ABC: execution of command "..." failed: return code 134.

[adumont]

Hi,

I initially opened the issue in yosys (YosysHQ/yosys#1675), but @eddiehung recommended me to open it here. See his comment here.

Steps to reproduce the issue

git clone https://github.com/adumont/hrm-cpu.git
cd hrm-cpu
git checkout issueABC
cd verilog
make bin

Failing commit is 2b4180c2bf508fead7d1d14def8600957124f50b.

will try to synthesize the design. The step:

yosys -p "synth_ice40 -top top -blif builddir/alhambra/top.blif " \
              -l builddir/alhambra/Echo/top.log -q hrmcpu.v ufifo.v ALU.v MEMORY.v XALU.v LEDS.v RAND.v ram.v mem_wrapper.v REG.v IR.v PROG.v WAIT.v PC.v ControlUnit.v debouncer.v rxuartlite.v txuartlite.v builddir/alhambra/top_wrapper.v top.v

fails with:

ERROR: ABC: execution of command "/home/adumont/toolchain/bin/yosys-abc -s -f /tmp/yosys-abc-eQGZWS/abc.script 2>&1" failed: return code 134.

$ /home/adumont/toolchain/bin/yosys-abc -s -f /tmp/yosys-abc-eQGZWS/abc.script 
ABC command line: "source /tmp/yosys-abc-eQGZWS/abc.script".
+ read_blif /tmp/yosys-abc-eQGZWS/input.blif 
+ read_lut /tmp/yosys-abc-eQGZWS/lutdefs.txt 
+ strash 
+ ifraig 
+ scorr 
Warning: The network is combinational (run "fraig" or "fraig_sweep").
+ dc2 
+ dretime 
+ strash 
+ dch -f 
+ if 
+ mfs2 
+ lutpack -S 1 
yosys-abc: src/opt/lpk/lpkCore.c:549: int Lpk_ResynthesizeNodeNew(Lpk_Man_t *): Assertion `nGain >= 1 - p->pPars->fZeroCost' failed.
Aborted (core dumped)

I've uploaded some stuff from the /tmp/yosys-abc-eQGZWS:

yosys-abc-eQGZWS.zip

My toolchain is updated to latest git version (tool/commit sha):

yosys.ver:9f5613100b360beb60608df1296ee81dc185e56c
arachne-pnr.ver:c40fb2289952f4f120cc10a5a4c82a6fb88442dc
icestorm.ver:0ec00d892a91cc68e45479b46161f649caea2933
iverilog.ver:b1114760fcfba55ee9ca35ba95e2b3ed2b7c7a20
symbiyosys.ver:500b526131f434b9679732fc89515dbed67c8d7d
verilator.ver:0c6c83e2787803d9b7c014ddbc8710f47d0f82f7
yices2.ver:1dcb71c405b5f1d21b363eb33b566068cad2e87d

Previous commit (053c6f1a5f2ab79add807138b24f92de6b3b308c053c6f1a5f2ab79add807138b24f92de6b3b308c) build fine.

Here's the diff in verilog code: adumont/hrm-cpu@2b4180c.

Expected behavior

It should produce the blif file.

Actual behavior

Fails with assertion in ABC.

More info:

Full build log of working commit: (Build 222) https://travis-ci.com/adumont/hrm-cpu/builds/147103961#L1596

Build log of failing commit: (Build 223) https://travis-ci.com/adumont/hrm-cpu/builds/147104799#L1482

Workaruound

I have tried scratchpad -set abc.script +strash;ifraig;scorr;dc2;dretime;strash;dch,-f;if;mfs2 before synth_ice40, as suggested by @eddiehung and it worked.

[eddiehung]

In case it helps, in YosysHQ/yosys#1675 (comment) I mentioned that I managed to minimise the abc.script to:

read_blif input.blif;
strash;
dc2; # Removing this optimisation command results in a different solution that does not trigger the assertion failure
if;
lutpack -S 1;

to get it to fail with the following backtrace on 71f2b40:

(gdb) bt
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007ffff7a03899 in __GI_abort () at abort.c:79
#2  0x00007ffff7a03769 in __assert_fail_base (fmt=0x7ffff7b97fb8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=0xef7d3e "nGain >= 1 - p->pPars->fZeroCost",
    file=0xef7af4 "src/opt/lpk/lpkCore.c", line=549, function=<optimized out>) at assert.c:92
#3  0x00007ffff7a15006 in __GI___assert_fail (assertion=0xef7d3e "nGain >= 1 - p->pPars->fZeroCost", file=0xef7af4 "src/opt/lpk/lpkCore.c", line=549,
    function=0xef7d5f "int Lpk_ResynthesizeNodeNew(Lpk_Man_t *)") at assert.c:101
#4  0x0000000000867605 in Lpk_ResynthesizeNodeNew (p=0x1839320) at src/opt/lpk/lpkCore.c:549
#5  0x0000000000867a7f in Lpk_Resynthesize (pNtk=0x14b1640, pPars=0x7ffffffed520) at src/opt/lpk/lpkCore.c:690
#6  0x0000000000470737 in Abc_CommandLutpack (pAbc=<optimized out>, argc=3, argv=0x1487b80) at src/base/abci/abc.c:4979
#7  0x0000000000582717 in CmdCommandDispatch (pAbc=0x14863e0, pargc=0x7ffffffed5ec, pargv=0x7ffffffed5f0) at src/base/cmd/cmdUtils.c:153
#8  0x000000000057d4d4 in Cmd_CommandExecute (pAbc=0x14863e0, sCommand=<optimized out>) at src/base/cmd/cmdApi.c:210
#9  0x000000000057ac58 in CmdCommandSource (pAbc=0x14863e0, argc=<optimized out>, argv=<optimized out>) at src/base/cmd/cmd.c:719
#10 0x0000000000582717 in CmdCommandDispatch (pAbc=0x14863e0, pargc=0x7fffffff56ec, pargv=0x7fffffff56f0) at src/base/cmd/cmdUtils.c:153
#11 0x000000000057d4d4 in Cmd_CommandExecute (pAbc=0x14863e0, sCommand=<optimized out>) at src/base/cmd/cmdApi.c:210
#12 0x00000000005bf7ff in Abc_RealMain (argc=<optimized out>, argv=<optimized out>) at src/base/main/mainReal.c:330
#13 0x00007ffff7a051e3 in __libc_start_main (main=0x5bc9b0 <main>, argc=3, argv=0x7fffffffe068, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7fffffffe058) at ../csu/libc-start.c:308
#14 0x00000000004053ce in _start ()