https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87555
--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Richard Biener from comment #1)
> The complication is that the define_insn looks like
>
> (define_insn "*fma_fmaddsub_<mode>"
> [(set (match_operand:VF_128_256 0 "register_operand" "=v,v,v,x,x")
> (unspec:VF_128_256
> [(match_operand:VF_128_256 1 "nonimmediate_operand" "%0,0,v,x,x")
> (match_operand:VF_128_256 2 "nonimmediate_operand" "vm,v,vm,x,m")
> (match_operand:VF_128_256 3 "nonimmediate_operand" "v,vm,0,xm,x")]
> UNSPEC_FMADDSUB))]
> "TARGET_FMA || TARGET_FMA4"
> "@
> vfmaddsub132<ssemodesuffix>\t{%2, %3, %0|%0, %3, %2}
> vfmaddsub213<ssemodesuffix>\t{%3, %2, %0|%0, %2, %3}
> vfmaddsub231<ssemodesuffix>\t{%2, %1, %0|%0, %1, %2}
> vfmaddsub<ssemodesuffix>\t{%3, %2, %1, %0|%0, %1, %2, %3}
> vfmaddsub<ssemodesuffix>\t{%3, %2, %1, %0|%0, %1, %2, %3}"
>
> so it can handle the {132,213,231} variants without much duplication from a
> single pattern. But it seems this cannot prevail when we open-code the
> operation. Likewise handling multiple modes with the VF_128_256 iterator
> becomes difficult since the addsub requires either a vec_merge (as in the
> addsub patterns) with a constant selector specific to the mode (unless we
> can provide a large one that is implicitely truncated) or a vector constant
> when using the (vec_select (vec_concat ...)) form. So the above would
> split into 12 somewhat repetitive patterns.
we already has *fma_fmadd_<mode> with one pattern
(define_insn "*fma_fmadd_<mode>"
[(set (match_operand:FMAMODE 0 "register_operand" "=v,v,v,x,x")
(fma:FMAMODE
(match_operand:FMAMODE 1 "nonimmediate_operand" "%0,0,v,x,x")
(match_operand:FMAMODE 2 "nonimmediate_operand" "vm,v,vm,x,m")
(match_operand:FMAMODE 3 "nonimmediate_operand" "v,vm,0,xm,x")))]
"TARGET_FMA || TARGET_FMA4"
"@
vfmadd132<ssemodesuffix>\t{%2, %3, %0|%0, %3, %2}
vfmadd213<ssemodesuffix>\t{%3, %2, %0|%0, %2, %3}
vfmadd231<ssemodesuffix>\t{%2, %1, %0|%0, %1, %2}
vfmadd<ssemodesuffix>\t{%3, %2, %1, %0|%0, %1, %2, %3}
vfmadd<ssemodesuffix>\t{%3, %2, %1, %0|%0, %1, %2, %3}"
[(set_attr "isa" "fma,fma,fma,fma4,fma4")
(set_attr "type" "ssemuladd")
(set_attr "mode" "<MODE>")])
So can't it be changed to
(define_mode_attr addsub_cst [(V4DF "5") (V2DF "1")
(V4SF "5") (V8SF "85")])
(define_insn "*fma_fmaddsub_<mode>"
[(set (match_operand:VF_128_256 0 "register_operand" "=v,v,v,x,x")
(vec_merge:VF_128_256
(fma:VF_128_256
(match_operand:VF_128_256 1 "nonimmediate_operand" "%0,0,v,x,x")
(match_operand:VF_128_256 2 "nonimmediate_operand" "vm,v,vm,x,m")
(match_operand:VF_128_256 3 "nonimmediate_operand" "v,vm,0,xm,x"))
(fma:VF_128_256
(match_dup 1)
(match_dup 2)
(neg:VF_128_256 (match_dup 3))
(const_int <addsub_cst>)))]
"TARGET_FMA || TARGET_FMA4"
"@
vfmaddsub132<ssemodesuffix>\t{%2, %3, %0|%0, %3, %2}
vfmaddsub213<ssemodesuffix>\t{%3, %2, %0|%0, %2, %3}
vfmaddsub231<ssemodesuffix>\t{%2, %1, %0|%0, %1, %2}
vfmaddsub<ssemodesuffix>\t{%3, %2, %1, %0|%0, %1, %2, %3}
vfmaddsub<ssemodesuffix>\t{%3, %2, %1, %0|%0, %1, %2, %3}"
[(set_attr "isa" "fma,fma,fma,fma4,fma4")
(set_attr "type" "ssemuladd")
(set_attr "mode" "<MODE>")])
