fix(mbedtls): prevent vectorization fault in clang O2 optimization

Closes https://github.com/espressif/esp-idf/pull/17582

components/mbedtls/port/esp_ds/esp_rsa_dec_alt.c

@@ -62,6 +62,9 @@ static int esp_ds_rsaes_pkcs1_v15_unpadding(unsigned char *input,
     }
 
     /* Verify padding bytes are non-zero in constant time */
+#if defined(__clang__) && defined(__xtensa__)
+    #pragma clang loop vectorize(disable)
+#endif
     for (size_t i = 2; i < ilen; i++) {
         unsigned char in_padding = (i < pad_count + 2);
         unsigned char is_zero = (input[i] == 0x00);

tools/test_apps/system/clang_build_test/sdkconfig.ci.clang_libclang_rt_perf

@@ -0,0 +1,2 @@
+CONFIG_COMPILER_RT_LIB_CLANGRT=y
+CONFIG_COMPILER_OPTIMIZATION_PERF=y