[Bug libgomp/58462] New: gomp4: invalid controlling predicate for != (< is ok)

[Bug libgomp/58462] New: gomp4: invalid controlling predicate for != (< is ok)

[vincenzo.innocente at cern dot ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58462

            Bug ID: 58462
           Summary: gomp4: invalid controlling predicate for != (< is ok)
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgomp
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vincenzo.innocente at cern dot ch
                CC: jakub at gcc dot gnu.org

took me years to learn and teach to use != instead of "<"….

float a[1024];
float b[1024];

void err() {
#pragma omp simd
  for (int i=0;i!=1024;++i) {
    a[i]=b[i];
  }

}

void ok() {
#pragma omp simd
  for (int i=0;i<1024;++i) {
    a[i]=b[i];
  }
}


c++ -std=c++11 -O2 -march=core-avx2 -S twoif.cc  -fopenmp
twoif.cc: In function ‘void err()’:
twoif.cc:7:3: error: invalid controlling predicate
   for (int i=0;i!=1024;++i) {
   ^
pb-d-128-141-131-26:vectorize innocent$ c++ -v
Using built-in specs.
COLLECT_GCC=c++
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-apple-darwin12.4.0/4.9.0/lto-wrapper
Target: x86_64-apple-darwin12.4.0
Configured with: ./configure --disable-multilib --disable-bootstrap
--enable-lto -disable-libitm --enable-languages=c,c++,fortran,lto
--disable-libsanitizer
Thread model: posix
gcc version 4.9.0 20130918 (experimental) (GCC)
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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libgomp/58462] gomp4: invalid controlling predicate for != (< is ok)
Date: Wed, 18 Sep 2013 13:21:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idX462

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
That is invalid.
See OpenMP 4.0, section 2.6.
!= is valid only in Cilk+ (i.e. #pragma simd).

[Bug libgomp/58462] gomp4: invalid controlling predicate for != (< is ok)

[vincenzo.innocente at cern dot ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58462

--- Comment #2 from vincenzo Innocente <vincenzo.innocente at cern dot ch> ---
Thanks Jakub.
Downloaded the standard.
waiting for more examples of usage
It is a pity that it does not support c++ range loop

Let me highjack this bug to congratulate you and your collaborators for the
great and fast work to implement openmp 4.0 simd syntax.

I already found out that at the moment is the only way to convince gcc that a
pointer is "restrict"!

I hope it will go in main-stream 4.9 soon.


Vincenzo