Fixes bug swiftshader:73.

Change-Id: I6d36348996d22cf507a4badc3af90ce8d654eb71
Reviewed-on: https://swiftshader-review.googlesource.com/10510Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>