if ((plane == AOM_PLANE_Y) &&
       (is_inter_block(mbmi, xd->tree_type)
            ? (*eob > 3 && cm->seq_params.enable_inter_ist)
            : (*eob != 1 && cm->seq_params.enable_ist))) {
-#else
-  if ((plane == AOM_PLANE_Y) && (cm->seq_params.enable_ist) && (*eob != 1)) {
-#endif  // // CONFIG_INTER_IST
     av1_read_sec_tx_type(cm, xd, blk_row, blk_col, tx_size, eob, r);
   }
   //
@@ -1333,10 +1329,8 @@
   av1_set_entropy_contexts(xd, pd, plane, plane_bsize, tx_size, cul_level, col,
                            row);
   if (is_inter_block(mbmi, xd->tree_type)) {
-#if CONFIG_INTER_IST
-    const TX_TYPE tx_type1 = av1_get_tx_type(xd, plane_type, row, col, tx_size,
-                                             cm->features.reduced_tx_set_used);
-#endif  // CONFIG_INTER_IST
+    const TX_TYPE tx_type_inter = av1_get_tx_type(
+        xd, plane_type, row, col, tx_size, cm->features.reduced_tx_set_used);
     if (plane == 0) {
       const int txw = tx_size_wide_unit[tx_size];
       const int txh = tx_size_high_unit[tx_size];
@@ -1345,11 +1339,7 @@
       const int stride = xd->tx_type_map_stride;
       for (int idy = 0; idy < txh; idy += tx_unit) {
         for (int idx = 0; idx < txw; idx += tx_unit) {
-#if CONFIG_INTER_IST
-          xd->tx_type_map[(row + idy) * stride + col + idx] = tx_type1;
-#else
-          xd->tx_type_map[(row + idy) * stride + col + idx] = tx_type;
-#endif  // CONFIG_INTER_IST
+          xd->tx_type_map[(row + idy) * stride + col + idx] = tx_type_inter;
         }
       }
     }
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 137215a..9e37d38 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -1554,17 +1554,10 @@
 #if CONFIG_TX_TYPE_FLEX_IMPROVE
       if (tx_set_type != EXT_TX_SET_LONG_SIDE_64 &&
           tx_set_type != EXT_TX_SET_LONG_SIDE_32) {
-#if CONFIG_INTER_IST
         aom_write_symbol(
             w, av1_ext_tx_ind[tx_set_type][get_primary_tx_type(tx_type)],
             ec_ctx->inter_ext_tx_cdf[eset][eob_tx_ctx][square_tx_size],
             av1_num_ext_tx_set[tx_set_type]);
-#else
-        aom_write_symbol(
-            w, av1_ext_tx_ind[tx_set_type][tx_type],
-            ec_ctx->inter_ext_tx_cdf[eset][eob_tx_ctx][square_tx_size],
-            av1_num_ext_tx_set[tx_set_type]);
-#endif  // CONFIG_INTER_IST
       } else {
         bool is_long_side_dct =
             is_dct_type(tx_size, get_primary_tx_type(tx_type));
@@ -1582,17 +1575,10 @@
             ec_ctx->inter_ext_tx_short_side_cdf[eob_tx_ctx][square_tx_size], 4);
       }
 #else
-#if CONFIG_INTER_IST
       aom_write_symbol(
           w, av1_ext_tx_ind[tx_set_type][get_primary_tx_type(tx_type)],
           ec_ctx->inter_ext_tx_cdf[eset][eob_tx_ctx][square_tx_size],
           av1_num_ext_tx_set[tx_set_type]);
-#else
-      aom_write_symbol(
-          w, av1_ext_tx_ind[tx_set_type][tx_type],
-          ec_ctx->inter_ext_tx_cdf[eset][eob_tx_ctx][square_tx_size],
-          av1_num_ext_tx_set[tx_set_type]);
-#endif  // CONFIG_INTER_IST
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
     } else {
       if (mbmi->fsc_mode[xd->tree_type == CHROMA_PART]) {
@@ -1706,52 +1692,25 @@
       !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP)) {
     FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
     const TX_SIZE square_tx_size = txsize_sqr_map[tx_size];
-#if !CONFIG_INTER_IST
-    if (!is_inter) {
-#endif  // CONFIG_INTER_IST
-      const TX_TYPE stx_flag = get_secondary_tx_type(tx_type);
-      assert(stx_flag <= STX_TYPES - 1);
-      if (block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
-#if CONFIG_INTER_IST
-        aom_write_symbol(w, stx_flag, ec_ctx->stx_cdf[is_inter][square_tx_size],
-                         STX_TYPES);
-#else
-      aom_write_symbol(w, stx_flag, ec_ctx->stx_cdf[square_tx_size], STX_TYPES);
-#endif  // CONFIG_INTER_IST
+    const TX_TYPE stx_flag = get_secondary_tx_type(tx_type);
+    assert(stx_flag <= STX_TYPES - 1);
+    if (block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
+      aom_write_symbol(w, stx_flag, ec_ctx->stx_cdf[is_inter][square_tx_size],
+                       STX_TYPES);
 #if CONFIG_IST_SET_FLAG
-#if CONFIG_INTER_IST
-        if (stx_flag > 0 && !is_inter)
-          write_sec_tx_set(ec_ctx, w, mbmi, tx_type);
-#else
-        if (stx_flag > 0) write_sec_tx_set(ec_ctx, w, mbmi, tx_type);
-#endif  // CONFIG_INTER_IST
+      if (stx_flag > 0 && !is_inter) write_sec_tx_set(ec_ctx, w, mbmi, tx_type);
 #endif  // CONFIG_IST_SET_FLAG
-      }
-#if !CONFIG_INTER_IST
     }
-#endif  // CONFIG_INTER_IST
-#if CONFIG_INTER_IST
   } else if (!xd->lossless[mbmi->segment_id]) {
-#else
-  } else if (!is_inter && !xd->lossless[mbmi->segment_id]) {
-#endif  // CONFIG_INTER_IST
     FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
     const TX_SIZE square_tx_size = txsize_sqr_map[tx_size];
     TX_TYPE stx_flag = get_secondary_tx_type(tx_type);
     assert(stx_flag <= STX_TYPES - 1);
     if (block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
-#if CONFIG_INTER_IST
       aom_write_symbol(w, stx_flag, ec_ctx->stx_cdf[is_inter][square_tx_size],
                        STX_TYPES);
-#else
-      aom_write_symbol(w, stx_flag, ec_ctx->stx_cdf[square_tx_size], STX_TYPES);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
-#if CONFIG_INTER_IST
       if (stx_flag > 0 && !is_inter) write_sec_tx_set(ec_ctx, w, mbmi, tx_type);
-#else
-      if (stx_flag > 0) write_sec_tx_set(ec_ctx, w, mbmi, tx_type);
-#endif  // CONFIG_INTER_IST
 #endif  // CONFIG_IST_SET_FLAG
     }
   }
@@ -5522,9 +5481,7 @@
 #endif  // CONFIG_SAME_REF_COMPOUND
   aom_wb_write_bit(wb, seq_params->enable_sdp);
   aom_wb_write_bit(wb, seq_params->enable_ist);
-#if CONFIG_INTER_IST
   aom_wb_write_bit(wb, seq_params->enable_inter_ist);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   aom_wb_write_bit(wb, seq_params->enable_inter_ddt);
 #endif  // CONFIG_INTER_DDT
diff --git a/av1/encoder/block.h b/av1/encoder/block.h
index 643b4b3..4794537 100644
--- a/av1/encoder/block.h
+++ b/av1/encoder/block.h
@@ -927,11 +927,7 @@
 #endif  // CONFIG_AIMC
 
   //! Cost of signaling secondary transform index
-#if CONFIG_INTER_IST
   int stx_flag_cost[2][TX_SIZES][STX_TYPES];
-#else
-  int stx_flag_cost[TX_SIZES][STX_TYPES];
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
   //! Cost of signaling secondary transform set index
 #if CONFIG_INTRA_TX_IST_PARSE
diff --git a/av1/encoder/encodemb.c b/av1/encoder/encodemb.c
index 374c79c..410e574 100644
--- a/av1/encoder/encodemb.c
+++ b/av1/encoder/encodemb.c
@@ -546,14 +546,9 @@
   const PREDICTION_MODE intra_mode = get_intra_mode(mbmi, plane);
   const int filter = mbmi->filter_intra_mode_info.use_filter_intra;
   const int is_depth0 = tx_size_is_depth0(txfm_param->tx_size, plane_bsize);
-#if CONFIG_INTER_IST
   if (!is_inter_block(mbmi, xd->tree_type))
     assert(((intra_mode >= PAETH_PRED || filter || !is_depth0) &&
             txfm_param->sec_tx_type) == 0);
-#else
-  assert(((intra_mode >= PAETH_PRED || filter || !is_depth0) &&
-          txfm_param->sec_tx_type) == 0);
-#endif  // CONFIG_INTER_IST
   (void)intra_mode;
   (void)filter;
   (void)is_depth0;
@@ -657,7 +652,6 @@
 #endif  // CONFIG_IST_SET_FLAG
   txfm_param->sec_tx_type = 0;
   txfm_param->intra_mode = get_intra_mode(mbmi, plane);
-#if CONFIG_INTER_IST
   txfm_param->is_inter = is_inter_block(xd->mi[0], xd->tree_type);
   const int width = tx_size_wide[tx_size];
   const int height = tx_size_high[tx_size];
@@ -675,18 +669,6 @@
 #endif  // CONFIG_IST_SET_FLAG
     txfm_param->sec_tx_type = get_secondary_tx_type(tx_type);
   }
-#else
-  if ((txfm_param->intra_mode < PAETH_PRED) &&
-      !xd->lossless[mbmi->segment_id] &&
-      !(mbmi->filter_intra_mode_info.use_filter_intra) &&
-      !(mbmi->fsc_mode[xd->tree_type == CHROMA_PART]) &&
-      cm->seq_params.enable_ist) {
-#if CONFIG_IST_SET_FLAG
-    txfm_param->sec_tx_set = get_secondary_tx_set(tx_type);
-#endif  // CONFIG_IST_SET_FLAG
-    txfm_param->sec_tx_type = get_secondary_tx_type(tx_type);
-  }
-#endif  // CONFIG_INTER_IST
   txfm_param->cctx_type = cctx_type;
 #if CONFIG_INTER_DDT
   txfm_param->use_ddt =
diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index f23580c..b877133 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -453,9 +453,7 @@
   seq->enable_idif = oxcf->intra_mode_cfg.enable_idif;
 #endif  // CONFIG_IDIF
   seq->enable_ist = oxcf->txfm_cfg.enable_ist;
-#if CONFIG_INTER_IST
   seq->enable_inter_ist = oxcf->txfm_cfg.enable_inter_ist;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   seq->enable_inter_ddt = oxcf->txfm_cfg.enable_inter_ddt;
 #endif  // CONFIG_INTER_DDT
diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index b7c3b94..551ce0c 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -338,12 +338,10 @@
    * Flag to indicate if intra secondary transform should be enabled.
    */
   bool enable_ist;
-#if CONFIG_INTER_IST
   /*!
    * Flag to indicate if inter secondary transform should be enabled.
    */
   bool enable_inter_ist;
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   /*!
    * Flag to indicate if inter data-driven transform should be enabled.
@@ -1281,11 +1279,7 @@
   unsigned int delta_lf_multi_cnts[FRAME_LF_COUNT][CDF_SIZE(DELTA_LF_PROBS +
                                                             1)];  // placeholder
   unsigned int delta_lf_cnts[CDF_SIZE(DELTA_LF_PROBS + 1)];       // placeholder
-#if CONFIG_INTER_IST
-  unsigned int stx_cnts[2][TX_SIZES][CDF_SIZE(STX_TYPES)];  // placeholder
-#else
-  unsigned int stx_cnts[TX_SIZES][CDF_SIZE(STX_TYPES)];      // placeholder
-#endif  // CONFIG_INTER_IST
+  unsigned int stx_cnts[2][TX_SIZES][CDF_SIZE(STX_TYPES)];        // placeholder
 #if CONFIG_IST_SET_FLAG
 #if CONFIG_INTRA_TX_IST_PARSE
   unsigned int stx_set_cnts[CDF_SIZE(IST_DIR_SIZE)];  // placeholder
diff --git a/av1/encoder/encodetxb.c b/av1/encoder/encodetxb.c
index f0e3e10..4760b95 100644
--- a/av1/encoder/encodetxb.c
+++ b/av1/encoder/encodetxb.c
@@ -1040,14 +1040,10 @@
 
   // write sec_tx_type here
   // Only y plane's sec_tx_type is transmitted
-#if CONFIG_INTER_IST
   if ((plane == AOM_PLANE_Y) &&
       (is_inter_block(xd->mi[0], xd->tree_type)
            ? (eob > 3 && cm->seq_params.enable_inter_ist)
            : (eob != 1 && cm->seq_params.enable_ist))) {
-#else
-  if ((plane == AOM_PLANE_Y) && (cm->seq_params.enable_ist) && eob != 1) {
-#endif  // CONFIG_INTER_IST
     av1_write_sec_tx_type(cm, xd, tx_type, tx_size, eob, w);
   }
 
@@ -1846,7 +1842,6 @@
         const TxSetType tx_set_type =
             av1_get_ext_tx_set_type(tx_size, is_inter, reduced_tx_set_used);
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
-#if CONFIG_INTER_IST
         int tx_type_cost = 0;
 #if CONFIG_TX_TYPE_FLEX_IMPROVE
         if (tx_set_type != EXT_TX_SET_LONG_SIDE_64 &&
@@ -1885,10 +1880,6 @@
                                          [get_secondary_tx_type(tx_type)];
         }
         return tx_type_cost;
-#else
-        return x->mode_costs.inter_tx_type_costs[ext_tx_set][eob_tx_ctx]
-                                                [square_tx_size][tx_type];
-#endif  // CONFIG_INTER_IST
       }
     } else {
       if (ext_tx_set > 0) {
@@ -1958,15 +1949,9 @@
 
         if (block_signals_sec_tx_type(xd, tx_size, tx_type, eob) &&
             xd->enable_ist) {
-#if CONFIG_INTER_IST
           tx_type_cost +=
               x->mode_costs.stx_flag_cost[is_inter][square_tx_size]
                                          [get_secondary_tx_type(tx_type)];
-#else
-          tx_type_cost +=
-              x->mode_costs.stx_flag_cost[square_tx_size]
-                                         [get_secondary_tx_type(tx_type)];
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
           if (get_secondary_tx_type(tx_type) > 0)
             tx_type_cost += get_sec_tx_set_cost(x, mbmi, tx_type);
@@ -1975,30 +1960,15 @@
         return tx_type_cost;
       }
     }
-#if CONFIG_INTER_IST
   } else if (!xd->lossless[xd->mi[0]->segment_id]) {
-#else
-  } else if (!is_inter && !xd->lossless[xd->mi[0]->segment_id]) {
-#endif  // CONFIG_INTER_IST
     if (block_signals_sec_tx_type(xd, tx_size, tx_type, eob) &&
         xd->enable_ist) {
-#if CONFIG_INTER_IST
       int tx_type_cost =
           x->mode_costs.stx_flag_cost[is_inter][square_tx_size]
                                      [get_secondary_tx_type(tx_type)];
-#else
-      int tx_type_cost =
-          x->mode_costs
-              .stx_flag_cost[square_tx_size][get_secondary_tx_type(tx_type)];
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
-#if CONFIG_INTER_IST
       if (get_secondary_tx_type(tx_type) > 0 && !is_inter)
         tx_type_cost += get_sec_tx_set_cost(x, mbmi, tx_type);
-#else
-    if (get_secondary_tx_type(tx_type) > 0)
-      tx_type_cost += get_sec_tx_set_cost(x, mbmi, tx_type);
-#endif  // CONFIG_INTER_IST
 #endif  // CONFIG_IST_SET_FLAG
       return tx_type_cost;
     }
@@ -5358,7 +5328,6 @@
             tx_set_type != EXT_TX_SET_LONG_SIDE_32) {
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
           if (allow_update_cdf) {
-#if CONFIG_INTER_IST
             update_cdf(
                 fc->inter_ext_tx_cdf[eset][eob_tx_ctx][txsize_sqr_map[tx_size]],
                 av1_ext_tx_ind[tx_set_type][get_primary_tx_type(tx_type)],
@@ -5371,12 +5340,6 @@
                          (int8_t)get_secondary_tx_type(tx_type), STX_TYPES);
             }
 #endif  //! CONFIG_TX_TYPE_FLEX_IMPROVE
-#else
-          update_cdf(
-              fc->inter_ext_tx_cdf[eset][eob_tx_ctx][txsize_sqr_map[tx_size]],
-              av1_ext_tx_ind[tx_set_type][tx_type],
-              av1_num_ext_tx_set[tx_set_type]);
-#endif  // CONFIG_INTER_IST
           }
 #if CONFIG_ENTROPY_STATS
           ++counts->inter_ext_tx[eset][eob_tx_ctx][txsize_sqr_map[tx_size]]
@@ -5410,14 +5373,12 @@
                                            [tx_type_idx];
 #endif  // CONFIG_ENTROPY_STATS
         }
-#if CONFIG_INTER_IST
         // Modified condition for CDF update
         if (allow_update_cdf && cm->seq_params.enable_inter_ist &&
             block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
           update_cdf(fc->stx_cdf[is_inter][txsize_sqr_map[tx_size]],
                      (int8_t)get_secondary_tx_type(tx_type), STX_TYPES);
         }
-#endif
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
       } else {
         if (mbmi->fsc_mode[xd->tree_type == CHROMA_PART] && allow_update_cdf) {
@@ -5505,13 +5466,8 @@
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
             cm->seq_params.enable_ist &&
             block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
-#if CONFIG_INTER_IST
           update_cdf(fc->stx_cdf[is_inter][txsize_sqr_map[tx_size]],
                      (int8_t)get_secondary_tx_type(tx_type), STX_TYPES);
-#else
-            update_cdf(fc->stx_cdf[txsize_sqr_map[tx_size]],
-                       (int8_t)get_secondary_tx_type(tx_type), STX_TYPES);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
           if (get_secondary_tx_type(tx_type) > 0)
             update_sec_tx_set_cdf(fc, mbmi, tx_type);
@@ -5524,7 +5480,6 @@
   }
 }
 // CDF update for txsize_sqr_up_map[tx_size] >= TX_32X32
-#if CONFIG_INTER_IST
 else if (cm->quant_params.base_qindex > 0 &&
          !mbmi->skip_txfm[xd->tree_type == CHROMA_PART] &&
          !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP) &&
@@ -5532,30 +5487,12 @@
                    : cm->seq_params.enable_ist) &&
          block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
   if (eob == 1 && !is_inter && allow_update_cdf) return;
-#else
-    else if (!is_inter && cm->quant_params.base_qindex > 0 &&
-             !mbmi->skip_txfm[xd->tree_type == CHROMA_PART] &&
-             !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP) &&
-             cm->seq_params.enable_ist &&
-             block_signals_sec_tx_type(xd, tx_size, tx_type, eob)) {
-      if (eob == 1 && allow_update_cdf) return;
-#endif  // CONFIG_INTER_IST
   if (allow_update_cdf) {
-#if CONFIG_INTER_IST
     update_cdf(fc->stx_cdf[is_inter][txsize_sqr_map[tx_size]],
                (int8_t)get_secondary_tx_type(tx_type), STX_TYPES);
-#else
-        update_cdf(fc->stx_cdf[txsize_sqr_map[tx_size]],
-                   (int8_t)get_secondary_tx_type(tx_type), STX_TYPES);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IST_SET_FLAG
-#if CONFIG_INTER_IST
     if (get_secondary_tx_type(tx_type) > 0 && !is_inter)
       update_sec_tx_set_cdf(fc, mbmi, tx_type);
-#else
-    if (get_secondary_tx_type(tx_type) > 0)
-      update_sec_tx_set_cdf(fc, mbmi, tx_type);
-#endif  // CONFIG_INTER_IST
 #endif  // CONFIG_IST_SET_FLAG
   }
 }
diff --git a/av1/encoder/hybrid_fwd_txfm.c b/av1/encoder/hybrid_fwd_txfm.c
index 1262e29..4387331 100644
--- a/av1/encoder/hybrid_fwd_txfm.c
+++ b/av1/encoder/hybrid_fwd_txfm.c
@@ -506,12 +506,8 @@
                          : 32;
 
   if ((width >= 4 && height >= 4) && stx_type) {
-#if CONFIG_INTER_IST
     const PREDICTION_MODE intra_mode =
         (txfm_param->is_inter ? DC_PRED : txfm_param->intra_mode);
-#else
-    const PREDICTION_MODE intra_mode = txfm_param->intra_mode;
-#endif  // CONFIG_INTER_IST
     PREDICTION_MODE mode = 0, mode_t = 0;
     const int log2width = tx_size_wide_log2[txfm_param->tx_size];
     const int sb_size = (width >= 8 && height >= 8) ? 8 : 4;
diff --git a/av1/encoder/rd.c b/av1/encoder/rd.c
index 80c4eda..e2e5da4 100644
--- a/av1/encoder/rd.c
+++ b/av1/encoder/rd.c
@@ -535,21 +535,12 @@
                              fc->morph_pred_cdf[i], NULL);
   }
 #endif  // CONFIG_MORPH_PRED
-
-#if CONFIG_INTER_IST
   for (j = 0; j < 2; ++j) {
     for (i = 0; i < TX_SIZES; ++i) {
       av1_cost_tokens_from_cdf(mode_costs->stx_flag_cost[j][i],
                                fc->stx_cdf[j][i], NULL);
     }
   }
-#else
-  for (i = 0; i < TX_SIZES; ++i) {
-    av1_cost_tokens_from_cdf(mode_costs->stx_flag_cost[i], fc->stx_cdf[i],
-                             NULL);
-  }
-#endif  // CONFIG_INTER_IST
-
 #if CONFIG_IST_SET_FLAG
 #if CONFIG_INTRA_TX_IST_PARSE
   av1_cost_tokens_from_cdf(mode_costs->most_probable_stx_set_flag_cost,
diff --git a/av1/encoder/tx_search.c b/av1/encoder/tx_search.c
index 0125ea5..3d35f09 100644
--- a/av1/encoder/tx_search.c
+++ b/av1/encoder/tx_search.c
@@ -2683,13 +2683,9 @@
       // Therefore transform domain distortion is not valid for these
       // transform sizes.
       (txsize_sqr_up_map[tx_size] != TX_64X64) &&
-  // Use pixel domain distortion for IST
-  // TODO(any): Make IST compatible with tx domain distortion
-#if CONFIG_INTER_IST
+      // Use pixel domain distortion for IST
+      // TODO(any): Make IST compatible with tx domain distortion
       !(cm->seq_params.enable_ist || cm->seq_params.enable_inter_ist) &&
-#else
-      !cm->seq_params.enable_ist &&
-#endif  // CONFIG_INTER_IST
       // Use pixel domain distortion for DC only blocks
       !dc_only_blk;
   // Flag to indicate if an extra calculation of distortion in the pixel domain
@@ -2794,13 +2790,9 @@
     }
 #endif  // CONFIG_TX_TYPE_FLEX_IMPROVE
     bool skip_idx = false;
-#if CONFIG_INTER_IST
     xd->enable_ist =
         (is_inter_block(mbmi, xd->tree_type) ? cm->seq_params.enable_inter_ist
                                              : cm->seq_params.enable_ist) &&
-#else
-    xd->enable_ist = cm->seq_params.enable_ist &&
-#endif  // CONFIG_INTER_IST
         !cpi->sf.tx_sf.tx_type_search.skip_stx_search &&
         !mbmi->fsc_mode[xd->tree_type == CHROMA_PART] &&
         !xd->lossless[mbmi->segment_id];
@@ -2808,7 +2800,6 @@
     const PREDICTION_MODE intra_mode = get_intra_mode(mbmi, plane);
     const int filter = mbmi->filter_intra_mode_info.use_filter_intra;
     const int is_depth0 = tx_size_is_depth0(tx_size, plane_bsize);
-#if CONFIG_INTER_IST
     bool skip_stx =
         ((primary_tx_type != DCT_DCT && primary_tx_type != ADST_ADST) ||
          plane != 0 ||
@@ -2816,29 +2807,12 @@
               ? (primary_tx_type == ADST_ADST || txw < 16 || txh < 16)
               : (intra_mode >= PAETH_PRED || filter)) ||
          dc_only_blk || !is_depth0 || (eob_found) || !xd->enable_ist);
-#else
-    bool skip_stx =
-        ((primary_tx_type != DCT_DCT && primary_tx_type != ADST_ADST) ||
-         plane != 0 || is_inter_block(mbmi, xd->tree_type) || dc_only_blk ||
-         intra_mode >= PAETH_PRED || filter || !is_depth0 || (eob_found) ||
-         !xd->enable_ist);
-#endif  // CONFIG_INTER_IST
-
 #if CONFIG_IST_ANY_SET
-#if CONFIG_INTER_IST
     int init_set_id = 0;
     int max_set_id =
         (skip_stx || is_inter_block(mbmi, xd->tree_type)) ? 1 : IST_DIR_SIZE;
-#else
-    int max_set_id = skip_stx ? 1 : IST_DIR_SIZE;
-#endif  // CONFIG_INTER_IST
-
     // Iterate through all possible secondary tx sets for given primary tx type
-#if CONFIG_INTER_IST
     for (int set_id = init_set_id; set_id < max_set_id; ++set_id) {
-#else
-    for (int set_id = 0; set_id < max_set_id; ++set_id) {
-#endif  // CONFIG_INTER_IST
 #endif  // CONFIG_IST_ANY_SET
 
       const int max_stx = xd->enable_ist && !(eob_found) ? 4 : 1;
@@ -2923,7 +2897,6 @@
 
         // pre-skip DC only case to make things faster
         uint16_t *const eob = &p->eobs[block];
-#if CONFIG_INTER_IST
         if (*eob == 1 && plane == PLANE_TYPE_Y && !is_inter) {
           if (tx_type1 == DCT_DCT) eob_found = 1;
           if (tx_type1 != DCT_DCT || (stx && primary_tx_type)) {
@@ -2935,15 +2908,6 @@
           update_txk_array(xd, blk_row, blk_col, tx_size, primary_tx_type);
           continue;
         }
-#else
-      if (*eob == 1 && plane == PLANE_TYPE_Y && !is_inter) {
-        if (tx_type1 == DCT_DCT) eob_found = 1;
-        if (tx_type1 != DCT_DCT || (stx && primary_tx_type)) {
-          update_txk_array(xd, blk_row, blk_col, tx_size, DCT_DCT);
-          continue;
-        }
-      }
-#endif  // CONFIG_INTER_IST
 #if CONFIG_IMPROVEIDTX_RDPH
         if (fsc_mode_in && quant_param.use_optimize_b) {
           av1_optimize_fsc(cpi, x, plane, block, tx_size, tx_type, txb_ctx,
@@ -2971,7 +2935,6 @@
               cost_coeffs(cm, x, plane, block, tx_size, tx_type, CCTX_NONE,
                           txb_ctx, cm->features.reduced_tx_set_used);
         }
-#if CONFIG_INTER_IST
         if (*eob == 1 && plane == PLANE_TYPE_Y && !is_inter) {
           if (tx_type1 == DCT_DCT) eob_found = 1;
           if (tx_type1 != DCT_DCT || (stx && primary_tx_type)) {
@@ -2985,19 +2948,6 @@
           update_txk_array(xd, blk_row, blk_col, tx_size, primary_tx_type);
           continue;
         }
-#else
-      if (*eob == 1 && plane == PLANE_TYPE_Y && !is_inter) {
-        // post quant-skip DC only case
-        if (tx_type1 == DCT_DCT) eob_found = 1;
-        if (tx_type1 != DCT_DCT || (stx && primary_tx_type)) {
-          if (plane == 0)
-            update_txk_array(xd, blk_row, blk_col, tx_size, DCT_DCT);
-          continue;
-        }
-        if (get_secondary_tx_type(tx_type) > 0) continue;
-        if (txfm_param.sec_tx_type > 0) continue;
-      }
-#endif  // CONFIG_INTER_IST
         // If rd cost based on coeff rate alone is already more than best_rd,
         // terminate early.
         if (RDCOST(x->rdmult, rate_cost, 0) > best_rd) continue;
@@ -3128,9 +3078,7 @@
         }
       }  // for (int stx = 0;
 #if CONFIG_IST_ANY_SET
-#if CONFIG_INTER_IST
       if (skip_idx) break;
-#endif  // CONFIG_INTER_IST
     }   // for (int stx_set = 0;
 #endif  // CONFIG_IST_ANY_SET
     if (skip_idx) break;
@@ -3665,11 +3613,7 @@
   int64_t best_rd = INT64_MAX;
   TX_PARTITION_TYPE best_tx_partition = TX_PARTITION_INVALID;
   uint8_t best_partition_entropy_ctxs[MAX_TX_PARTITIONS] = { 0 };
-#if CONFIG_INTER_IST
   TX_TYPE best_partition_tx_types[MAX_TX_PARTITIONS] = { 0 };
-#else
-  TX_PARTITION_TYPE best_partition_tx_types[MAX_TX_PARTITIONS] = { 0 };
-#endif  // CONFIG_INTER_IST
   uint8_t full_blk_skip[MAX_TX_PARTITIONS] = { 0 };
 
   const int threshold = cpi->sf.tx_sf.tx_type_search.ml_tx_split_thresh;
@@ -3755,11 +3699,7 @@
     get_tx_partition_sizes(type, max_tx_size, &txb_pos, sub_txs);
     uint8_t this_blk_skip[MAX_TX_PARTITIONS] = { 0 };
     uint8_t partition_entropy_ctxs[MAX_TX_PARTITIONS] = { 0 };
-#if CONFIG_INTER_IST
     TX_TYPE partition_tx_types[MAX_TX_PARTITIONS] = { 0 };
-#else
-    TX_PARTITION_TYPE partition_tx_types[MAX_TX_PARTITIONS] = { 0 };
-#endif  // CONFIG_INTER_IST
     int cur_block = block;
 
     // Compute cost of each tx size in this partition
diff --git a/build/cmake/aom_config_defaults.cmake b/build/cmake/aom_config_defaults.cmake
index 7f68173..9d6e00e 100644
--- a/build/cmake/aom_config_defaults.cmake
+++ b/build/cmake/aom_config_defaults.cmake
@@ -413,7 +413,6 @@
 set_aom_config_var(
   CONFIG_INTRA_TX_IST_PARSE 1
   "Parsing dependency removal for intra tx type and IST set signaling.")
-set_aom_config_var(CONFIG_INTER_IST 1 "Enable IST for inter blocks.")
 set_aom_config_var(CONFIG_COEFF_HR_ADAPTIVE 1
                    "AV2 enable adaptive coding of HR coefficients.")
 set_aom_config_var(CONFIG_IBP_WEIGHT 1 "Reduce IBP weights memory.")
diff --git a/common/args.c b/common/args.c
index 6f5e009..e79b27e 100644
--- a/common/args.c
+++ b/common/args.c
@@ -104,9 +104,7 @@
     GET_PARAMS(enable_idif);
 #endif  // CONFIG_IDIF
     GET_PARAMS(enable_ist);
-#if CONFIG_INTER_IST
     GET_PARAMS(enable_inter_ist);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
     GET_PARAMS(enable_inter_ddt);
 #endif  // CONFIG_INTER_DDT
diff --git a/common/av1_config.c b/common/av1_config.c
index 8f8578c..58d43ce 100644
--- a/common/av1_config.c
+++ b/common/av1_config.c
@@ -252,9 +252,7 @@
 #endif  // CONFIG_OUTPUT_FRAME_BASED_ON_ORDER_HINT
   AV1C_READ_BIT_OR_RETURN_ERROR(enable_sdp);
   AV1C_READ_BIT_OR_RETURN_ERROR(enable_ist);
-#if CONFIG_INTER_IST
   AV1C_READ_BIT_OR_RETURN_ERROR(enable_inter_ist);
-#endif  // CONFIG_INTER_IST
 #if CONFIG_INTER_DDT
   AV1C_READ_BIT_OR_RETURN_ERROR(enable_inter_ddt);
 #endif  // CONFIG_INTER_DDT