OpenCL: Fix a bug in BENCH_CLERROR, it could return -1 during test

Now returns 0 (fail, don't abort) during self-test/benchmark, but
only after printing the error.
Also document the behavior with negative return during autotune.

Author: magnumripper

src/formats.h

@@ -384,7 +384,9 @@ struct fmt_methods {
  * computes other than the requested count (such as if it generates additional
  * candidate passwords on its own).  The updated count is used for c/s rate
  * calculation.  The return value is thus in the 0 to updated *count range.
- * As an exception, a -1 return is used on error during OpenCL auto-tune. */
+ * A special case is that during autotune (only), it may return -1 to signal
+ * to the autotune logic that there was an OpenCL failure, so it can silently
+ * back down. */
 	int (*crypt_all)(int *count, struct db_salt *salt);
 
 /* These functions calculate a hash out of a ciphertext that has just been

src/opencl_common.h

@@ -254,10 +254,12 @@ void opencl_process_event(void);
 					NODE, get_error_name(__err), __FILE__, __LINE__, message); \
 			else if (options.verbosity > VERB_LEGACY) \
 				fprintf(stderr, " %u: %s\n", NODE, get_error_name(__err)); \
-			if (!(ocl_autotune_running || bench_or_test_running)) \
-				error(); \
-			else \
+			if (ocl_autotune_running) \
 				return -1; \
+			else if (bench_or_test_running) \
+				return 0; \
+			else \
+				error(); \
 		} \
 	} while (0)