Re: Trunk build failure on Itanium

[Janis Johnson <janis187 at us dot ibm dot com>]

Hans Boehm wrote on August 9, 2001:

> I've been getting consistent build failures along the following lines for an
> IA64/Linux build of the trunk:
> 
> /home/hboehm/gcc/gcc-build/gcc/xgcc -B/home/hboehm/gcc/gcc-build/gcc/
> -B/home/hboehm/gcc/usr/ia64-unknown-linux/bin/
> -B/home/hboehm/gcc/usr/ia64-unknown-linux/lib/ -isystem
> /home/hboehm/gcc/usr/ia64-unknown-linux/include -O2   -DIN_GCC    -W -Wall
> -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -isystem ./include
> -fPIC -g1 -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED  -I. -I.
> -I../../gcc/gcc -I../../gcc/gcc/. -I../../gcc/gcc/config
> -I../../gcc/gcc/../include  -DL_fixdfdi -c ../../gcc/gcc/libgcc2.c -o
> libgcc/./_fixdfdi.o
> ../../gcc/gcc/libgcc2.c: In function `__fixdfti':
> ../../gcc/gcc/libgcc2.c:958: Internal compiler error in propagate_one_insn,
> at flow.c:5312
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.
> make[2]: *** [libgcc/./_fixdfdi.o] Error 1
> 
> This occurs for many, but not all, of the functions in libgcc2.c.  The
> compilations works fine without the -O2.  I believe this is a fairly recent
> regression, though I probably hadn't updated my tree on the IA64 machine for
> a month or so.  I updated my tree a second time last night, and the failure
> still occurred then.  The same tree builds on X86.
> 
> Has anyone else seen this?  Any suggestions/insights?

and later that same day he wrote:

> I looked at this (see http://gcc.gnu.org/ml/gcc/2001-08/msg00555.html) a
> little bit more.
> 
> It appears that propagate_one_insn is trying to (erroneously I think) delete
> the instruction that restores ar.pfs before a sibcall.  It correctly notices
> the error because sibcall_epilogue_contains(insn) returns 1 . 
> 
> The preceding call to insn_dead_p returned true because pbi->reg_live failed
> to include ar.pfs, even though it's considered live at the end of the basic
> block.  I would guess that the liveness information for ar.pfs is no longer
> propagated correctly through the sibcall?
> 
> Could someone who knows this code have a look at this, please?

This problem has existed for at least a month.  Andrew Macleod started
discussing possible fixes in gcc-patches and gcc-bugs on July 26, with
feedback from Richard Henderson, but the last mail on the subject was
August 1.  The problem still exists today.

Janis