Fwd: [PATCH] PR19958 wrong code at -O1 and above on x86_64-linux-gnu (InstCombine)

suyog sarda sardask01 at gmail.com
Thu Jul 10 02:06:35 PDT 2014

Adding Duncan

(Something wrong with phabricator, previous mail didn't include Duncan even
after adding him as reviewer.)

---------- Forwarded message ----------
From: suyog <suyog.sarda at samsung.com>
Date: Thu, Jul 10, 2014 at 1:55 AM
Subject: Re: [PATCH] PR19958 wrong code at -O1 and above on
x86_64-linux-gnu (InstCombine)
To: suyog.sarda at samsung.com, rafael.espindola at gmail.com, nlewycky at google.com,
spatel at rotateright.com
Cc: llvm-commits at cs.uiuc.edu

Hi Duncan,

Thanks for your explanation. I have handled case for 'lshr' separately now
in the patch attached.

I have combined the logic for ashr/lshr as well as exact/non-exact as most
of the logic is same.
Wherever there are special cases, i have handled them separately. I have
added the logic for the
cases which were handled by 'instsimplify' to keep the logical flow as

I have combined the logic, since the 'match' functions are expensive, same
for the log,
and our whole point of calculating difference of log was to avoid expensive
division operation.

Please help in reviewing the patch. Your comments/suggestions are most
welcomed :)



llvm-commits mailing list
llvm-commits at cs.uiuc.edu

With regards,
Suyog Sarda
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