https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87107
Bug ID: 87107
Summary: Template instantiation is 50x slower than with clang++
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ufospoke at gmail dot com
Target Milestone: ---
Created attachment 44598
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44598&action=edit
File to reproduce the issue
The new IO extension from GIL (boost 1.68.0) takes a very long time to compile
with g++ 8.2.0 compared to clang++ 5 or 6. Note that this is also true with g++
6 and 7 but not with g++ 5. I also opened an issue at boost::gil:
https://github.com/boostorg/gil/issues/131
I was able to identify which code exactly takes so much time to compile and I
was able to make it independent from any external libraries, in particular from
boost (MPL and GIL). See the attached file
"gcc-is-long-minimum-and-standalone.cpp".
With this particular program, g++ 8.2.0 is 53x longer than clang 6.0 on my
x86_64 linux computer (8.175 s vs 0.152 s).
The command line is:
g++-8.2.0 -o out.o -c -O2 -DNDEBUG -std=c++14
Progs/gcc-is-long-minimum-and-standalone.cpp
clang++ -o out.o -c -O2 -DNDEBUG -std=c++14
Progs/gcc-is-long-minimum-and-standalone.cpp
