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From: "ishikawa at yk dot rim.or.jp" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/94781] version 9.3 g++ compilation time is slower by 20% or
 much more (closer to 50 % sometimes)  in comparison to v7.
Date: Mon, 27 Apr 2020 01:55:13 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94781

--- Comment #1 from ishikawa,chiaki <ishikawa at yk dot rim.or.jp> ---
BTW, UnifiedBindings23.cpp is huge. It is about 28MB and more than 3MB
compressed (by gzip). I can send the compressed file by e-mail to anyone
interested in this issue.

As the name suggests, the source file is a clever concatenation of source f=
iles
to avoid the duplicated processing of include files in each source file by
lumping them together and run the compiler once.

I don't know if there is a time consumer that takes non-linear time of its
input source file size in g++, but there may be...
OTOH, the "phase last asm" elapsed time may explain the most of the elapsed
time slow down, and so it should be the first target of investigation.=