Bug swiftshader:13

Change-Id: I03cdbb3e5ea28643eb941e162125da68d183d1c6
Reviewed-on: https://swiftshader-review.googlesource.com/7810Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-on: https://swiftshader-review.googlesource.com/8144Reviewed-by: Alexis Hétu <sugoi@google.com>