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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
Date: Mon, 24 Feb 2014 09:20:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Zhendong Su from comment #3)
> (In reply to Richard Biener from comment #1)
> > Hmm, I can't reproduce this with 4.8 or trunk but with 4.5, 4.6 and 4.7.
> 
> Richard, it still fails for me. Did you use LTO?  

Yes, I did.  For me -O[s23] -flto -v -save-temps -fdump-tree-all results
in a ccXYZ.ltrans0.o.169t.optimized file like


;; Function main (main, funcdef_no=2, decl_uid=2401, symbol_order=0) (executed
once)

main ()
{
  <bb 2>:
  return 0;

}

> $ gcc-trunk -v
> Using built-in specs.
> COLLECT_GCC=gcc-trunk
> COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-
> gnu/4.9.0/lto-wrapper
> Target: x86_64-unknown-linux-gnu
> Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
> --enable-languages=c,c++ --disable-werror --enable-multilib
> Thread model: posix
> gcc version 4.9.0 20140223 (experimental) [trunk revision 208062] (GCC) 
> $   
> $ gcc-trunk -O0 -c foo.c
> $ gcc-trunk -O0 -c main.c
> $ gcc-trunk -Os foo.o main.o
> $ a.out
> $ 
> $ gcc-trunk -flto -O0 -c foo.c
> $ gcc-trunk -flto -O0 -c main.c
> $ gcc-trunk -flto -Os foo.o main.o
> $ a.out
> ^C
> $ 
> $ gcc-4.8 -flto -O0 -c foo.c
> $ gcc-4.8 -flto -O0 -c main.c
> $ gcc-4.8 -flto -Os foo.o main.o
> $ a.out
> ^C
> $