From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dibyendu Majumdar <mobile@majumdar.org.uk>
Subject: Re: [RFC] sparse SSA construction
Date: Tue, 15 Aug 2017 23:44:16 +0100
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To: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, Christopher Li <sparse@chrisli.org>, Linux-Sparse <linux-sparse@vger.kernel.org>

Hi,

I think it would be good to perform a detailed comparison / assessment
of where the problem lies currently versus the new solution. I get the
impression that the current problem is not well explained or
understood.

Here are two known issues at present. You can see the old linearized
output and the new linearized output - both produced with
simplifications switched off.

C code:
https://github.com/dibyendumajumdar/dmr_c/blob/newssa/tests/bugs/simplifybug.c

Old linearized output:
https://github.com/dibyendumajumdar/dmr_c/blob/newssa/tests/bugs/simplifybug_old.lin

New linearized output:
https://github.com/dibyendumajumdar/dmr_c/blob/newssa/tests/bugs/simplifybug_new.lin


C code:
https://github.com/dibyendumajumdar/dmr_c/blob/newssa/tests/set1/onebit.c

Old linearized output:
https://github.com/dibyendumajumdar/dmr_c/blob/newssa/tests/set1/onebit_old.lin

New linearized output:
https://github.com/dibyendumajumdar/dmr_c/blob/newssa/tests/set1/onebit_new.lin


The two situations where I see problems currently are exemplified
above. In the first case the outputs are clearly different - and here
the issue appears to be how undefined pseudos are handled. In the
second case, the original linear output seems identical to the new
output - so the issue probably lies in the single store shortcut.

Regards
Dibyendu