[Bug target/94278] New: [amdgcn] Offloading build failures due to 'llvm-mc' SIGSEGV

Mon Mar 23 13:45:26 GMT 2020

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94278

            Bug ID: 94278
           Summary: [amdgcn] Offloading build failures due to 'llvm-mc'
                    SIGSEGV
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: openacc, openmp
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: ams at gcc dot gnu.org, jules at gcc dot gnu.org
  Target Milestone: ---

This is with GCC commit b73f69020f08208d2d969fcf8879bd294a6e3596 sources, with
commit b12fb08bd95d7dbb9fd6af120ee0b4c658a3deb1, and commit
65858e1869be4a54f8e0e2073a4aa99b15471273 cherry-picked, and PR94248 fixed with
Jakub's 'reg_overlap_mentioned_p' patch.

Relative to a GCC nvptx offloading configuration, when adding amdgcn
offloading, I see the following regression:

    [-PASS:-]{+FAIL: libgomp.c/../libgomp.c-c++-common/pr93515.c (internal
compiler error)+}
    {+FAIL:+} libgomp.c/../libgomp.c-c++-common/pr93515.c (test for excess
errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/../libgomp.c-c++-common/pr93515.c
[-execution test-]{+compilation failed to produce executable+}

    Stack dump:
    0.      Program arguments:
[...]/install/offload-amdgcn-amdhsa/amdgcn-amdhsa/bin/as -triple=amdgcn--amdhsa
-mattr=-code-object-v3 -mcpu=fiji -filetype=obj -o /tmp/ccn2bzJ1.o
/tmp/cchOR6jK.mkoffload.2.s 
    xgcc: internal compiler error: Segmentation fault signal terminated program
as
    [...]
    mkoffload: fatal error:
[...]/build-gcc/./gcc/x86_64-pc-linux-gnu-accel-amdgcn-amdhsa-gcc returned 4
exit status

That's with stock Ubuntu 18.04 LLVM 9 packages:

    $ [...]/install/offload-amdgcn-amdhsa/amdgcn-amdhsa/bin/as --version
    LLVM (http://llvm.org/):
      LLVM version 9.0.0
    [...]
    $ readlink [...]/install/offload-amdgcn-amdhsa/amdgcn-amdhsa/bin/as
    /usr/bin/llvm-mc-9
    $ dpkg -S /usr/bin/llvm-mc-9
    llvm-9: /usr/bin/llvm-mc-9
    $ apt-cache policy llvm-9
    llvm-9:
      Installed: 1:9-2~ubuntu18.04.2
    [...]

As this is a problem in an external tool, are we going to declare this "not our
problem", hoping it'll go away in a later release?  Or, do we intent to be
compatible with this LLVM version, and inspect whether there maybe is an actual
issue with GCC's amdgcn code generation that triggers this problem?

Same for 'libgomp.c++' variant.

Supposedly same problem for:

    [-PASS:-]{+FAIL: libgomp.c/examples-4/async_target-2.c (internal compiler
error)+}
    {+FAIL:+} libgomp.c/examples-4/async_target-2.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/examples-4/async_target-2.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/examples-4/target-5.c (internal compiler
error)+}
    {+FAIL:+} libgomp.c/examples-4/target-5.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/examples-4/target-5.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/examples-4/target_data-6.c (internal compiler
error)+}
    {+FAIL:+} libgomp.c/examples-4/target_data-6.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/examples-4/target_data-6.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/examples-4/target_data-7.c (internal compiler
error)+}
    {+FAIL:+} libgomp.c/examples-4/target_data-7.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/examples-4/target_data-7.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/pr86660.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/pr86660.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/pr86660.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/target-3.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/target-3.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/target-3.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/target-4.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/target-4.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/target-4.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/target-5.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/target-5.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/target-5.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/target-6.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/target-6.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/target-6.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c/target-7.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/target-7.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/target-7.c [-execution
test-]{+compilation failed to produce executable+}

    {+FAIL: libgomp.c/thread-limit-2.c (internal compiler error)+}
    FAIL: libgomp.c/thread-limit-2.c (test for excess errors)
    UNRESOLVED: libgomp.c/thread-limit-2.c compilation failed to produce
executable

    [-PASS:-]{+FAIL: libgomp.c/thread-limit-3.c (internal compiler error)+}
    {+FAIL:+} libgomp.c/thread-limit-3.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/thread-limit-3.c [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c++/for-15.C (internal compiler error)+}
    {+FAIL:+} libgomp.c++/for-15.C (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c++/for-15.C [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c++/for-24.C (internal compiler error)+}
    {+FAIL:+} libgomp.c++/for-24.C (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c++/for-24.C [-execution
test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL: libgomp.c++/pr69555-2.C (internal compiler error)+}
    {+FAIL:+} libgomp.c++/pr69555-2.C (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c++/pr69555-2.C [-execution
test-]{+compilation failed to produce executable+}

And, for 'libgomp.oacc-*' (with all "execution test" etc. FAILs ignored as
"[n/a]"; "libgomp: device type gcn not supported" due to running on unsuitable
hardware):

    PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/abort-2.c
-DACC_DEVICE_TYPE_gcn=1 -DACC_MEM_SHARED=0 -foffload=amdgcn-amdhsa  -O0  (test
for excess errors)
    [n/a]: libgomp.oacc-c/../libgomp.oacc-c-c++-common/abort-2.c
-DACC_DEVICE_TYPE_gcn=1 -DACC_MEM_SHARED=0 -foffload=amdgcn-amdhsa  -O0 
execution test
    FAIL: libgomp.oacc-c/../libgomp.oacc-c-c++-common/abort-2.c
-DACC_DEVICE_TYPE_gcn=1 -DACC_MEM_SHARED=0 -foffload=amdgcn-amdhsa  -O2 
(internal compiler error)
    FAIL: libgomp.oacc-c/../libgomp.oacc-c-c++-common/abort-2.c
-DACC_DEVICE_TYPE_gcn=1 -DACC_MEM_SHARED=0 -foffload=amdgcn-amdhsa  -O2  (test
for excess errors)
    UNRESOLVED: libgomp.oacc-c/../libgomp.oacc-c-c++-common/abort-2.c
-DACC_DEVICE_TYPE_gcn=1 -DACC_MEM_SHARED=0 -foffload=amdgcn-amdhsa  -O2 
compilation failed to produce executable