Bug swiftshader:15

Change-Id: If9336a87f90269a295fcd3b3bff2fd6899c773e4
Reviewed-on: https://swiftshader-review.googlesource.com/7910Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-on: https://swiftshader-review.googlesource.com/8154Reviewed-by: Alexis Hétu <sugoi@google.com>