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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/95264] Infinite Loop When Compiling Templated C++ code at
 -O1 and above
Date: Fri, 22 May 2020 09:55:46 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95264

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
clang documentation mentions they support [[gnu::flatten]], whether
implementations match here is of course another question.

I guess for a convoluted cgraph our flatten implementation leaves sth to be
desired - if there's two calls to the same function we inline it fully
twice and have to reap benefits of inlining all calls (recursively) in them
twice rather than producing an optimized body for the flatten inlining
first.  One could envision some early cloning for the purpose of flattening,
pushing down the flattening attribute to the clones that end up being
inlined multiple times.  Not sure how easy that would be - Honza?=