[PATCH PR96357][GCC][AArch64]: could not split insn UNSPEC_COND_FSUB with AArch64 SVE

[Richard Sandiford]

Przemyslaw Wirkus <Przemyslaw.Wirkus@arm.com> writes:
> @@ -5234,21 +5234,21 @@ (define_insn_and_rewrite "*cond_sub<mode>_3_const"
>  
>  ;; Predicated floating-point subtraction from a constant, merging with an
>  ;; independent value.
> -(define_insn_and_rewrite "*cond_sub<mode>_any_const"
> +;; The subtraction predicate and the merge predicate are allowed to be
> +;; different.

Sorry for the micromanagement, but I think this is easier to read if it
flows as a single paragraph:

;; Predicated floating-point subtraction from a constant, merging with an
;; independent value.  The subtraction predicate and the merge predicate are
;; allowed to be different.

or is written as two separate paragraphs:

;; Predicated floating-point subtraction from a constant, merging with an
;; independent value.
;;
;; The subtraction predicate and the merge predicate are allowed to be
;; different.

Same for the second comment.

> @@ -5271,6 +5271,41 @@ (define_insn_and_rewrite "*cond_sub<mode>_any_const"
>    [(set_attr "movprfx" "yes")]
>  )
>  
> +;; Predicated floating-point subtraction from a constant, merging with an
> +;; independent value.
> +;; The subtraction predicate and the merge predicate must be the same.
> +(define_insn_and_rewrite "*cond_sub<mode>_strict_const"
> +  [(set (match_operand:SVE_FULL_F 0 "register_operand" "=w, w, ?w")
> +	(unspec:SVE_FULL_F
> +	  [(match_operand:<VPRED> 1 "register_operand" "Upl, Upl, Upl")
> +	   (unspec:SVE_FULL_F
> +	     [(match_dup 1)
> +	      (const_int SVE_STRICT_GP)
> +	      (match_operand:SVE_FULL_F 2 "aarch64_sve_float_arith_immediate")
> +	      (match_operand:SVE_FULL_F 3 "register_operand" "w, w, w")]
> +	     UNSPEC_COND_FSUB)
> +	   (match_operand:SVE_FULL_F 4 "aarch64_simd_reg_or_zero" "Dz, 0, w")]
> +	  UNSPEC_SEL))]
> +  "TARGET_SVE && !rtx_equal_p (operands[3], operands[4])"
> +  "@
> +   movprfx\t%0.<Vetype>, %1/z, %3.<Vetype>\;fsubr\t%0.<Vetype>, %1/m, %0.<Vetype>, #%2
> +   movprfx\t%0.<Vetype>, %1/m, %3.<Vetype>\;fsubr\t%0.<Vetype>, %1/m, %0.<Vetype>, #%2
> +   #"
> +  "&& 1"
> +  {
> +    if (reload_completed
> +        && register_operand (operands[4], <MODE>mode)
> +        && !rtx_equal_p (operands[0], operands[4]))
> +      {
> +	emit_insn (gen_vcond_mask_<mode><vpred> (operands[0], operands[3],
> +						 operands[4], operands[1]));
> +	operands[4] = operands[3] = operands[0];
> +      }
> +    else
> +      FAIL;

I should have realised this would be the case, sorry, but now that there's
only one rewrite, this should simply be:

  "&& reload_completed
   && register_operand (operands[4], <MODE>mode)
   && !rtx_equal_p (operands[0], operands[4]))"
  {
    emit_insn (gen_vcond_mask_<mode><vpred> (operands[0], operands[3],
					     operands[4], operands[1]));
    operands[4] = operands[3] = operands[0];
  }

OK with those changes, thanks.

Richard