USDC v3

[alexkroeger]

USDC v3 reduces gas costs for users by replacing blacklist checks on transfer, transferFrom, and approve with a freezeBalance admin function.

Please check out this post on mirror.xyz for more context about these proposed changes.

[phil-ociraptor]

While you're at it, can save 5k more gas on swaps and contract interactions by using infinite approval gas optimization!!

Something like this:

Suggested change

	allowed[from][msg.sender] = allowed[from][msg.sender].sub(value);
	if (allowed[from][msg.sender] != uint(-1)) {
	allowed[from][msg.sender] = allowed[from][msg.sender].sub(value);
	}

Reference

• https://twitter.com/philipliao_/status/1479860204577693700?s=20
• https://github.com/makerdao/dss/blob/master/src/dai.sol#L76

[alexkroeger]

in this moment I am euphoric

[PirosB3]

@phil-ociraptor in your suggestion aren't you missing a ]?

L121 of your suggestion 👇

if (allowed[from][msg.sender] != uint(-1)) {

[phil-ociraptor]

🦅 👀

great catch! updated

[eztierney]

Thanks for the PR, this is really cool. We would really love to reduce gas fees. At this point though I'm not sure we can get rid of the blacklist functionality as-is. Such change will require a broader discussion including legal and regulatory compliance teams.

Packing it into the high bit as you suggested https://twitter.com/alex_kroeger/status/1485756038502510593?s=21 might be more appealing as it preserves the existing functionality and should provide similar gas savings.