Merge #550: Optimize secp256k1_fe_normalize_weak calls.

9bd89c8 Optimize secp256k1_fe_normalize_weak calls. Move secp256k1_fe_normalize_weak calls out of ECMULT_TABLE_GET_GE and ECMULT_TABLE_GET_GE_STORAGE and into secp256k1_ge_globalz_set_table_gej instead. (Russell O'Connor)

Pull request description:

  Move secp256k1_fe_normalize_weak calls out of ECMULT_TABLE_GET_GE and ECMULT_TABLE_GET_GE_STORAGE and into secp256k1_ge_globalz_set_table_gej instead.

Tree-SHA512: 7bbb1aca8e37a268a26d7061bd1f390db129e697792f1d5ddd10ea34927616edc26ef118b500c3e5e14d1d463196033ef64e4d34b765380325c24835458b7a9b

src/group_impl.h

@@ -175,6 +175,8 @@ static void secp256k1_ge_globalz_set_table_gej(size_t len, secp256k1_ge *r, secp
         /* The z of the final point gives us the "global Z" for the table. */
         r[i].x = a[i].x;
         r[i].y = a[i].y;
+        /* Ensure all y values are in weak normal form for fast negation of points */
+        secp256k1_fe_normalize_weak(&r[i].y);
         *globalz = a[i].z;
         r[i].infinity = 0;
         zs = zr[i];