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From: Shuai Wang <wangshuai901@gmail.com>
Date: Thu, 18 Feb 2021 11:12:30 +0800
Message-ID: <CAEQMQonQk1KpdX+wAVAq-cQH+TnVJrVwwf9=fyR2485CYars_w@mail.gmail.com>
Subject: Re: Performing inter-procedural dataflow analysis
To: GCC Development <gcc@gcc.gnu.org>
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By saying a_2(D) originated from parameter "a", what I mean is that I
obtain the tree pointer of "a" given the tree pointer of a_2(D). Is that
possible? I can somehow image to first get the string name of these
variables and do a clumsy (?) comparison. But that seems not very handy...

Thank you!


On Thu, Feb 18, 2021 at 11:09 AM Shuai Wang <wangshuai901@gmail.com> wrote:

> Hello,
>
> I am doing interprocedural dataflow analysis and countered the following
> issue. Suppose I have an GIMPLE IR code as follows, which is after the
> "simdclone" pass while before my own SIMPLE IPA pass:
>
>
> foo (int a, int b)
> {
>   int c;
>   int d;
>   int D.2425;
>   int _5;
>
>   <bb 2> :
> *  c_4 = a_2(D) + b_3(D);  *
> *  _5 = c_4;*
>   ....
>
> As you can see, while propagating certain dataflow facts among local
> variables are smooth (e.g., from c_4 --> c_4 --> _5), I can hardly
> somehow "link" function parameter "a" (or "b") with its first local usage
> "a_2(D)" or "b_3(D)".
>
> So my question is, when traversing the GIMPLE statements and encounter SSA
> variables like "a_2(D)" or "b_3(D)", how do I know they originate from
> parameter "a" and "b"?
>
> Thank you!
>
> Best,
> Shuai
>
>
>
>