Bug 102429 - nvptx: ICE with expand_GOMP_SIMT_XCHG_BFLY : in expand_insn, at optabs.c:7947 for DCmode (complex double)
Summary: nvptx: ICE with expand_GOMP_SIMT_XCHG_BFLY : in expand_insn, at optabs.c:7947...
Status: RESOLVED FIXED
Alias: None
Product: gcc
Classification: Unclassified
Component: target (show other bugs)
Version: 12.0
: P3 normal
Target Milestone: 12.0
Assignee: Not yet assigned to anyone
URL:
Keywords: ice-on-valid-code
Depends on:
Blocks:
 
Reported: 2021-09-21 18:22 UTC by Tobias Burnus
Modified: 2022-03-01 08:03 UTC (History)
1 user (show)

See Also:
Host:
Target: nvptx
Build:
Known to work:
Known to fail:
Last reconfirmed:

Attachments
testcase, compile with nvptx offloading enabled with: gfortran -fopenmp -O1 (392 bytes, text/plain)
2021-09-21 18:22 UTC, Tobias Burnus 		Details
Tentative patch (1.36 KB, text/plain)
2022-02-28 15:23 UTC, Tom de Vries 		Details
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Tobias Burnus 2021-09-21 18:22:20 UTC 
Created attachment 51490 [details]
testcase, compile with nvptx offloading enabled with: gfortran -fopenmp -O1

That's with several OvO Fortran testcases, the smallest is:
https://github.com/TApplencourt/OvO/blob/master/test_src/fortran/hierarchical_parallelism/reduction_add-double_complex/target_simd.F90

The testcase (also attached) fails with:

  gfortran -fopenmp example.f90 -O1

with:

during RTL pass: expand
example.f90: In function 'MAIN__._omp_fn.0':
example.f90:23:32: internal compiler error: in expand_insn, at optabs.c:7947
   23 |     counter_N0 = counter_N0 + 1.
      |                                ^
0xb21933 expand_insn(insn_code, unsigned int, expand_operand*)
        /net/build5-trusty-cs.sje.mentorg.com/scratch/tburnus/openacc.x86_64-linux-gnu-openacc-mainline/src/gcc-mainline/gcc/optabs.c:7947
0x9761ad expand_GOMP_SIMT_XCHG_BFLY
        /net/build5-trusty-cs.sje.mentorg.com/scratch/tburnus/openacc.x86_64-linux-gnu-openacc-mainline/src/gcc-mainline/gcc/internal-fn.c:375
0x700897 expand_call_stmt

Namely:

expand_insn (icode=CODE_FOR_omp_simt_xchg_bfly, nops=nops@entry=3, ops=ops@entry=0x7fffffffda80)

fails at:

7946      if (!maybe_expand_insn (icode, nops, ops))
7947        gcc_unreachable ();

(gdb) p *ops
$4 = {type = EXPAND_OUTPUT, unsigned_p = 0, target = 0, unused = 0, mode = E_DCmode, value = 0x7ffff73fcc78, int_value = {<poly_int_pod<1u, long>> = {coeffs = {0}}, <No data fields>}}
Comment 1 Tom de Vries 2022-02-28 15:23:29 UTC 
Created attachment 52524 [details]
Tentative patch
Comment 2 GCC Commits 2022-03-01 08:00:08 UTC 
The master branch has been updated by Tom de Vries <vries@gcc.gnu.org>:

https://gcc.gnu.org/g:c2e0d0c1cfb4bf29daed189b39885841ee201a65

commit r12-7425-gc2e0d0c1cfb4bf29daed189b39885841ee201a65
Author: Tom de Vries <tdevries@suse.de>
Date:   Mon Feb 28 16:06:54 2022 +0100

    [nvptx] Handle DCmode in define_expand "omp_simt_xchg_{bfly,idx}"
    
    For a test-case doing an openmp target simd reduction on a complex double:
    ...
      DOUBLE COMPLEX :: counter_N0
      ...
      !$OMP TARGET SIMD reduction(+: counter_N0)
    ...
    we run into:
    ...
    during RTL pass: expand
    b.f90: In function âMAIN__._omp_fn.0â:
    b.f90:23:32: internal compiler error: in expand_insn, at optabs.cc:8029
       23 |     counter_N0 = counter_N0 + 1.
          |                                ^
    0x10f1cd3 expand_insn(insn_code, unsigned int, expand_operand*)
            gcc/optabs.cc:8029
    0xeac435 expand_GOMP_SIMT_XCHG_BFLY
            gcc/internal-fn.cc:375
    ...
    
    Fix this by handling DCmode and CDImode in define_expand
    "omp_simt_xchg_{bfly,idx}".
    
    Tested on x86_64 with nvptx accelerator.
    
    gcc/ChangeLog:
    
    2022-02-28  Tom de Vries  <tdevries@suse.de>
    
            PR target/102429
            * config/nvptx/nvptx.cc (nvptx_gen_shuffle): Handle DCmode and CDImode.
            * config/nvptx/nvptx.md
            (define_predicate "nvptx_register_or_complex_di_df_register_operand"):
            New predicate.
            (define_expand "omp_simt_xchg_bfly", define_expand "omp_simt_xchg_idx"):
            Use nvptx_register_or_complex_di_df_register_operand.
Comment 3 Tom de Vries 2022-03-01 08:03:34 UTC 
Fixed by '[nvptx] Handle DCmode in define_expand "omp_simt_xchg_{bfly,idx}"'.