6850606: Regression from JDK 1.6.0_12

Summary: The returned result from multiply should be constructed by using valueOf to take care of the INFLATED case.
Reviewed-by: darcy

src/share/classes/java/math/BigDecimal.java

@@ -1101,7 +1101,7 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
             // See "Hacker's Delight" section 2-12 for explanation of
             // the overflow test.
             if ( (((sum ^ xs) & (sum ^ ys))) >= 0L) // not overflowed
-                return new BigDecimal(null, sum, rscale, 0);
+                return BigDecimal.valueOf(sum, rscale);
         }
         if (fst == null)
             fst = BigInteger.valueOf(xs);
@@ -1311,9 +1311,9 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
              * would occur since division is expensive on most CPUs.
              */
             long product = x * y;
-            int prec = this.precision() + multiplicand.precision();
+            long prec = this.precision() + multiplicand.precision();
             if (prec < 19 || (prec < 21 && (y == 0 || product / y == x)))
-                return new BigDecimal(null, product, productScale, 0);
+                return BigDecimal.valueOf(product, productScale);
             return new BigDecimal(BigInteger.valueOf(x).multiply(y), INFLATED,
                                   productScale, 0);
         }
@@ -1584,7 +1584,7 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
             return (preferredScale >= 0 &&
                     preferredScale < ZERO_SCALED_BY.length) ?
                 ZERO_SCALED_BY[preferredScale] :
-                new BigDecimal(null, 0, preferredScale, 1);
+                BigDecimal.valueOf(0, preferredScale);
         else {
             this.inflate();
             divisor.inflate();

test/java/math/BigDecimal/MultiplyTests.java

@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 1234567
+ * @bug 6850606
  * @summary Test BigDecimal.multiply(BigDecimal)
  * @author xlu
  */
@@ -72,6 +72,16 @@ public class MultiplyTests {
                 }
             }
         }
+
+        BigDecimal x = BigDecimal.valueOf(8L, 1);
+        BigDecimal xPower = BigDecimal.valueOf(-1L);
+        try {
+            for (int i = 0; i < 100; i++) {
+                xPower = xPower.multiply(x);
+            }
+        } catch (Exception ex) {
+            failures++;
+        }
         return failures;
     }