This is the mail archive of the gcc-bugs@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[Bug lto/45810] 40% slowdown when using LTO for a single-file program


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45810

--- Comment #5 from Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch> 2010-09-28 13:58:18 UTC ---
(In reply to comment #4)
> Sure.  As with all performance related bugs this needs analysis and is
> unlikely an "LTO" problem - LTO does not (not-)optimize, optimization
> passes do.

I'm wondering if there is any description on how to do this. For example, how
do I get the assembly of a function and the -fdump-tree-all files from a gold
based linking that goes as:

rm -f test.s test2.s test.o test2.o ;
gfortran -c -flto test.f90 ; 
gfortran -c -flto test2.f90 ;  
gfortran -O3 -march=native -fuse-linker-plugin -fwhopr=2 test.o test2.o

just using -S or -fdump-tree-all doesn't work. 

Is 'objdump -d' the only tool ?


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]