
GCC gOlogy: studying the impact of optimizations on debugging - matt_d
http://www.fsfla.org/~lxoliva/writeups/gOlogy/gOlogy.txt
======
rurban
Does the same description exist for clang? They are up to -O6. I only know
their pass descriptions
[http://llvm.org/docs/Passes.html](http://llvm.org/docs/Passes.html) but
nothing related to the O level and -g

~~~
aaronmdjones
Are you sure they're up to -O6 ?

Doing this in any autoconf-based program:

    
    
        $ ./configure CC="/usr/bin/clang-8" CFLAGS="-Weverything -O6 -flto=full" LDFLAGS="-fuse-ld=/usr/bin/ld.lld-8"
    

... fails (error: C compiler cannot create executables); same for -O5.

-O4 works, but generates this diagnostic:
    
    
        clang: warning: -O4 is equivalent to -O3 [-Wdeprecated]

