libgo: Update to weekly.2011-12-22.

[pf3gnuchains/gcc-fork.git] / libgo / go / math / big / nat.go

diff --git a/libgo/go/math/big/nat.go b/libgo/go/math/big/nat.go
index ead1a88..69681ae 100644 (file)
--- a/libgo/go/math/big/nat.go
+++ b/libgo/go/math/big/nat.go
@@ -1196,12 +1196,16 @@ func (x nat) powersOfTwoDecompose() (q nat, k int) {
 // random creates a random integer in [0..limit), using the space in z if
 // possible. n is the bit length of limit.
 func (z nat) random(rand *rand.Rand, limit nat, n int) nat {
+       if alias(z, limit) {
+               z = nil // z is an alias for limit - cannot reuse
+       }
+       z = z.make(len(limit))
+
        bitLengthOfMSW := uint(n % _W)
        if bitLengthOfMSW == 0 {
                bitLengthOfMSW = _W
        }
        mask := Word((1 << bitLengthOfMSW) - 1)
-       z = z.make(len(limit))
 
        for {
                for i := range z {