[Bug tree-optimization/102819] [11 Regression] IFN_COMPLEX_MUL matches things that it shouldn't

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102819

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Tamar Christina
<tnfchris@gcc.gnu.org>:

https://gcc.gnu.org/g:876e7c7f0fe47bae7c1922e2683ccb5e6e3ec9fe

commit r11-9621-g876e7c7f0fe47bae7c1922e2683ccb5e6e3ec9fe
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Fri Feb 25 11:59:32 2022 +0000

    vect: Simplify and extend the complex numbers validation routines. (GCC-11
Backport)

    This is a backport of the GCC 12 patch backporting only the correctness
part of
    the fix.   This also backports two small helper functions and documentation
    update on the optabs.

    The patch boosts the analysis for complex mul,fma and fms in order to
ensure
    that it doesn't create an incorrect output.

    Essentially it adds an extra verification to check that the two nodes it's
going
    to combine do the same operations on compatible values.  The reason it
needs to
    do this is that if one computation differs from the other then with the
current
    implementation we have no way to deal with it since we have to remove the
    permute.

    When we can keep the permute around we can probably handle these by
unrolling.

    While implementing this since I have to do the traversal anyway I took
advantage
    of it by simplifying the code a bit.  Previously we would determine whether
    something is a conjugate and then try to figure out which conjugate it is
and
    then try to see if the permutes match what we expect.

    Now the code that does the traversal will detect this in one go and return
to us
    whether the operation is something that can be combined and whether a
conjugate
    is present.

    Secondly because it does this I can now simplify the checking code itself
to
    essentially just try to apply fixed patterns to each operation.

    The patterns represent the order operations should appear in. For instance
a
    complex MUL operation combines :

      Left 1 + Right 1
      Left 2 + Right 2

    with a permute on the nodes consisting of:

      { Even, Even } + { Odd, Odd  }
      { Even, Odd  } + { Odd, Even }

    By abstracting over these patterns the checking code becomes quite simple.

    As part of this I was checking the order of the operands which was left in
    "slp" order. as in, the same order they showed up in during SLP, which
means
    that the accumulator is first.  However it looks like I didn't document
this.

    gcc/ChangeLog:

            PR tree-optimization/102819
            PR tree-optimization/103169
            * gimple.h (gimple_num_args, gimple_arg): New.
            * doc/md.texi: Update docs for cfms, cfma.
            * tree-data-ref.h (same_data_refs): Accept optional offset.
            * tree-vect-slp-patterns.c (is_linear_load_p): Fix issue with
repeating
            patterns.
            (vect_normalize_conj_loc): Remove.
            (is_eq_or_top): Change to take two nodes.
            (enum _conj_status, compatible_complex_nodes_p,
            vect_validate_multiplication): New.
            (class complex_add_pattern, complex_add_pattern::matches,
            complex_add_pattern::recognize, class complex_mul_pattern,
            complex_mul_pattern::recognize, class complex_fms_pattern,
            complex_fms_pattern::recognize,, class complex_fma_pattern,
            complex_fma_pattern::recognize, class complex_operations_pattern,
            complex_operations_pattern::recognize, addsub_pattern::recognize):
Pass
            new cache.
            (complex_fms_pattern::matches, complex_fma_pattern::matches,
            complex_mul_pattern::matches): Pass new cache and use new
validation
            code.
            * tree-vect-slp.c (vect_match_slp_patterns_2,
vect_match_slp_patterns,
            vect_analyze_slp): Pass along cache.
            (compatible_calls_p): Expose.
            * tree-vectorizer.h (compatible_calls_p, slp_node_hash,
            slp_compat_nodes_map_t): New.
            (class vect_pattern): Update signatures include new cache.

    gcc/testsuite/ChangeLog:

            PR tree-optimization/102819
            PR tree-optimization/103169
            * g++.dg/vect/pr99149.cc: xfail for now.
            * gcc.dg/vect/complex/pr102819-1.c: New test.
            * gcc.dg/vect/complex/pr102819-2.c: New test.
            * gcc.dg/vect/complex/pr102819-3.c: New test.
            * gcc.dg/vect/complex/pr102819-4.c: New test.
            * gcc.dg/vect/complex/pr102819-5.c: New test.
            * gcc.dg/vect/complex/pr102819-6.c: New test.
            * gcc.dg/vect/complex/pr102819-7.c: New test.
            * gcc.dg/vect/complex/pr102819-8.c: New test.
            * gcc.dg/vect/complex/pr102819-9.c: New test.
            * gcc.dg/vect/complex/pr103169.c: New test.