[Bug c++/66676] New: pragma omp simd aligned(x) results in "internal compiler error: Segmentation fault"

[Bug c++/66676] New: pragma omp simd aligned(x) results in "internal compiler error: Segmentation fault"

[schreiberx at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66676

            Bug ID: 66676
           Summary: pragma omp simd aligned(x) results in "internal
                    compiler error: Segmentation fault"
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: schreiberx at gmail dot com
  Target Milestone: ---

Created attachment 35855
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35855&action=edit
reproducer of bug

The Compiler segfaults if declaring a function with

  #pragma omp declare simd aligned(i_x)
   void ODEBenchmark_OpenMP_ver2(double *i_x){}

By specifying the alignment such as via
   #pragma omp declare simd aligned(i_x:128)
   void ODEBenchmark_OpenMP_ver2(double *i_x){}
compiles the program.

GCC version 5.1.0

Compile attached source code with
g++ -fopenmp ODEBenchmark.cpp
to reproduce bug.

[Bug c++/66676] pragma omp simd aligned(x) results in "internal compiler error: Segmentation fault"

[schreiberx at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66676

Martin Schreiber <schreiberx at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |major

[Bug c++/66676] pragma omp simd aligned(x) results in "internal compiler error: Segmentation fault"

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66676

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
           Severity|major                       |normal

[Bug c++/66676] pragma omp simd aligned(x) results in "internal compiler error: Segmentation fault"

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66676

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |openmp
                 CC|                            |iverbin at gcc dot gnu.org,
                   |                            |kyukhin at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
For the "implementation defined" alignment, omp-low.c normally uses
omp_clause_aligned_alignment function to compute the alignment, but
unfortunately that is very much dependent on the ISA options.
When it is used in declare simd, it is unfortunately part of the ABI.
I can't seem to find anything about that case in the Intel ABI document
(version 0.9.7 or older).  Looking at what (older) icc emits, it seems it uses
alignment of 1 (i.e. a useless, but safe alignment), is that what we want to
put into the ABI?

Note, aligned attribute doesn't really make much sense on non-uniform arguments
(especially in this case when it is passed as a vector of pointers).  Plus the
array really isn't aligned any way, so it is unlikely it will be aligned say if
you use aligned(i_x:128) uniform(i_x).