[Interest] building Qt [4.8.7 with gcc 5] and link-time optimisation

Thiago Macieira thiago.macieira at intel.com
Thu Jul 23 19:54:55 CEST 2015

On Thursday 23 July 2015 13:36:05 René J. V. Bertin wrote:
> Concerning my test Qt5 build with LTO:
> How well supported/tested is doing that in out-of-source "shadow build"?

It's the only build I do.

> After using -march=core2 instead of -march=native (and thus avoiding the
> use of SSE4 instructions), I'm running into another issue when I execute
> qmake -config ltcg immediately after running configure:
> qt-everywhere-opensource-src-5.4.2/qtbase/src/network/access/qftp.cpp:42:10:
> fatal error:
>       'qcoreapplication.h' file not found
> #include "qcoreapplication.h"
>          ^
> 1 error generated.

git clean -x -d -f in your sources.
(you may want to back up your *.user files from Creator and restore)

Out of sources only work if the source is perfectly clean. Artifacts in the 
source will unpredictably affect the out-of-source build.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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