https://github.com/EasyCrypt/easycrypt
Revision 3f4a0bd5596888cd8d28b97687d477942187aa5f authored by Pierre-Yves Strub on 11 June 2022, 06:10:21 UTC, committed by Adrien Koutsos on 13 June 2022, 09:22:31 UTC
Loops' epilogs must now be deterministic and loop/calls-free.

This forbids the following unsoundness:

```
require import AllCore DBool.

module E = {
  var i,j : int
  proc foo () = {
    var c;
    i <- 0;
    j <- 0;
    c <- false;
    while (!c) {
      i <- i + 1;
      j <- j + 1;
      c <$ {0,1};
    }
    return i = j;
  }

  proc bar () = {
    var c;
    i <- 0;
    j <- 0;
    c <- false;
    while (!c) {
      i <- i + 1;
      c <$ {0,1};
    }
    c <- false;
    while (!c) {
      j <- j + 1;
      c <$ {0,1};
    }
    return i = j;
  }
}.

equiv bad : E.foo ~ E.bar : true ==> ={res}.
proof.
proc.
fission{1} 4!1 @1,2. by sim.
qed.
```

Fix #210
1 parent b9af81d
Raw File
Tip revision: 3f4a0bd5596888cd8d28b97687d477942187aa5f authored by Pierre-Yves Strub on 11 June 2022, 06:10:21 UTC
In loop fusion/fission, add more constraints on the epilog
Tip revision: 3f4a0bd
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