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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/94921] Failure to optimize nots with sub into
 single add
Date: Mon, 04 May 2020 08:44:52 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94921

Uro=C5=A1 Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-05-04
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Uro=C5=A1 Bizjak <ubizjak at gmail dot com> ---
(In reply to Marc Glisse from comment #1)
> x + y ?

Correct.

llvm:

        leal    (%rdi,%rsi), %eax
        retq

gcc:

        notl    %edi
        subl    %esi, %edi
        movl    %edi, %eax
        notl    %eax
        ret

Confirmed, looks like a job for a tree combiner.=