[Bug ada/66217] New: PowerPC rotate/shift/mask instructions not optimal

[Bug ada/66217] New: PowerPC rotate/shift/mask instructions not optimal

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66217

            Bug ID: 66217
           Summary: PowerPC rotate/shift/mask instructions not optimal
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: segher at gcc dot gnu.org
          Reporter: segher at gcc dot gnu.org
  Target Milestone: ---
            Target: powerpc*-*-*

GCC does not generate optimal instruction sequences for rotate/shift/mask
sequences; it pretty often makes quite bad code, even, esp. when it
involves 64-bit instructions.

One part of the problem is that the masks we allow are less general
than what the hardware allows.  Not a huge problem for the rlwinm
instructions, but we shouldn't need "mask_operand_wrap" there either.

Another big part of the problem is our rtx_cost function does not
handle rotate-and-mask correctly; it recurses to get the cost of
the mask, but then it looks at the mode of it, which is VOIDmode
(it is a const_int), and things go south.

It would be nice to not need that rtx_cost at all, certainly not
for combine  (which has access to full insns always), but that is
a bigger project.

Another problem is with the insert insns.  They are not as general
as they should be, as before.  Also, we should be able to handle
things like (a << 16) | (b >> 16), which is an insert insn followed
by a "normal" rotate (or the other way around).  This should also
make the bswap patterns a little bit simpler.

[Bug ada/66217] PowerPC rotate/shift/mask instructions not optimal

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66217

David Edelsohn <dje at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-05-20
                 CC|                            |dje at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from David Edelsohn <dje at gcc dot gnu.org> ---
Confirmed.

[Bug target/66217] PowerPC rotate/shift/mask instructions not optimal

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66217

--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Mon Jul 20 16:30:56 2015
New Revision: 226005

URL: https://gcc.gnu.org/viewcvs?rev=226005&root=gcc&view=rev
Log:
        PR target/66217
        * config/rs6000/constraints.md ("S", "T", "t"): Delete.  Update
        "available letters" comment.
        * config/rs6000/predicates.md (mask_operand, mask_operand_wrap,
        mask64_operand, mask64_2_operand, any_mask_operand, and64_2_operand,
        and_2rld_operand):  Delete.
        (and_operand): Adjust.
        (rotate_mask_operator): New.
        * config/rs6000/rs6000-protos.h (build_mask64_2_operands,
        includes_lshift_p, includes_rshift_p, includes_rldic_lshift_p,
        includes_rldicr_lshift_p, insvdi_rshift_rlwimi_p, extract_MB,
        extract_ME): Delete.
        (rs6000_is_valid_mask, rs6000_is_valid_and_mask,
        rs6000_is_valid_shift_mask, rs6000_is_valid_insert_mask,
        rs6000_insn_for_and_mask, rs6000_insn_for_shift_mask,
        rs6000_insn_for_insert_mask, rs6000_is_valid_2insn_and,
        rs6000_emit_2insn_and): New.
        * config/rs6000/rs6000.c (num_insns_constant): Adjust.
        (build_mask64_2_operands, includes_lshift_p, includes_rshift_p,
        includes_rldic_lshift_p, includes_rldicr_lshift_p,
        insvdi_rshift_rlwimi_p, extract_MB, extract_ME): Delete.
        (rs6000_is_valid_mask, rs6000_is_valid_and_mask,
        rs6000_insn_for_and_mask, rs6000_is_valid_shift_mask,
        s6000_insn_for_shift_mask, rs6000_is_valid_insert_mask,
        rs6000_insn_for_insert_mask, rs6000_is_valid_2insn_and,
        rs6000_emit_2insn_and): New.
        (print_operand) <'b', 'B', 'm', 'M', 's', 'S', 'W'>: Delete.
        (rs6000_rtx_costs) <CONST_INT>: Delete mask_operand and mask64_operand
        handling.
        <NOT>: Don't fall through to next case.
        <AND>: Handle the various rotate-and-mask cases directly.
        <IOR>: Always cost as one insn.
        * config/rs6000/rs6000.md (splitter for bswap:SI): Adjust.
        (and<mode>3): Adjust expander for the new patterns.
        (and<mode>3_imm, and<mode>3_imm_dot, and<mode>3_imm_dot2,
        and<mode>3_imm_mask_dot, and<mode>3_imm_mask_dot2): Adjust condition.
        (*and<mode>3_imm_dot_shifted): New.
        (*and<mode>3_mask): Delete, rewrite as ...
        (and<mode>3_mask): ... New.
        (*and<mode>3_mask_dot, *and<mode>3_mask_dot): Rewrite.
        (andsi3_internal0_nomc): Delete.
        (*andsi3_internal6): Delete.
        (*and<mode>3_2insn): New.
        (insv, insvsi_internal, *insvsi_internal1, *insvsi_internal2,
        *insvsi_internal3, *insvsi_internal4, *insvsi_internal5,
        *insvsi_internal6, insvdi_internal, *insvdi_internal2,
        *insvdi_internal3): Delete.
        (*rotl<mode>3_mask, *rotl<mode>3_mask_dot, *rotl<mode>3_mask_dot2,
        *rotl<mode>3_insert, *rotl<mode>3_insert_2, *rotl<mode>3_insert_3,
        *rotl<mode>3_insert_4, two splitters for multi-precision shifts,
        *ior<mode>_mask): New.
        (extzv, extzvdi_internal, *extzvdi_internal1, *extzvdi_internal2,
        *rotlsi3_mask, *rotlsi3_mask_dot, *rotlsi3_mask_dot2,
        *ashlsi3_imm_mask, *ashlsi3_imm_mask_dot, *ashlsi3_imm_mask_dot2,
        *lshrsi3_imm_mask, *lshrsi3_imm_mask_dot, *lshrsi3_imm_mask_dot2):
        Delete.
        (ashr<mode>3): Delete expander.
        (*ashr<mode>3): Rename to ...
        (ashr<mode>3): ... This.
        (ashrdi3_no_power, *ashrdisi3_noppc64be): Delete.
        (*rotldi3_internal4, *rotldi3_internal5 and split,
        *rotldi3_internal6 and split, *ashldi3_internal4, ashldi3_internal5
        and split, *ashldi3_internal6 and split, *ashldi3_internal7,
        ashldi3_internal8 and split, *ashldi3_internal9 and split): Delete.
        (*anddi3_2rld, *anddi3_2rld_dot, *anddi3_2rld_dot2): Delete.
        (splitter for loading a mask): Adjust.
        * doc/md.texi (Machine Constraints): Remove q, S, T, t constraints.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/constraints.md
    trunk/gcc/config/rs6000/predicates.md
    trunk/gcc/config/rs6000/rs6000-protos.h
    trunk/gcc/config/rs6000/rs6000.c
    trunk/gcc/config/rs6000/rs6000.md
    trunk/gcc/doc/md.texi

[Bug target/66217] PowerPC rotate/shift/mask instructions not optimal

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66217

David Edelsohn <dje at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |6.0

--- Comment #3 from David Edelsohn <dje at gcc dot gnu.org> ---
Fixed!

[Bug target/66217] PowerPC rotate/shift/mask instructions not optimal

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66217

--- Comment #4 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Thu Jul 23 14:37:57 2015
New Revision: 226112

URL: https://gcc.gnu.org/viewcvs?rev=226112&root=gcc&view=rev
Log:
        PR target/66217
        * config/rs6000/rs6000-protos.h (rs6000_emit_2insn_and): Change
        prototype.
        * config/rs6000/rs6000.c (rs6000_emit_dot_insn): New function.
        (rs6000_emit_2insn_and): Handle dot forms.
        * config/rs6000/rs6000.md (and<mode>3): Adjust.
        (*and<mode>3_2insn): Remove TODO.  Adjust.  Add "type" attr.
        (*and<mode>3_2insn_dot, *and<mode>3_2insn_dot2): New.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/rs6000-protos.h
    trunk/gcc/config/rs6000/rs6000.c
    trunk/gcc/config/rs6000/rs6000.md

[Bug target/66217] PowerPC rotate/shift/mask instructions not optimal

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66217

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Thu Jul 30 02:34:09 2015
New Revision: 226378

URL: https://gcc.gnu.org/viewcvs?rev=226378&root=gcc&view=rev
Log:
        PR target/66217
        PR target/67045
        * config/rs6000/rs6000.md (and<mode>3): Put a CONST_INT_P check
        around those cases that need one.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/rs6000.md