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src/lemmas.k.md: rewrite TIME lemma #63

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src/lemmas.k.md: rewrite TIME lemma #63

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029c270
src/lemmas.k.md: rewrite TIME lemma
asymmetric Apr 13, 2020
613d6f3
src/lemmas.k.md: generalize modulo lemmas
asymmetric Apr 13, 2020
b4ccbd1
src/lemmas.k.md: fix typo in <=Int
asymmetric Apr 13, 2020
417de9f
src/lemmas.k.md: add lemma for chopping TIME
asymmetric Apr 14, 2020
9d41886
src/lemmas.k.md: fix TIME rule
asymmetric Apr 14, 2020
774d84b
src/lemmas.k.md: join related lemmas
asymmetric Apr 14, 2020
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7 changes: 3 additions & 4 deletions src/lemmas.k.md
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Expand Up @@ -64,12 +64,11 @@ rule A -Word B <=Int A => #rangeUInt(256, A -Int B)

### Bitwise Modulo

The solidity optimizer compiles `block.time % 2**32` into `TIME AND maxUInt32` instead of `TIME
MOD pow32`. `K` is then unable to reason about the size of the result and so cannot apply further
simplifications. We therefore rewrite it back to `modInt pow32`.
The solidity optimizer compiles `block.time % 2**32` to `block.time AND maxUInt32`.
This lemma ensures the packed storage rules will apply.

```k
rule (maxUInt32 &Int X) => (X modInt pow32)
rule (maxUInt32 &Int X) <=Int maxUInt32 => true
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```

Repeated application of `modInt pow32` can be simplified as follows. This lets us clean the storage
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