Tamar Christina <tamar.christ...@arm.com> writes:
>> > The principle is that, say:
>> >
>> > (vec_select:V2SI (reg:V2DI R) (parallel [(const_int 0) (const_int 1)]))
>> >
>> > is (for little-endian) equivalent to:
>> >
>> > (subreg:V2SI (reg:V2DI R) 0)
>>
>> Sigh, of course I meant V4SI rather than V2DI in the above :)
>>
>> > and similarly for the equivalent big-endian pair. Simplification rules
>> > are now supposed to ensure that only the second (simpler) form is generated
>> > by target-independent code. We should fix any cases where that doesn't
>> > happen, since it would be a missed optimisation for any instructions
>> > that take (in this case) V2SI inputs.
>> >
>> > There's no equivalent simplification for _hi because it isn't possible
>> > to refer directly to the upper 64 bits of a 128-bit register using subregs.
>> >
>
> This removes aarch64_simd_vec_unpack<su>_lo_.
>
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
>
> Ok for master?
>
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> * config/aarch64/aarch64-simd.md
> (aarch64_simd_vec_unpack<su>_lo_<mode>): Remove.
> (vec_unpack<su>_lo_<mode): Simplify.
> * config/aarch64/aarch64.cc (aarch64_gen_shareable_zero): Update
> comment.
OK, thanks.
Richard
> -- inline copy of patch --
>
> diff --git a/gcc/config/aarch64/aarch64-simd.md
> b/gcc/config/aarch64/aarch64-simd.md
> index
> fd10039f9a27d0da51624d6d3a6d8b2a532f5625..bbeee221f37c4875056cdf52932a787f8ac1c2aa
> 100644
> --- a/gcc/config/aarch64/aarch64-simd.md
> +++ b/gcc/config/aarch64/aarch64-simd.md
> @@ -1904,17 +1904,6 @@ (define_insn
> "*aarch64_<srn_op>topbits_shuffle<mode>_be"
>
> ;; Widening operations.
>
> -(define_insn "aarch64_simd_vec_unpack<su>_lo_<mode>"
> - [(set (match_operand:<VWIDE> 0 "register_operand" "=w")
> - (ANY_EXTEND:<VWIDE> (vec_select:<VHALF>
> - (match_operand:VQW 1 "register_operand" "w")
> - (match_operand:VQW 2 "vect_par_cnst_lo_half" "")
> - )))]
> - "TARGET_SIMD"
> - "<su>xtl\t%0.<Vwtype>, %1.<Vhalftype>"
> - [(set_attr "type" "neon_shift_imm_long")]
> -)
> -
> (define_insn_and_split "aarch64_simd_vec_unpack<su>_hi_<mode>"
> [(set (match_operand:<VWIDE> 0 "register_operand" "=w")
> (ANY_EXTEND:<VWIDE> (vec_select:<VHALF>
> @@ -1952,14 +1941,11 @@ (define_expand "vec_unpack<su>_hi_<mode>"
> )
>
> (define_expand "vec_unpack<su>_lo_<mode>"
> - [(match_operand:<VWIDE> 0 "register_operand")
> - (ANY_EXTEND:<VWIDE> (match_operand:VQW 1 "register_operand"))]
> + [(set (match_operand:<VWIDE> 0 "register_operand")
> + (ANY_EXTEND:<VWIDE> (match_operand:VQW 1 "register_operand")))]
> "TARGET_SIMD"
> {
> - rtx p = aarch64_simd_vect_par_cnst_half (<MODE>mode, <nunits>, false);
> - emit_insn (gen_aarch64_simd_vec_unpack<su>_lo_<mode> (operands[0],
> - operands[1], p));
> - DONE;
> + operands[1] = lowpart_subreg (<VHALF>mode, operands[1], <MODE>mode);
> }
> )
>
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index
> 6b106a72e49f11b8128485baceaaaddcbf139863..469eb938953a70bc6b0ce3d4aa16f773e40ee03e
> 100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -23188,7 +23188,8 @@ aarch64_gen_shareable_zero (machine_mode mode)
> to split without that restriction and instead recombine shared zeros
> if they turn out not to be worthwhile. This would allow splits in
> single-block functions and would also cope more naturally with
> - rematerialization. */
> + rematerialization. The downside of not doing this is that we lose the
> + optimizations for vector epilogues as well. */
>
> bool
> aarch64_split_simd_shift_p (rtx_insn *insn)
