Bug swiftshader:15

Change-Id: I065c52711719b12fe55cf0190e735240c008629e
Reviewed-on: https://swiftshader-review.googlesource.com/7712Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-on: https://swiftshader-review.googlesource.com/7390Reviewed-by: Alexis Hétu <sugoi@google.com>