This pretty much explains why Frieza carried out his genocide on the Saiyan race in the first place. In his last moments, Chilled sent a warning to his family about Saiyans, a warning which would eventually reach Frieza, prompting him to wipe out the entire race before they became a threat. That said, this is probably a non-canon scenario.

I might be remembering it wrong, but I seem to remember the original super saiyan being so powerful he killed himself and half the planet or something like that. If that's the case, I don't see how this CAN be canon.

Bardock and the Original Super Saiyan are definitely not the same person, because the OSS was only able to go super saiyan while in his great-ape form.

The OSS literally went ape-shit and destroyed the Saiyan homeworld. The surviving Saiyans fled to Planet Plant, the planet shown in this movie, and renamed it Planet Vegeta.

I'm guessing that Bardock's battle with Chilled is simply lost in history. All of the baddies that saw him were killed by him, and Chilled never gave a very detailed report to his henchmen on what went down on Planet Plant. He just said "Watch out for those goddamn Saiyans" and then died. And the Plant race probably never communicated with any other Saiyan besides Bardock. Or they were all later killed by the Saiyans. Or they evolved into the Tuffle race and *then* were killed by the Saiyans. Who knows.