tree f9410e54e46fcbf89c82f30c09917afd76fb8bcb
parent e762378c42b786233ea13affa1cc2ee132ceefaf
author Rémy Oudompheng <remyoudompheng@gmail.com> 1573624402 +0100
committer Robert Griesemer <gri@golang.org> 1573672527 +0000

math/big: fix out-of-bounds panic in divRecursive

The bounds in the last carry branch were wrong as there
is no reason for len(u) >= n+n/2 to always hold true.

We also adjust test to avoid using a remainder of 1
(in which case, the last step of the algorithm computes
(qhatv+1) - qhatv which rarely produces a carry).

Change-Id: I69fbab9c5e19d0db1c087fbfcd5b89352c2d26fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/206839
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>