Re: [PATCH] internal-fn: Add VCOND_MASK_LEN.

[Richard Sandiford <richard.sandiford@arm.com>]

Robin Dapp <rdapp.gcc@gmail.com> writes:
>> Ah, OK.  IMO it's better to keep the optab operands the same as the IFN
>> operands, even if that makes things inconsistent with vcond_mask.
>> vcond_mask isn't really a good example to follow, since the operand
>> order is not only inconsistent with the IFN, it's also inconsistent
>> with the natural if_then_else order.
>
> v4 attached with that changed,  match.pd patterns interleaved as well
> as scratch-handling added and VLS modes removed.  Lehua has since pushed
> another patch that extends gimple_match_op to 6/7 operands already so
> that could be removed as well making the patch even smaller now.
>
> Testsuite on riscv looks good (apart from the mentioned cond_widen...),
> still running on aarch64 and x86.  OK if those pass?
>
> Regards
>  Robin
>
> Subject: [PATCH v4] internal-fn: Add VCOND_MASK_LEN.
>
> In order to prevent simplification of a COND_OP with degenerate mask
> (CONSTM1_RTX) into just an OP in the presence of length masking this
> patch introduces a length-masked analog to VEC_COND_EXPR:
> IFN_VCOND_MASK_LEN.
>
> It also adds new match patterns that allow the combination of
> unconditional unary, binary and ternay operations with the
> VCOND_MASK_LEN into a conditional operation if the target supports it.
>
> gcc/ChangeLog:
>
> 	PR tree-optimization/111760
>
> 	* config/riscv/autovec.md (vcond_mask_len_<mode><vm>): Add
> 	expander.
> 	* config/riscv/riscv-protos.h (enum insn_type): Add.
> 	* config/riscv/riscv-v.cc (needs_fp_rounding): Add !pred_mov.
> 	* doc/md.texi: Add vcond_mask_len.
> 	* gimple-match-exports.cc (maybe_resimplify_conditional_op):
> 	Create VCOND_MASK_LEN when length masking.
> 	* gimple-match.h (gimple_match_op::gimple_match_op): Always
> 	initialize len and bias.
> 	* internal-fn.cc (vec_cond_mask_len_direct): Add.
> 	(direct_vec_cond_mask_len_optab_supported_p): Add.
> 	(internal_fn_len_index): Add VCOND_MASK_LEN.
> 	(internal_fn_mask_index): Ditto.
> 	* internal-fn.def (VCOND_MASK_LEN): New internal function.
> 	* match.pd: Combine unconditional unary, binary and ternary
> 	operations into the respective COND_LEN operations.
> 	* optabs.def (OPTAB_D): Add vcond_mask_len optab.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.dg/vect/vect-cond-arith-2.c: No vect cost model for
> 	riscv_v.
> ---
>  gcc/config/riscv/autovec.md                   | 26 ++++++++++
>  gcc/config/riscv/riscv-protos.h               |  3 ++
>  gcc/config/riscv/riscv-v.cc                   |  3 +-
>  gcc/doc/md.texi                               |  9 ++++
>  gcc/gimple-match-exports.cc                   | 13 +++--
>  gcc/gimple-match.h                            |  6 ++-
>  gcc/internal-fn.cc                            |  5 ++
>  gcc/internal-fn.def                           |  2 +
>  gcc/match.pd                                  | 51 +++++++++++++++++++
>  gcc/optabs.def                                |  1 +
>  gcc/testsuite/gcc.dg/vect/vect-cond-arith-2.c |  1 +
>  11 files changed, 114 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/config/riscv/autovec.md b/gcc/config/riscv/autovec.md
> index cc4c9596bbf..0a5e4ccb54e 100644
> --- a/gcc/config/riscv/autovec.md
> +++ b/gcc/config/riscv/autovec.md
> @@ -565,6 +565,32 @@ (define_insn_and_split "vcond_mask_<mode><vm>"
>    [(set_attr "type" "vector")]
>  )
>  
> +(define_expand "vcond_mask_len_<mode>"
> +  [(match_operand:V 0 "register_operand")
> +    (match_operand:<VM> 1 "nonmemory_operand")
> +    (match_operand:V 2 "nonmemory_operand")
> +    (match_operand:V 3 "autovec_else_operand")
> +    (match_operand 4 "autovec_length_operand")
> +    (match_operand 5 "const_0_operand")]
> +  "TARGET_VECTOR"
> +  {
> +    if (satisfies_constraint_Wc1 (operands[1]))
> +      riscv_vector::expand_cond_len_unop (code_for_pred_mov (<MODE>mode),
> +					  operands);
> +    else
> +      {
> +	/* The order of then and else is opposite to pred_merge.  */
> +	rtx ops[] = {operands[0], operands[3], operands[3], operands[2],
> +		     operands[1]};
> +	riscv_vector::emit_nonvlmax_insn (code_for_pred_merge (<MODE>mode),
> +					  riscv_vector::MERGE_OP_TU,
> +					  ops, operands[4]);
> +      }
> +    DONE;
> +  }
> +  [(set_attr "type" "vector")]
> +)
> +
>  ;; -------------------------------------------------------------------------
>  ;; ---- [BOOL] Select based on masks
>  ;; -------------------------------------------------------------------------
> diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h
> index a1be731c28e..0d0ee5effea 100644
> --- a/gcc/config/riscv/riscv-protos.h
> +++ b/gcc/config/riscv/riscv-protos.h
> @@ -359,6 +359,9 @@ enum insn_type : unsigned int
>    /* For vmerge, no mask operand, no mask policy operand.  */
>    MERGE_OP = __NORMAL_OP_TA2 | TERNARY_OP_P,
>  
> +  /* For vmerge with TU policy.  */
> +  MERGE_OP_TU = HAS_DEST_P | HAS_MERGE_P | TERNARY_OP_P | TU_POLICY_P,
> +
>    /* For vm<compare>, no tail policy operand.  */
>    COMPARE_OP = __NORMAL_OP_MA | TERNARY_OP_P,
>    COMPARE_OP_MU = __MASK_OP_MU | TERNARY_OP_P,
> diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
> index b489ce08775..d2dde1897c4 100644
> --- a/gcc/config/riscv/riscv-v.cc
> +++ b/gcc/config/riscv/riscv-v.cc
> @@ -3214,7 +3214,8 @@ needs_fp_rounding (unsigned icode, machine_mode mode)
>  	 && icode != maybe_code_for_pred_widen (FLOAT, mode)
>  	 && icode != maybe_code_for_pred_widen (UNSIGNED_FLOAT, mode)
>  	 /* vfsgnj */
> -	 && icode != maybe_code_for_pred (UNSPEC_VCOPYSIGN, mode);
> +	 && icode != maybe_code_for_pred (UNSPEC_VCOPYSIGN, mode)
> +	 && icode != maybe_code_for_pred_mov (mode);
>  }
>  
>  /* Subroutine to expand COND_LEN_* patterns.  */
> diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
> index fab2513105a..10f971749bc 100644
> --- a/gcc/doc/md.texi
> +++ b/gcc/doc/md.texi
> @@ -5306,6 +5306,15 @@ no need to define this instruction pattern if the others are supported.
>  Similar to @code{vcond@var{m}@var{n}} but operand 3 holds a pre-computed
>  result of vector comparison.
>  
> +@cindex @code{vcond_mask_len_@var{m}@var{n}} instruction pattern
> +@item @samp{vcond_mask_@var{m}@var{n}}
> +Similar to @code{vcond_mask@var{m}@var{n}} but operand 4 holds a variable
> +or constant length and operand 5 holds a bias.  If the
> +element index < operand 4 + operand 5 the respective element of the result is
> +computed as in @code{vcond_mask_@var{m}@var{n}}.  For element indices >=
> +operand 4 + operand 5 the computation is performed as if the respective mask
> +element were zero.
> +

There is no computation here, it's just a selection between two values.
We should also mention the different operand order.  How about:

----------------
Set each element of operand 0 to the corresponding element of operand 2
or operand 3.  Choose operand 2 if both the element index is less than
operand 4 plus operand 5 and the corresponding element of operand 1
is nonzero:

@smallexample
for (i = 0; i < GET_MODE_NUNITS (@var{m}); i++)
  op0[i] = i < op4 + op5 && op1[i] ? op2[i] : op3[i];
@end smallexample

Operands 0, 2 and 3 have mode @var{m}.  Operand 1 has mode @var{n}.
Operands 4 and 5 have a target-dependent scalar integer mode.
----------------

OK for the non-match.pd target-independent parts with that change.

Thanks,
Richard

>  @cindex @code{maskload@var{m}@var{n}} instruction pattern
>  @item @samp{maskload@var{m}@var{n}}
>  Perform a masked load of vector from memory operand 1 of mode @var{m}
> diff --git a/gcc/gimple-match-exports.cc b/gcc/gimple-match-exports.cc
> index b36027b0bad..d6dac08cc2b 100644
> --- a/gcc/gimple-match-exports.cc
> +++ b/gcc/gimple-match-exports.cc
> @@ -307,9 +307,16 @@ maybe_resimplify_conditional_op (gimple_seq *seq, gimple_match_op *res_op,
>        && VECTOR_TYPE_P (res_op->type)
>        && gimple_simplified_result_is_gimple_val (res_op))
>      {
> -      new_op.set_op (VEC_COND_EXPR, res_op->type,
> -		     res_op->cond.cond, res_op->ops[0],
> -		     res_op->cond.else_value);
> +      tree len = res_op->cond.len;
> +      if (!len)
> +	new_op.set_op (VEC_COND_EXPR, res_op->type,
> +		       res_op->cond.cond, res_op->ops[0],
> +		       res_op->cond.else_value);
> +      else
> +	new_op.set_op (IFN_VCOND_MASK_LEN, res_op->type,
> +		       res_op->cond.cond, res_op->ops[0],
> +		       res_op->cond.else_value,
> +		       res_op->cond.len, res_op->cond.bias);
>        *res_op = new_op;
>        return gimple_resimplify3 (seq, res_op, valueize);
>      }
> diff --git a/gcc/gimple-match.h b/gcc/gimple-match.h
> index 9892c142285..63a9f029589 100644
> --- a/gcc/gimple-match.h
> +++ b/gcc/gimple-match.h
> @@ -32,7 +32,8 @@ public:
>    enum uncond { UNCOND };
>  
>    /* Build an unconditional op.  */
> -  gimple_match_cond (uncond) : cond (NULL_TREE), else_value (NULL_TREE) {}
> +  gimple_match_cond (uncond) : cond (NULL_TREE), else_value (NULL_TREE), len
> +			       (NULL_TREE), bias (NULL_TREE) {}
>    gimple_match_cond (tree, tree);
>    gimple_match_cond (tree, tree, tree, tree);
>  
> @@ -56,7 +57,8 @@ public:
>  
>  inline
>  gimple_match_cond::gimple_match_cond (tree cond_in, tree else_value_in)
> -  : cond (cond_in), else_value (else_value_in)
> +  : cond (cond_in), else_value (else_value_in), len (NULL_TREE),
> +    bias (NULL_TREE)
>  {
>  }
>  
> diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
> index c7d3564faef..5a998e794ad 100644
> --- a/gcc/internal-fn.cc
> +++ b/gcc/internal-fn.cc
> @@ -170,6 +170,7 @@ init_internal_fns ()
>  #define store_lanes_direct { 0, 0, false }
>  #define mask_store_lanes_direct { 0, 0, false }
>  #define vec_cond_mask_direct { 1, 0, false }
> +#define vec_cond_mask_len_direct { 1, 1, false }
>  #define vec_cond_direct { 2, 0, false }
>  #define scatter_store_direct { 3, 1, false }
>  #define len_store_direct { 3, 3, false }
> @@ -4690,6 +4691,7 @@ internal_fn_len_index (internal_fn fn)
>      case IFN_MASK_LEN_STORE:
>      case IFN_MASK_LEN_LOAD_LANES:
>      case IFN_MASK_LEN_STORE_LANES:
> +    case IFN_VCOND_MASK_LEN:
>        return 3;
>  
>      default:
> @@ -4782,6 +4784,9 @@ internal_fn_mask_index (internal_fn fn)
>      case IFN_MASK_LEN_SCATTER_STORE:
>        return 4;
>  
> +    case IFN_VCOND_MASK_LEN:
> +      return 0;
> +
>      default:
>        return (conditional_internal_fn_code (fn) != ERROR_MARK
>  	      || get_unconditional_internal_fn (fn) != IFN_LAST ? 0 : -1);
> diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
> index a2023ab9c3d..7f0e3759615 100644
> --- a/gcc/internal-fn.def
> +++ b/gcc/internal-fn.def
> @@ -221,6 +221,8 @@ DEF_INTERNAL_OPTAB_FN (VCONDU, ECF_CONST | ECF_NOTHROW, vcondu, vec_cond)
>  DEF_INTERNAL_OPTAB_FN (VCONDEQ, ECF_CONST | ECF_NOTHROW, vcondeq, vec_cond)
>  DEF_INTERNAL_OPTAB_FN (VCOND_MASK, ECF_CONST | ECF_NOTHROW,
>  		       vcond_mask, vec_cond_mask)
> +DEF_INTERNAL_OPTAB_FN (VCOND_MASK_LEN, ECF_CONST | ECF_NOTHROW,
> +		       vcond_mask_len, cond_len_unary)
>  
>  DEF_INTERNAL_OPTAB_FN (VEC_SET, ECF_CONST | ECF_NOTHROW, vec_set, vec_set)
>  DEF_INTERNAL_OPTAB_FN (VEC_EXTRACT, ECF_CONST | ECF_NOTHROW,
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 424bbd02233..dbc811b2b38 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -87,6 +87,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    negate bit_not)
>  (define_operator_list COND_UNARY
>    IFN_COND_NEG IFN_COND_NOT)
> +(define_operator_list COND_LEN_UNARY
> +  IFN_COND_LEN_NEG IFN_COND_LEN_NOT)
>  
>  /* Binary operations and their associated IFN_COND_* function.  */
>  (define_operator_list UNCOND_BINARY
> @@ -8961,6 +8963,21 @@ and,
>          && is_truth_type_for (op_type, TREE_TYPE (@0)))
>       (cond_op (bit_not @0) @2 @1)))))
>  
> +(for uncond_op (UNCOND_UNARY)
> +     cond_op (COND_LEN_UNARY)
> + (simplify
> +  (IFN_VCOND_MASK_LEN @0 (view_convert? (uncond_op@3 @1)) @2 @4 @5)
> +   (with { tree op_type = TREE_TYPE (@3); }
> +    (if (vectorized_internal_fn_supported_p (as_internal_fn (cond_op), op_type)
> +        && is_truth_type_for (op_type, TREE_TYPE (@0)))
> +     (cond_op @0 @1 @2 @4 @5))))
> + (simplify
> +  (IFN_VCOND_MASK_LEN @0 @1 (view_convert? (uncond_op@3 @2)) @4 @5)
> +   (with { tree op_type = TREE_TYPE (@3); }
> +    (if (vectorized_internal_fn_supported_p (as_internal_fn (cond_op), op_type)
> +        && is_truth_type_for (op_type, TREE_TYPE (@0)))
> +     (cond_op (bit_not @0) @2 @1 @4 @5)))))
> +
>  /* `(a ? -1 : 0) ^ b` can be converted into a conditional not.  */
>  (simplify
>   (bit_xor:c (vec_cond @0 uniform_integer_cst_p@1 uniform_integer_cst_p@2) @3)
> @@ -9007,6 +9024,23 @@ and,
>  	&& single_use (@4))
>      (view_convert (cond_op (bit_not @0) @2 @3 (view_convert:op_type @1)))))))
>  
> +(for uncond_op (UNCOND_BINARY)
> +     cond_op (COND_LEN_BINARY)
> + (simplify
> +  (IFN_VCOND_MASK_LEN @0 (view_convert? (uncond_op@4 @1 @2)) @3 @5 @6)
> +  (with { tree op_type = TREE_TYPE (@4); }
> +   (if (vectorized_internal_fn_supported_p (as_internal_fn (cond_op), op_type)
> +	&& is_truth_type_for (op_type, TREE_TYPE (@0))
> +	&& single_use (@4))
> +    (view_convert (cond_op @0 @1 @2 (view_convert:op_type @3) @5 @6)))))
> + (simplify
> +  (IFN_VCOND_MASK_LEN @0 @1 (view_convert? (uncond_op@4 @2 @3)) @5 @6)
> +  (with { tree op_type = TREE_TYPE (@4); }
> +   (if (vectorized_internal_fn_supported_p (as_internal_fn (cond_op), op_type)
> +	&& is_truth_type_for (op_type, TREE_TYPE (@0))
> +	&& single_use (@4))
> +    (view_convert (cond_op (bit_not @0) @2 @3 (view_convert:op_type @1) @5 @6))))))
> +
>  /* Same for ternary operations.  */
>  (for uncond_op (UNCOND_TERNARY)
>       cond_op (COND_TERNARY)
> @@ -9025,6 +9059,23 @@ and,
>  	&& single_use (@5))
>      (view_convert (cond_op (bit_not @0) @2 @3 @4
>  		  (view_convert:op_type @1)))))))
> +
> +(for uncond_op (UNCOND_TERNARY)
> +     cond_op (COND_LEN_TERNARY)
> + (simplify
> +  (IFN_VCOND_MASK_LEN @0 (view_convert? (uncond_op@5 @1 @2 @3)) @4 @6 @7)
> +  (with { tree op_type = TREE_TYPE (@5); }
> +   (if (vectorized_internal_fn_supported_p (as_internal_fn (cond_op), op_type)
> +	&& is_truth_type_for (op_type, TREE_TYPE (@0))
> +	&& single_use (@5))
> +    (view_convert (cond_op @0 @1 @2 @3 (view_convert:op_type @4) @6 @7)))))
> + (simplify
> +  (IFN_VCOND_MASK_LEN @0 @1 (view_convert? (uncond_op@5 @2 @3 @4 @6 @7)))
> +  (with { tree op_type = TREE_TYPE (@5); }
> +   (if (vectorized_internal_fn_supported_p (as_internal_fn (cond_op), op_type)
> +	&& is_truth_type_for (op_type, TREE_TYPE (@0))
> +	&& single_use (@5))
> +    (view_convert (cond_op (bit_not @0) @2 @3 @4 (view_convert:op_type @1) @6 @7))))))
>  #endif
>  
>  /* Detect cases in which a VEC_COND_EXPR effectively replaces the
> diff --git a/gcc/optabs.def b/gcc/optabs.def
> index 2ccbe4197b7..8d5ceeb8710 100644
> --- a/gcc/optabs.def
> +++ b/gcc/optabs.def
> @@ -282,6 +282,7 @@ OPTAB_D (cond_len_fnma_optab, "cond_len_fnma$a")
>  OPTAB_D (cond_len_fnms_optab, "cond_len_fnms$a")
>  OPTAB_D (cond_len_neg_optab, "cond_len_neg$a")
>  OPTAB_D (cond_len_one_cmpl_optab, "cond_len_one_cmpl$a")
> +OPTAB_D (vcond_mask_len_optab, "vcond_mask_len_$a")
>  OPTAB_D (cmov_optab, "cmov$a6")
>  OPTAB_D (cstore_optab, "cstore$a4")
>  OPTAB_D (ctrap_optab, "ctrap$a4")
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-cond-arith-2.c b/gcc/testsuite/gcc.dg/vect/vect-cond-arith-2.c
> index 7e165977e2b..7b3d73acb88 100644
> --- a/gcc/testsuite/gcc.dg/vect/vect-cond-arith-2.c
> +++ b/gcc/testsuite/gcc.dg/vect/vect-cond-arith-2.c
> @@ -1,5 +1,6 @@
>  /* { dg-do compile } */
>  /* { dg-additional-options "-fgimple -fdump-tree-optimized -ffast-math" } */
> +/* { dg-additional-options "-fno-vect-cost-model" { target { riscv_v } } } */
>  
>  double __GIMPLE (ssa, startwith("loop"))
>  neg_xi (double *x)