Re: [PATCH/RFC] PR target/15130 SH: A tail call optimization

[Kaz Kojima <kkojima at rr dot iij4u dot or dot jp>]

> Joern Rennecke <joern.rennecke@superh.com> wrote:
>> The patch as such look OK, however, as a re-read the code that you are
>> patching, it appears to me that we have a latent bug here, which will
>> be made worse by your patch.
>> We are testing only for the general purpose registers used up by DImode
>> values (or smaller).  This seems to always give you r2.
>> If the function returns a 128 bit value in general purpose registers,
>> e.g. CDImode, TImode, or DCmode (the latter for soft floating point),
>> then r2 is live.
> 
> Sure.  The appended patch is revised one.  Does it looks ok?

Oops.  With that patch

http://gcc.gnu.org/ml/gcc-patches/2004-05/msg00002.html

3.4.0 fails in bootstrapping:

stage2/xgcc -Bstage2/ -B/usr/gnu/sh4-unknown-linux-gnu/bin/ -c   -g -O2 -DIN_GCC   -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -Wold-style-definition     -DHAVE_CONFIG_H -DGENERATOR_FILE    -I. -I. -I../../LOCAL/gcc-3.4.0/gcc -I../../LOCAL/gcc-3.4.0/gcc/. -I../../LOCAL/gcc-3.4.0/gcc/../include  ../../LOCAL/gcc-3.4.0/gcc/gensupport.c -o gensupport.o
../../LOCAL/gcc-3.4.0/gcc/gensupport.c: In function `shift_output_template':
../../LOCAL/gcc-3.4.0/gcc/gensupport.c:678: internal compiler error: Segmentation fault

Removing r0 and r1 from the candidate for the temporary register in
epilogue case fixes this failure.  It seems that there is something
I'm missing.

Regards,
	kaz