What happened on planets that Thanos had already wiped out 1/2 of life on?

[darklordoftech]

We know that Thanos had already used the Chitauri to wipe out half of all life on many planets.

[Virginiá]

3/4th

He'd been culling planets for a long time before that, so some of those places probably rebounded. Asgard, not quite.

More to the point, when he snapped, it wasn't exactly a well-thought out wish he put into his wish machine. He literally had a giant axe lodged in his torso, probably close to popping out his back. He could have just as easily died before being able to use his magic glove to heal himself or do the snap. So factoring in civilizations he already murderized was probably not in the cards due to circumstances.

[Progressive Pessimist]

Probably option one. They were culled even more. The Infinity Gauntlet makes no exceptions.