cm: drop s1*s6 cross term (redundant post-mx4) — -1 byte Canterbury tier-2

Author: Overmind

lib/cm/cm.c

@@ -882,7 +882,7 @@ static uint16_t cm_predict(cm_t *cm, uint32_t pos, int bp, float *str, uint16_t
     int mx8_ctx = (cm->match.active?1:0)*256 + wl8_b*32 + bp*4 + cc8;
     float m8 = mixer_mix(&cm->mx8[mx8_ctx], str);
     float s4 = stretch(m4); float s1 = stretch(m1), s8 = stretch(m8); float s6 = stretch(m6); float s3 = stretch(m3); float s7 = stretch(m7);
-    float cross = s1 * s8 * 0.006f + s1 * s6 * 0.004f + s3 * s8 * 0.004f;
+    float cross = s1 * s8 * 0.006f + s3 * s8 * 0.004f;
     float mixed = squash((s1*8 + stretch(m2) + s4*3 + stretch(m5)*2 + stretch(m6)*5 + stretch(m7)*3 + s8*8 + cross) / 30.0f);
 
     uint16_t mp = (uint16_t)(mixed * PROB_MAX);