[cfe-dev] HowToGetAnalysisEquation

[David Blaikie]

On Tue, Oct 9, 2012 at 7:16 AM, redder_0210 <redder_0210 at yeah.net> wrote:
> Dear all,
> Considering the following code:
> //////////////////////////////////////////////////////////begin
> int MC(int n){
>     int r,t1,t2;
>     if(n > 100){
>         r = n - 10;
>     }
>     else{
>        t1 = n + 11;
>        t2 = MC(t1);
>        r = MC(t2);
>     }
>     return n;
> }
> /////////////////////////////////////////////////////////end
>
> ///////////////////////////////////////////////////////////////
> Now I have got the CFG for the code:
> B5:
>      Entry block;
> succBlock: B4;
>
> B4:
> !
>       int r,t1,t2;
>       if(n > 100)
> succBlock: B3, B2;
>
> B3:
>      r = n - 10;
> succBlock: B1;
>
> B2:
>     t1 = n + 11;
>     t2 = MC(t1);
>     r = MC(t2);
> succBlock: B2;
>
> B1:
>    return r;
>
> ////////////////////////////////////////////////////////////////
>
> But the CFG doesn't contain the full information for the data flow:  for
> example,
>   In the Block B2, the statement "t1 = n + 11;" could transfer data flow to
> the Entry Block.

How could that transfer occur?

> While the CFG doesn't express the transfer information.
> So, my question is how to get the information for the whole data flow
> information based on the CFG?
>
> Thank! s.
>
>
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