[Bug middle-end/68878] New: [6 Regression] 471.omnetpp in SPEC CPU 2006 is miscompiled with LTO

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68878

            Bug ID: 68878
           Summary: [6 Regression] 471.omnetpp in SPEC CPU 2006 is
                    miscompiled with LTO
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
                CC: hubicka at ucw dot cz
  Target Milestone: ---

On x86, r231438 miscompiled 471.omnetpp in SPEC CPU 2006:

g++  -O3 -funroll-loops -ffast-math -fwhole-program -flto=jobserver
-fuse-linker-plugin  -DSPEC_CPU_LP64        EtherAppCli.o EtherAppCli_n.o
EtherAppSrv.o EtherAppSrv_n.o EtherApp_m.o EtherBus.o EtherBus_n.o
EtherCtrl_m.o EtherEncap.o EtherEncap_n.o EtherFrame_m.o EtherHost_n.o
EtherHub.o EtherHub_n.o EtherLLC.o EtherLLC_n.o EtherMAC.o EtherMAC_n.o
EtherSwitch_n.o LargeNet_n.o MACAddress.o MACAddress_m.o MACRelayUnitBase.o
MACRelayUnitNP.o MACRelayUnitNP_n.o MACRelayUnitPP.o MACRelayUnitPP_n.o
MACRelayUnit_n.o Networks_n.o eth-index_n.o utils.o libs/cmdenv/cmdenv.o
libs/cmdenv/enumstr.o libs/cmdenv/heap.o libs/envir/akoutvectormgr.o
libs/envir/args.o libs/envir/cenvir.o libs/envir/cinifile.o
libs/envir/filemgrs.o libs/envir/main.o libs/envir/omnetapp.o
libs/envir/patmatch.o libs/envir/platdep.o libs/envir/seeds.o
libs/envir/slaveapp.o libs/envir/speedmtr.o libs/sim/carray.o
libs/sim/cexception.o libs/sim/cmessage.o libs/sim/cpar.o libs/sim/ctypes.o
libs/sim/task.o libs/sim/cchannel.o libs/sim/cfsm.o libs/sim/cmodule.o
libs/sim/cpsquare.o libs/sim/cvarhist.o libs/sim/util.o libs/sim/ccoroutine.o
libs/sim/cgate.o libs/sim/cmsgheap.o libs/sim/cqueue.o libs/sim/cwatch.o
libs/sim/cdensity.o libs/sim/chead.o libs/sim/cnetmod.o libs/sim/csimul.o
libs/sim/distrib.o libs/sim/cdetect.o libs/sim/chist.o libs/sim/cobject.o
libs/sim/cstat.o libs/sim/errmsg.o libs/sim/cdispstr.o libs/sim/cksplit.o
libs/sim/coutvect.o libs/sim/cstruct.o libs/sim/onstartup.o libs/sim/cenum.o
libs/sim/cllist.o libs/sim/cpacket.o libs/sim/ctopo.o libs/sim/random.o
libs/sim/std/netpack.o libs/spec/spec_qsort.o                     -o omnetpp
...
Running Benchmarks
  Running 471.omnetpp test peak lto default

471.omnetpp: copy 0 non-zero return code (exit code=6, signal=0)

Preparing for Run #1...
Setting up network `largeNet'...

Program received signal SIGSEGV, Segmentation fault.
0x00000000006da660 in ?? ()
(gdb) bt
#0  0x00000000006da660 in ?? ()
#1  0x00007ffff7555092 in _Unwind_ForcedUnwind_Phase2 (exc=0x6db460, 
    context=0x7fffffffd610) at ../../../src-trunk/libgcc/unwind.inc:163
#2  0x00007ffff75554fd in _Unwind_Resume (exc=0x6db460)
    at ../../../src-trunk/libgcc/unwind.inc:232
#3  0x000000000048532d in cSimpleModule::cSimpleModule(char const*, cModule*,
unsigned int) [clone .constprop.235] ()
#4  0x000000000047ef0f in MACRelayUnitNP__create(char const*, cModule*) ()
#5  0x000000000042c5b5 in cModuleType::create(char const*, cModule*, bool) ()
#6  0x0000000000478f77 in EtherSwitch::doBuildInside() ()
#7  0x000000000044076f in cModule::buildInside() ()
#8  0x0000000000407dcf in LargeNet::doBuildInside() ()
#9  0x000000000044076f in cModule::buildInside() ()
#10 0x0000000000451bab in largeNet::setupNetwork() ()
#11 0x000000000044ca90 in cSimulation::setupNetwork(cNetworkType*, int) [clone
.constprop.64] ()
#12 0x00000000004556be in TCmdenvApp::run() ()
#13 0x0000000000405e48 in main ()
(gdb)