Target support needed for LTO

[Frederic Riss]

Hi,

I tried to enable LTO on my port, but failed to do so. On a stupid
example, I get:

$ k1-gcc -flto toto.o print.o
lto1: internal compiler error: compressed stream: data error
Please submit a full bug report,
with preprocessed source if appropriate.
See  for instructions.
lto-wrapper: /work1/friss/tools/open64/osprey/targia32_k1/devimage/bin/k1-gcc
returned 1 exit status
collect2: lto-wrapper returned 1 exit status

I debugged a bit and found out that the deflate finds that the
compressed data is invalid. I tried to compile with included zlib,
system zlib, Fedora libelf or self-built libelf, the results are the
same...

Is there anything except defining TARGET_BUILTIN_DECL that targets
need to do to have LTO working? Maybe our linker is somehow mangling
the IR sections. Is there some way to debug those issues?

Thanks,
Fred