(synth_mult): Don't try to make recursive call if we would be shifting by a negative number.

(synth_mult): Don't try to make recursive call if we would be shifting
by a negative number.
(expand_mult): Don't negate VAL if it is negative.

From-SVN: r3788

gcc/expmed.c

@@ -1920,6 +1920,8 @@ synth_mult (t, cost_limit)
       q = t - 1;
       q = q & -q;
       m = exact_log2 (q);
+      if (m >= 0)
+	{
 	  cost = shiftadd_cost[m];
 	  *alg_in = synth_mult ((t - 1) >> m, cost_limit - cost);
 
@@ -1932,10 +1934,13 @@ synth_mult (t, cost_limit)
 	      best_alg->op[best_alg->ops++] = alg_add_t2_m;
 	      best_alg->cost = cost_limit = cost;
 	    }
+	}
 
       q = t + 1;
       q = q & -q;
       m = exact_log2 (q);
+      if (m >= 0)
+	{
 	  cost = shiftsub_cost[m];
 	  *alg_in = synth_mult ((t + 1) >> m, cost_limit - cost);
 
@@ -1949,6 +1954,7 @@ synth_mult (t, cost_limit)
 	      best_alg->cost = cost_limit = cost;
 	    }
 	}
+    }
 
   /* Now, use the simple method of adding or subtracting at the leftmost
      1-bit.  */
@@ -2064,7 +2070,7 @@ expand_mult (mode, op0, op1, target, unsignedp)
 			    - negate_cost);
 
       if (neg_alg.cost + negate_cost < alg.cost)
-	alg = neg_alg, negate = 1, val = - val;
+	alg = neg_alg, negate = 1;
 
       if (alg.cost < mult_cost)
 	{