Make bench_internal obey secp256k1_fe_sqrt's contract wrt aliasing.

Bench_internal was previously incorrect but wasn't detected by -DVERIFY until PR bitcoin#551.
sipa · Feb 21, 2019 · b76e45d · b76e45d
1 parent 870a977
commit b76e45d
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/src/bench_internal.c b/src/bench_internal.c
@@ -184,9 +184,11 @@ void bench_field_inverse_var(void* arg) {
 void bench_field_sqrt(void* arg) {
     int i;
     bench_inv *data = (bench_inv*)arg;
+    secp256k1_fe t;
 
     for (i = 0; i < 20000; i++) {
-        secp256k1_fe_sqrt(&data->fe_x, &data->fe_x);
+        t = data->fe_x;
+        secp256k1_fe_sqrt(&data->fe_x, &t);
         secp256k1_fe_add(&data->fe_x, &data->fe_y);
     }
 }