Merge branch 'bugfix/o3_fails' into 'master'

Fix compilation errors when -O3 is used

See merge request idf/esp-idf!2396

components/bt/bluedroid/stack/btm/btm_ble.c

@@ -880,7 +880,7 @@ tBTM_SEC_ACTION btm_ble_determine_security_act(BOOLEAN is_originator, BD_ADDR bd
             auth_req |= BTM_LE_AUTH_REQ_MITM;
     }
 
-    tBTM_BLE_SEC_REQ_ACT ble_sec_act;
+    tBTM_BLE_SEC_REQ_ACT ble_sec_act = BTM_BLE_SEC_REQ_ACT_NONE;
     btm_ble_link_sec_check(bdaddr, auth_req, &ble_sec_act);
 
     BTM_TRACE_DEBUG ("%s ble_sec_act %d", __func__ , ble_sec_act);

components/driver/rtc_module.c

@@ -508,9 +508,10 @@ static void touch_pad_filter_cb(void *arg)
     if (s_touch_pad_filter == NULL) {
         return;
     }
-    uint16_t val;
+    uint16_t val = 0;
     for (int i = 0; i < TOUCH_PAD_MAX; i++) {
-        touch_pad_read(i, &val);
+        (void) touch_pad_read(i, &val);
+        // if touch_pad_read fails then the previous value of val is used
         s_touch_pad_filter->filtered_val[i] = s_touch_pad_filter->filtered_val[i] == 0 ? (val << TOUCH_PAD_SHIFT_DEFAULT) : s_touch_pad_filter->filtered_val[i];
         s_touch_pad_filter->filtered_val[i] = _touch_filter_iir((val << TOUCH_PAD_SHIFT_DEFAULT),
                 s_touch_pad_filter->filtered_val[i], TOUCH_PAD_FILTER_FACTOR_DEFAULT);

components/fatfs/src/vfs_fat.c

@@ -639,6 +639,7 @@ static int vfs_fat_readdir_r(void* ctx, DIR* pdir,
     vfs_fat_dir_t* fat_dir = (vfs_fat_dir_t*) pdir;
     FRESULT res = f_readdir(&fat_dir->ffdir, &fat_dir->filinfo);
     if (res != FR_OK) {
+        *out_dirent = NULL;
         ESP_LOGD(TAG, "%s: fresult=%d", __func__, res);
         return fresult_to_errno(res);
     }

components/sdmmc/sdmmc_cmd.c

@@ -321,7 +321,7 @@ esp_err_t sdmmc_card_init(const sdmmc_host_t* config, sdmmc_card_t* card)
     } else {
         /* IO card */
         if (config->flags & SDMMC_HOST_FLAG_4BIT) {
-            uint8_t card_cap;
+            uint8_t card_cap = 0;
             err = sdmmc_io_rw_direct(card, 0, SD_IO_CCCR_CARD_CAP,
                     SD_ARG_CMD52_READ, &card_cap);
             if (err != ESP_OK) {