Bug swiftshader:15

Change-Id: Id270f2f965a5a7154fa4dc83bd1edcd72cf2ff15
Reviewed-on: https://swiftshader-review.googlesource.com/7770Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-on: https://swiftshader-review.googlesource.com/8139Reviewed-by: Alexis Hétu <sugoi@google.com>