[Builtins] Use 'Either' in 'asConstant'

[effectfully]

I should've done that when I replaced the general m by Either in readKnown.

[effectfully]

/benchmark plutus-benchmark:validation

[iohk-devops]

Comparing benchmark results of 'plutus-benchmark:validation' on 'e8edc836d' (base) and 'ffe8d5d4b' (PR)

Script	e8edc83	ffe8d5d	Change
auction_1-1	306.8 μs	296.8 μs	-3.3%
auction_1-2	987.8 μs	969.4 μs	-1.9%
auction_1-3	985.7 μs	965.5 μs	-2.0%
auction_1-4	401.9 μs	389.2 μs	-3.2%
auction_2-1	306.8 μs	298.7 μs	-2.6%
auction_2-2	983.1 μs	966.9 μs	-1.6%
auction_2-3	1.253 ms	1.227 ms	-2.1%
auction_2-4	989.4 μs	961.7 μs	-2.8%
auction_2-5	403.8 μs	388.1 μs	-3.9%
crowdfunding-success-1	363.4 μs	349.7 μs	-3.8%
crowdfunding-success-2	362.6 μs	351.0 μs	-3.2%
crowdfunding-success-3	362.8 μs	351.0 μs	-3.3%
currency-1	392.0 μs	379.5 μs	-3.2%
escrow-redeem_1-1	572.3 μs	557.6 μs	-2.6%
escrow-redeem_1-2	574.2 μs	556.8 μs	-3.0%
escrow-redeem_2-1	668.8 μs	649.2 μs	-2.9%
escrow-redeem_2-2	667.6 μs	653.9 μs	-2.1%
escrow-redeem_2-3	669.5 μs	654.1 μs	-2.3%
escrow-refund-1	266.9 μs	261.5 μs	-2.0%
future-increase-margin-1	391.2 μs	381.7 μs	-2.4%
future-increase-margin-2	867.5 μs	845.8 μs	-2.5%
future-increase-margin-3	866.7 μs	844.8 μs	-2.5%
future-increase-margin-4	791.3 μs	770.2 μs	-2.7%
future-increase-margin-5	1.196 ms	1.169 ms	-2.3%
future-pay-out-1	391.5 μs	379.9 μs	-3.0%
future-pay-out-2	868.3 μs	842.6 μs	-3.0%
future-pay-out-3	867.3 μs	846.2 μs	-2.4%
future-pay-out-4	1.191 ms	1.172 ms	-1.6%
future-settle-early-1	391.8 μs	380.7 μs	-2.8%
future-settle-early-2	869.9 μs	844.4 μs	-2.9%
future-settle-early-3	868.3 μs	843.7 μs	-2.8%
future-settle-early-4	931.7 μs	907.3 μs	-2.6%
game-sm-success_1-1	639.8 μs	626.0 μs	-2.2%
game-sm-success_1-2	344.3 μs	332.1 μs	-3.5%
game-sm-success_1-3	1.023 ms	973.8 μs	-4.8%
game-sm-success_1-4	403.4 μs	385.8 μs	-4.4%
game-sm-success_2-1	639.4 μs	625.7 μs	-2.1%
game-sm-success_2-2	344.8 μs	330.8 μs	-4.1%
game-sm-success_2-3	994.9 μs	970.6 μs	-2.4%
game-sm-success_2-4	401.8 μs	385.0 μs	-4.2%
game-sm-success_2-5	992.6 μs	968.4 μs	-2.4%
game-sm-success_2-6	400.7 μs	383.6 μs	-4.3%
multisig-sm-1	639.6 μs	626.6 μs	-2.0%
multisig-sm-2	625.6 μs	614.6 μs	-1.8%
multisig-sm-3	632.4 μs	622.3 μs	-1.6%
multisig-sm-4	642.8 μs	627.5 μs	-2.4%
multisig-sm-5	874.7 μs	851.5 μs	-2.7%
multisig-sm-6	640.5 μs	629.1 μs	-1.8%
multisig-sm-7	626.3 μs	617.7 μs	-1.4%
multisig-sm-8	634.9 μs	623.6 μs	-1.8%
multisig-sm-9	642.0 μs	632.6 μs	-1.5%
multisig-sm-10	871.3 μs	857.6 μs	-1.6%
ping-pong-1	532.1 μs	520.0 μs	-2.3%
ping-pong-2	532.3 μs	521.0 μs	-2.1%
ping-pong_2-1	334.6 μs	322.1 μs	-3.7%
prism-1	286.8 μs	275.4 μs	-4.0%
prism-2	693.0 μs	672.0 μs	-3.0%
prism-3	599.3 μs	579.8 μs	-3.3%
pubkey-1	243.9 μs	233.7 μs	-4.2%
stablecoin_1-1	1.394 ms	1.366 ms	-2.0%
stablecoin_1-2	334.7 μs	322.2 μs	-3.7%
stablecoin_1-3	1.601 ms	1.570 ms	-1.9%
stablecoin_1-4	357.4 μs	343.2 μs	-4.0%
stablecoin_1-5	2.055 ms	2.020 ms	-1.7%
stablecoin_1-6	443.4 μs	425.5 μs	-4.0%
stablecoin_2-1	1.393 ms	1.365 ms	-2.0%
stablecoin_2-2	335.7 μs	320.8 μs	-4.4%
stablecoin_2-3	1.610 ms	1.570 ms	-2.5%
stablecoin_2-4	357.9 μs	342.3 μs	-4.4%
token-account-1	307.2 μs	298.0 μs	-3.0%
token-account-2	536.3 μs	519.1 μs	-3.2%
uniswap-1	629.0 μs	613.8 μs	-2.4%
uniswap-2	368.3 μs	357.8 μs	-2.9%
uniswap-3	2.637 ms	2.591 ms	-1.7%
uniswap-4	584.2 μs	567.0 μs	-2.9%
uniswap-5	1.848 ms	1.818 ms	-1.6%
uniswap-6	556.2 μs	540.5 μs	-2.8%
vesting-1	549.9 μs	536.0 μs	-2.5%

[effectfully]

This is crazy.

[effectfully]

It does make some sense: asConstant never gets inlined currently and mtl-style is expensive in that case. 2-4% speedup is unexpected though.

Merging without a review, 'cause the change is completely trivial and clearly beneficial.

[michaelpj]

lgtm