[Bug regression/51038] New: [4.7 Regression]: 29_atomics/atomic_flag/clear/1.cc test_and_set/explicit.cc implicit.cc

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51038

             Bug #: 51038
           Summary: [4.7 Regression]: 29_atomics/atomic_flag/clear/1.cc
                    test_and_set/explicit.cc implicit.cc
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: link-failure, wrong-code
          Severity: normal
          Priority: P3
         Component: regression
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hp@gcc.gnu.org
                CC: amacleod@redhat.com
              Host: x86_64-unknown-linux-gnu
            Target: cris-axis-elf


These tests previously passed, now they fail.
Apparently the "cxx-mem-model merge [6 of 9]" (formally a change in the range
181027:181034) exposed or caused these regressions.  Since then they fail as
follows:

Running
/tmp/hpautotest-gcc1/gcc/libstdc++-v3/testsuite/libstdc++-dg/conformance.exp
...
...
FAIL: 29_atomics/atomic_flag/clear/1.cc (test for excess errors)
WARNING: 29_atomics/atomic_flag/clear/1.cc compilation failed to produce
executable
FAIL: 29_atomics/atomic_flag/test_and_set/explicit.cc (test for excess errors)
WARNING: 29_atomics/atomic_flag/test_and_set/explicit.cc compilation failed to
produce executable
FAIL: 29_atomics/atomic_flag/test_and_set/implicit.cc (test for excess errors)


The messages in libstdc++.log are similar, but have changed since the above. At
r181162 they are as follows:

Executing on host: /tmp/hpautotest-gcc1/cris-elf/gccobj/./gcc/g++
-shared-libgcc -B/tmp/hpautotest-gcc1/cris-elf/gccobj/./gcc -nostdinc++
-L/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/src
-L/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/src/.libs
-nostdinc -B/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/newlib/ -isystem
/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/newlib/targ-include -isystem
/tmp/hpautotest-gcc1/gcc/newlib/libc/include
-B/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libgloss/cris
-L/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libgloss/libnosys
-L/tmp/hpautotest-gcc1/gcc/libgloss/cris
-B/tmp/hpautotest-gcc1/cris-elf/pre/cris-elf/bin/
-B/tmp/hpautotest-gcc1/cris-elf/pre/cris-elf/lib/ -isystem
/tmp/hpautotest-gcc1/cris-elf/pre/cris-elf/include -isystem
/tmp/hpautotest-gcc1/cris-elf/pre/cris-elf/sys-include
-B/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./libgloss/cris/
-L/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./libgloss/cris
-L/tmp/hpautotest-gcc1/gcc/libgloss/cris
-B/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./libstdc++-v3/src/.libs -g -O2
-D_GLIBCXX_ASSERT -fmessage-length=0 -ffunction-sections -fdata-sections -g -O2
-g -O2 -DLOCALEDIR="." -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
/tmp/hpautotest-gcc1/gcc/libstdc++-v3/testsuite/29_atomics/atomic_flag/clear/1.cc
  -std=gnu++0x ./libtestc++.a    -isystem
/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./newlib/targ-include -isystem
/tmp/hpautotest-gcc1/gcc/newlib/libc/include
-B/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./libgloss/cris/
-L/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./libgloss/cris
-L/tmp/hpautotest-gcc1/gcc/libgloss/cris 
-B/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./newlib/
-L/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/./newlib -sim3  -lm   -o
./1.exe    (timeout = 600)
/tmp/ccX4JE6W.o: In function `ZNSt11atomic_flag5clearESt12memory_order':
/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/include/bits/atomic_base.h:311:
undefined reference to `std::atomic_thread_fence(std::memory_order)'
/tmp/ccX4JE6W.o: In function
`ZNSt11atomic_flag12test_and_setESt12memory_order':
/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/include/bits/atomic_base.h:274:
undefined reference to `__sync_lock_test_and_set_1'
collect2: error: ld returned 1 exit status
compiler exited with status 1
output is:
/tmp/ccX4JE6W.o: In function `ZNSt11atomic_flag5clearESt12memory_order':
/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/include/bits/atomic_base.h:311:
undefined reference to `std::atomic_thread_fence(std::memory_order)'
/tmp/ccX4JE6W.o: In function
`ZNSt11atomic_flag12test_and_setESt12memory_order':
/tmp/hpautotest-gcc1/cris-elf/gccobj/cris-elf/libstdc++-v3/include/bits/atomic_base.h:274:
undefined reference to `__sync_lock_test_and_set_1'
collect2: error: ld returned 1 exit status

with the 29_atomics/atomic_flag/test_and_set/explicit.cc test only having the
last undefined reference.

Author of the suspect patches in the revision range CC:ed.

cris-elf does not have any back-end atomicity support patterns specified,
there's just the libstdc++-v3/config/cpu/cris atomicity header files,
apparently obsoleted by the cxx-mem-model merge.