[Bug middle-end/65665] New: [5.0 Regression]: g++.dg/torture/pr64378.C -O2 -flto -fno-use-linker-plugin -flto-partition=none

["hp at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65665

            Bug ID: 65665
           Summary: [5.0 Regression]: g++.dg/torture/pr64378.C   -O2 -flto
                    -fno-use-linker-plugin -flto-partition=none
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code, lto
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hp at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
              Host: x86_64-linux-gnu
            Target: cris-elf

This test passed before, but since a revision in the range (221794:221800],
this test fails as follows:

Running /tmp/hpautotest-gcc1/gcc/gcc/testsuite/g++.dg/torture/dg-torture.exp
...
FAIL: g++.dg/torture/pr64378.C   -O2 -flto -fno-use-linker-plugin
-flto-partition=none  (internal compiler error)
FAIL: g++.dg/torture/pr64378.C   -O2 -flto -fno-use-linker-plugin
-flto-partition=none  (test for excess errors)

In g++.log (cutnpasted):
Executing on host:
/tmp/hpautotest-gcc1/cris-elf/gccobj/gcc/testsuite/g++/../../xg++
-B/tmp/hpautotest-gcc1/cris-elf/gcc
obj/gcc/testsuite/g++/../../
/tmp/hpautotest-gcc1/gcc/gcc/testsuite/g++.dg/torture/pr64378.C 
-fno-diagnostics-show-care
t -fdiagnostics-color=never  -nostdinc++
-I/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/include/cris-elf -
I/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/include
-I/tmp/hpautotest-gcc1/gcc/libstdc++-v3/libsupc++ -I
/tmp/hpautotest-gcc1/gcc/libstdc++-v3/include/backward
-I/tmp/hpautotest-gcc1/gcc/libstdc++-v3/testsuite/util -fmessage-
length=0   -O2 -flto -fno-use-linker-plugin -flto-partition=none  -fno-ipa-cp 
-S   -isystem /tmp/hpautotest-gcc1/cris-e
lf/gccobj/cris-elf/./newlib/targ-include -isystem
/tmp/hpautotest-gcc1/gcc/newlib/libc/include   -o pr64378.s    (timeou
t = 300)
/tmp/hpautotest-gcc1/gcc/gcc/testsuite/g++.dg/torture/pr64378.C:24:1: internal
compiler error: Segmentation fault
0xbbbd85 crash_signal
        /tmp/hpautotest-gcc1/gcc/gcc/toplev.c:383
0xf76aee vec<ipa_param_descriptor, va_heap, vl_embed>::operator[](unsigned int)
        /tmp/hpautotest-gcc1/gcc/gcc/vec.h:736
0xf76aee vec<ipa_param_descriptor, va_heap, vl_ptr>::operator[](unsigned int)
        /tmp/hpautotest-gcc1/gcc/gcc/vec.h:1202
0xf76aee ipa_is_param_used
        /tmp/hpautotest-gcc1/gcc/gcc/ipa-prop.h:405
0xf76aee ipa_icf::sem_item_optimizer::update_hash_by_addr_refs()
        /tmp/hpautotest-gcc1/gcc/gcc/ipa-icf.c:2504
0xf76dd5 ipa_icf::sem_item_optimizer::execute()
        /tmp/hpautotest-gcc1/gcc/gcc/ipa-icf.c:2394
0xf77f7e ipa_icf_driver
        /tmp/hpautotest-gcc1/gcc/gcc/ipa-icf.c:3304
0xf77f7e ipa_icf::pass_ipa_icf::execute(function*)
        /tmp/hpautotest-gcc1/gcc/gcc/ipa-icf.c:3351
Please submit a full bug report,

Judging from the actual changes in the revision range and from the backtrace, I
think it's the ipa-icf.c change rather than any of the other changes (e.g. lto
despite the -flto required to trig this), hence the single CC. I'll also bisect
further.