On Mon, 30 Nov 2009 15:02:48 +0000
Richard Earnshaw <rearnsha@arm.com> wrote:

> I certainly think we shouldn't be hiding knowledge about the element
> to vector-lane mapping from the vectorizer -- and that the vectorizer
> should understand that vector copies are not necessarily the same as
> vectorizing loads.  Anything else and we will ultimately have parts of
> the compiler fighting against each other and that way lies subtle
> bugs.

This is a version of the patch which doesn't attempt to resolve the
discrepancy between vector copies and vectorizing loads/stores (thus is
only intended to work in little-endian mode, leaving big-endian mode as
an open problem). So, vldr/vstr etc. will still be used for aligned
accesses, and any issues with adding semantics to movmisalign<mode> are
sidestepped.

As with previous versions of the patch, there are several new failures
in the vector testsuite.

Ira Rosen <IRAR@il.ibm.com> wrote:
> > > > --- a/gcc/tree-vect-data-refs.c
> > > > +++ b/gcc/tree-vect-data-refs.c
> > > > @@ -796,7 +796,8 @@ vect_compute_data_ref_alignment (struct  
> > > data_reference *dr)  
> > > >    /* At this point we assume that the base is aligned.  */
> > > >    gcc_assert (base_aligned
> > > >           || (TREE_CODE (base) == VAR_DECL
> > > > -           && DECL_ALIGN (base) >= TYPE_ALIGN (vectype)));
> > > > +           && (DECL_ALIGN (base)
> > > > +               >= targetm.vectorize.vector_min_alignment
> > > > (vectype))));  
> > >
> > > Looks like you forgot to multiply by BITS_PER_UNIT here.  
> >
> > Fixed.  
> 
> Not in the attached patch...

(I changed DECL_ALIGN to DECL_ALIGN_UNIT, so both copies of the
inequality were in units, rather than explicitly multiplying by
BITS_PER_UNIT. I should probably have mentioned that...)

OK to apply?

Julian

ChangeLog

    Julian Brown  <julian@codesourcery.com>
    Paul Brook  <paul@codesourcery.com>
    Daniel Jacobowitz  <dan@codesourcery.com>
    Joseph Myers  <joseph@codesourcery.com>

    gcc/
    * target-def.h (TARGET_VECTOR_MIN_ALIGNMENT): Define.
    (TARGET_VECTORIZE): Use above.
    * target.h (gcc_target): Add vectorize.vector_min_alignment.
    * targhooks.c (default_vector_min_alignment): New function.
    * targhooks.h (default_vector_min_alignment): Add prototype.
    * tree-vect-data-refs.c (vect_compute_data_ref_alignment): Use
    targetm.vectorize.vector_min_alignment.
    * tree-vect-loop-manip.c (target.h): Include.
    (vect_gen_niters_for_prolog_loop): Use targetm.vectorize.vector_min_alignment.
    * config/arm/arm.c (arm_vector_min_alignment): New function.
    (TARGET_VECTOR_MIN_ALIGNMENT): Define macro, using above.
    (neon_vector_mem_operand): Disallow PRE_DEC for array loads.
    (arm_print_operand): Include alignment qualifier in %A.
    * config/arm/neon.md (UNSPEC_MISALIGNED_ACCESS): New constant.
    (movmisalign<mode>): New expander.
    (movmisalign<mode>_neon_store, movmisalign<mode>_neon_load): New
    insn patterns.

    gcc/testsuite/
    * lib/target-supports.exp
    (check_effective_target_arm_vect_no_misalign): New function.
    (check_effective_target_vect_no_align): Use above.
    (check_effective_target_vect_element_align): New function.
    * gcc.dg/vect/no-section-anchors-vect-31.c: Use vect_element_align (instead of
    vect_hw_misalign where appropriate).
    * gcc.dg/vect/no-section-anchors-vect-64.c: Ditto.
    * gcc.dg/vect/no-section-anchors-vect-66.c: Ditto.
    * gcc.dg/vect/no-section-anchors-vect-68.c: Ditto.
    * gcc.dg/vect/no-section-anchors-vect-69.c: Ditto.
    * gcc.dg/vect/no-scebccp-outer-8.c: Ditto.
    * gcc.dg/vect/pr25413.c: Ditto.
    * gcc.dg/vect/section-anchors-vect-69.c: Ditto.
    * gcc.dg/vect/slp-25.c: Ditto.
    * gcc.dg/vect/vect-109.c: Ditto.
    * gcc.dg/vect/vect-26.c: Ditto.
    * gcc.dg/vect/vect-27.c: Ditto.
    * gcc.dg/vect/vect-28.c: Ditto.
    * gcc.dg/vect/vect-29.c: Ditto.
    * gcc.dg/vect/vect-33.c: Ditto.
    * gcc.dg/vect/vect-42.c: Ditto.
    * gcc.dg/vect/vect-44.c: Ditto.
    * gcc.dg/vect/vect-48.c: Ditto.
    * gcc.dg/vect/vect-50.c: Ditto.
    * gcc.dg/vect/vect-52.c: Ditto.
    * gcc.dg/vect/vect-54.c: Ditto.
    * gcc.dg/vect/vect-56.c: Ditto.
    * gcc.dg/vect/vect-58.c: Ditto.
    * gcc.dg/vect/vect-60.c: Ditto.
    * gcc.dg/vect/vect-70.c: Ditto.
    * gcc.dg/vect/vect-72.c: Ditto.
    * gcc.dg/vect/vect-75.c: Ditto.
    * gcc.dg/vect/vect-87.c: Ditto.
    * gcc.dg/vect/vect-88.c: Ditto.
    * gcc.dg/vect/vect-89.c: Ditto.
    * gcc.dg/vect/vect-91.c: Ditto.
    * gcc.dg/vect/vect-92.c: Ditto.
    * gcc.dg/vect/vect-93.c: Ditto.
    * gcc.dg/vect/vect-95.c: Ditto.
    * gcc.dg/vect/vect-96.c: Ditto.
    * gcc.dg/vect/vect-align-1.c: Ditto.
    * gcc.dg/vect/vect-align-2.c: Ditto.
    * gcc.dg/vect/vect-multitypes-1.c: Ditto.
    * gcc.dg/vect/vect-multitypes-3.c: Ditto.
    * gcc.dg/vect/vect-multitypes-4.c: Ditto.
    * gcc.dg/vect/vect-multitypes-6.c: Ditto.
    * gfortran.dg/vect/vect-2.f90: Ditto.
    * gfortran.dg/vect/vect-3.f90: Ditto.
    * gfortran.dg/vect/vect-4.f90: Ditto.
    * gfortran.dg/vect/vect-5.f90: Ditto.