Bug swiftshader:121

Change-Id: I8c76a75e25c59ec8f71c5874dd0797202253f215
Reviewed-on: https://swiftshader-review.googlesource.com/c/21948Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>