recog: Support space in "[ cons"

recog: Support space in "[ cons"

Hi all,

this is to allow for spaces before "cons:" in the definitions of
patterns using the new compact syntax, ex:

(define_insn "aarch64_simd_dup<mode>"
  [(set (match_operand:VDQ_I 0 "register_operand")
        (vec_duplicate:VDQ_I
          (match_operand:<VEL> 1 "register_operand")))]
  "TARGET_SIMD"
  {@ [ cons: =0 , 1  ; attrs: type      ]
     [ w        , w  ; neon_dup<q>      ] dup\t%0.<Vtype>, %1.<Vetype>[0]
     [ w        , ?r ; neon_from_gp<q>  ] dup\t%0.<Vtype>, %<vwcore>1
  }
)

gcc/Changelog

2023-09-20  Andrea Corallo  <andrea.corallo@arm.com>

	* gensupport.cc (convert_syntax): Skip spaces before "cons:"
	in new compact pattern syntax.