[Bug target/83387] New: PowerPC64 + Ada + RTEMS: Infinite loops in do_reload()

[sebastian.huber@embedded-brains.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83387

            Bug ID: 83387
           Summary: PowerPC64 + Ada + RTEMS: Infinite loops in do_reload()
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sebastian.huber@embedded-brains.de
  Target Milestone: ---

I added support for the 64-bit PowerPC some months ago using a variant of the
ELFv2 ABI. I don't know which kind of long double support I use on this target.
This is difficult for me to understand how this works on 64-bit PowerPC. This
was no problem up to now since nobody used long double with RTEMS on this
target. I tried to build a GCC with Ada support today for the powerpc-rtems5
target. It ends up in infinite loops while building the Ada run-time multilib
for a 64-bit PowerPC variant. To reproduce the problem you can log in to gcc67:

cd /home/sh/tmp/b-gcc/gcc/ada/rts_me6500_m64_nof_noaltivec

gdb --args /home/sh/tmp/b-gcc/./gcc/gnat1 -gnatwa -quiet -nostdinc -nostdinc
-dumpbase a-coteio.ads -auxbase-strip a-coteio.o -O2 -Wextra -Wall -g
-mcpu=e6500 -msoft-float -gnatpg -mcpu=e6500 -m64 -msoft-float -mno-altivec
-gnatO a-scteio.o a-scteio.ads -o -
...
(gdb) bt
#0  spill_pseudos (set=0x7fffffffdf50) at
/home/sh/tmp/gcc/gcc/lra-eliminations.c:1164
#1  update_reg_eliminate(bitmap_head*) () at
/home/sh/tmp/gcc/gcc/lra-eliminations.c:1288
#2  0x0000000000cfbbb3 in lra_eliminate(bool, bool) () at
/home/sh/tmp/gcc/gcc/lra-eliminations.c:1449
#3  0x0000000000ce35ea in lra(_IO_FILE*) () at /home/sh/tmp/gcc/gcc/lra.c:2493
#4  0x0000000000c9c6a2 in do_reload () at /home/sh/tmp/gcc/gcc/ira.c:5443
#5  (anonymous namespace)::pass_reload::execute(function*) () at
/home/sh/tmp/gcc/gcc/ira.c:5627
#6  0x0000000000d61a1b in execute_one_pass(opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2497
#7  0x0000000000d62255 in execute_pass_list_1(opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2586
#8  0x0000000000d62267 in execute_pass_list_1(opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2587
#9  0x0000000000d62299 in execute_pass_list(function*, opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2597
#10 0x0000000000aabaee in cgraph_node::expand() () at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2139
#11 0x0000000000aaccbc in expand_all_functions () at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2275
#12 symbol_table::compile() [clone .part.75] () at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2623
#13 0x0000000000aaefaa in symbol_table::compile (this=0x7ffff753c000) at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2537
#14 symbol_table::finalize_compilation_unit (this=0x7ffff753c000) at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2716
#15 0x0000000000e1efc3 in compile_file () at /home/sh/tmp/gcc/gcc/toplev.c:480
#16 0x000000000068be0b in do_compile () at /home/sh/tmp/gcc/gcc/toplev.c:2059
#17 toplev::main(int, char**) () at /home/sh/tmp/gcc/gcc/toplev.c:2194
#18 0x000000000068e07b in main (argc=25, argv=0x7fffffffe418) at
/home/sh/tmp/gcc/gcc/main.c:39

gdb --args /home/sh/tmp/b-gcc/./gcc/gnat1 -gnatwa -quiet -nostdinc -nostdinc
-dumpbase a-coteio.ads -auxbase-strip a-coteio.o -O2 -Wextra -Wall -g
-mcpu=e6500 -msoft-float -gnatpg -mcpu=e6500 -m64 -msoft-float -mno-altivec
-gnatO a-coteio.o a-coteio.ads -o -
...
(gdb) bt
#0  process_bb_lives(basic_block_def*, int&, bool) () at
/home/sh/tmp/gcc/gcc/lra-lives.c:726
#1  0x0000000000cff3ea in lra_create_live_ranges_1(bool, bool) () at
/home/sh/tmp/gcc/gcc/lra-lives.c:1316
#2  0x0000000000cffea0 in lra_create_live_ranges(bool, bool) () at
/home/sh/tmp/gcc/gcc/lra-lives.c:1380
#3  0x0000000000ce36fa in lra(_IO_FILE*) () at /home/sh/tmp/gcc/gcc/lra.c:2434
#4  0x0000000000c9c6a2 in do_reload () at /home/sh/tmp/gcc/gcc/ira.c:5443
#5  (anonymous namespace)::pass_reload::execute(function*) () at
/home/sh/tmp/gcc/gcc/ira.c:5627
#6  0x0000000000d61a1b in execute_one_pass(opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2497
#7  0x0000000000d62255 in execute_pass_list_1(opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2586
#8  0x0000000000d62267 in execute_pass_list_1(opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2587
#9  0x0000000000d62299 in execute_pass_list(function*, opt_pass*) () at
/home/sh/tmp/gcc/gcc/passes.c:2597
#10 0x0000000000aabaee in cgraph_node::expand() () at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2139
#11 0x0000000000aaccbc in expand_all_functions () at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2275
#12 symbol_table::compile() [clone .part.75] () at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2623
#13 0x0000000000aaefaa in symbol_table::compile (this=0x7ffff753c000) at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2537
#14 symbol_table::finalize_compilation_unit (this=0x7ffff753c000) at
/home/sh/tmp/gcc/gcc/cgraphunit.c:2716
#15 0x0000000000e1efc3 in compile_file () at /home/sh/tmp/gcc/gcc/toplev.c:480
#16 0x000000000068be0b in do_compile () at /home/sh/tmp/gcc/gcc/toplev.c:2059
#17 toplev::main(int, char**) () at /home/sh/tmp/gcc/gcc/toplev.c:2194
#18 0x000000000068e07b in main (argc=25, argv=0x7fffffffe418) at
/home/sh/tmp/gcc/gcc/main.c:39

Scripts to set it up:

/home/sh/tmp/env.sh
/home/sh/tmp/download.sh
/home/sh/tmp/build.sh