On Fri, Jun 16, 2023 at 4:12 AM liuhongt <hongtao....@intel.com> wrote:
>
> packuswb/packusdw does unsigned saturation for signed source, but rtl
> us_truncate means does unsigned saturation for unsigned source.
> So for value -1, packuswb will produce 0, but us_truncate produces
> 255. The patch reimplement those related patterns and functions with
> UNSPEC_US_TRUNCATE instead of us_truncate.
>
> The patch will fix below testcase which failed after
> g:921b841350c4fc298d09f6c5674663e0f4208610 added constant-folding for
> US_TRUNCATE
>
> FAIL: gcc.target/i386/avx-vpackuswb-1.c execution test
> FAIL: gcc.target/i386/avx2-vpackusdw-2.c execution test
> FAIL: gcc.target/i386/avx2-vpackuswb-2.c execution test
> FAIL: gcc.target/i386/sse2-packuswb-1.c execution test
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu.
> Ok for trunk?
Please proofread the ChangeLog entries and comments and fix confusion
with truncation / saturation in comments.
OK with the above change.
Thanks,
Uros.
>
> gcc/ChangeLog:
>
> PR target/110235
> * config/i386/i386-expand.cc (ix86_split_mmx_pack): Use
> UNSPEC_US_TRUNCATE instead of original us_truncate for
> packusdw/packuswb.
> * config/i386/mmx.md (mmx_pack<s_trunsuffix>swb): Splitted to
> below 2 new patterns.
Just say: ...: Substitute with ...
> (mmx_packsswb): New reload_completed define_insn_and_split.
...: ... this and ...
> (mmx_packuswb): Ditto.
...: ... this.
> (mmx_packusdw): Use UNSPEC_US_TRUNCATE instead of original
> us_truncate.
> (s_trunsuffix): Removed.
...: Remove code iterator.
> (any_s_truncate): Removed.
...: Ditto.
> * config/i386/sse.md (<sse2_avx2>_packuswb<mask_name>): Use
> UNSPEC_US_TRUNCATE instead of original us_truncate.
> (<sse4_1_avx2>_packusdw<mask_name>): Ditto.
> * config/i386/i386.md (UNSPEC_US_TRUNCATE): New unspec_c_enum.
> ---
> gcc/config/i386/i386-expand.cc | 20 ++++++++++++----
> gcc/config/i386/i386.md | 4 ++++
> gcc/config/i386/mmx.md | 43 ++++++++++++++++++++++------------
> gcc/config/i386/sse.md | 20 ++++++++--------
> 4 files changed, 57 insertions(+), 30 deletions(-)
>
> diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
> index def060ab562..35e2740f9b6 100644
> --- a/gcc/config/i386/i386-expand.cc
> +++ b/gcc/config/i386/i386-expand.cc
> @@ -1019,6 +1019,7 @@ ix86_split_mmx_pack (rtx operands[], enum rtx_code code)
> rtx op0 = operands[0];
> rtx op1 = operands[1];
> rtx op2 = operands[2];
> + rtx src;
>
> machine_mode dmode = GET_MODE (op0);
> machine_mode smode = GET_MODE (op1);
> @@ -1042,11 +1043,20 @@ ix86_split_mmx_pack (rtx operands[], enum rtx_code
> code)
> op1 = lowpart_subreg (sse_smode, op1, GET_MODE (op1));
> op2 = lowpart_subreg (sse_smode, op2, GET_MODE (op2));
>
> - op1 = gen_rtx_fmt_e (code, sse_half_dmode, op1);
> - op2 = gen_rtx_fmt_e (code, sse_half_dmode, op2);
> - rtx insn = gen_rtx_SET (dest, gen_rtx_VEC_CONCAT (sse_dmode,
> - op1, op2));
> - emit_insn (insn);
> + /* For packusdw/packuswb, it does unsigned saturation for
> + signed source which is different for rtl US_TRUNCATE. */
paskusdw/packuswb does unsigned saturation of a signed source which is
different from generic us_truncate RTX.
> + if (code == US_TRUNCATE)
> + src = gen_rtx_UNSPEC (sse_dmode,
> + gen_rtvec (2, op1, op2),
> + UNSPEC_US_TRUNCATE);
> + else
> + {
> + op1 = gen_rtx_fmt_e (code, sse_half_dmode, op1);
> + op2 = gen_rtx_fmt_e (code, sse_half_dmode, op2);
> + src = gen_rtx_VEC_CONCAT (sse_dmode, op1, op2);
> + }
> +
> + emit_move_insn (dest, src);
>
> ix86_move_vector_high_sse_to_mmx (op0);
> }
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index 0929115ed4d..070a84d8af9 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -129,6 +129,10 @@ (define_c_enum "unspec" [
> UNSPEC_RSQRT
> UNSPEC_PSADBW
>
> + ;; US_TRUNCATE this is different from rtl us_truncate,
> + ;; it does unsigned truncation for signed source.
Different from generic us_truncate RTX as it does unsigned saturation
of signed source.
> + UNSPEC_US_TRUNCATE
> +
> ;; For AVX/AVX512F support
> UNSPEC_SCALEF
> UNSPEC_PCMP
> diff --git a/gcc/config/i386/mmx.md b/gcc/config/i386/mmx.md
> index 6fbe3909c8b..315eb4193c4 100644
> --- a/gcc/config/i386/mmx.md
> +++ b/gcc/config/i386/mmx.md
> @@ -3337,27 +3337,41 @@ (define_split
> ;;
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> -;; Used in signed and unsigned truncations with saturation.
> -(define_code_iterator any_s_truncate [ss_truncate us_truncate])
> -;; Instruction suffix for truncations with saturation.
> -(define_code_attr s_trunsuffix [(ss_truncate "s") (us_truncate "u")])
> -
> -(define_insn_and_split "mmx_pack<s_trunsuffix>swb"
> +(define_insn_and_split "mmx_packsswb"
> [(set (match_operand:V8QI 0 "register_operand" "=y,x,Yw")
> (vec_concat:V8QI
> - (any_s_truncate:V4QI
> + (ss_truncate:V4QI
> (match_operand:V4HI 1 "register_operand" "0,0,Yw"))
> - (any_s_truncate:V4QI
> + (ss_truncate:V4QI
> (match_operand:V4HI 2 "register_mmxmem_operand" "ym,x,Yw"))))]
> "TARGET_MMX || TARGET_MMX_WITH_SSE"
> "@
> - pack<s_trunsuffix>swb\t{%2, %0|%0, %2}
> + packsswb\t{%2, %0|%0, %2}
> + #
> + #"
> + "&& reload_completed
> + && SSE_REGNO_P (REGNO (operands[0]))"
> + [(const_int 0)]
> + "ix86_split_mmx_pack (operands, SS_TRUNCATE); DONE;"
> + [(set_attr "mmx_isa" "native,sse_noavx,avx")
> + (set_attr "type" "mmxshft,sselog,sselog")
> + (set_attr "mode" "DI,TI,TI")])
> +
This instruction does unsigned saturation of signed source and is
different from generic us_truncate RTX.
> +(define_insn_and_split "mmx_packuswb"
> + [(set (match_operand:V8QI 0 "register_operand" "=y,x,Yw")
> + (unspec:V8QI
> + [(match_operand:V4HI 1 "register_operand" "0,0,Yw")
> + (match_operand:V4HI 2 "register_mmxmem_operand" "ym,x,Yw")]
> + UNSPEC_US_TRUNCATE))]
> + "TARGET_MMX || TARGET_MMX_WITH_SSE"
> + "@
> + packuswb\t{%2, %0|%0, %2}
> #
> #"
> "&& reload_completed
> && SSE_REGNO_P (REGNO (operands[0]))"
> [(const_int 0)]
> - "ix86_split_mmx_pack (operands, <any_s_truncate:CODE>); DONE;"
> + "ix86_split_mmx_pack (operands, US_TRUNCATE); DONE;"
> [(set_attr "mmx_isa" "native,sse_noavx,avx")
> (set_attr "type" "mmxshft,sselog,sselog")
> (set_attr "mode" "DI,TI,TI")])
> @@ -3384,11 +3398,10 @@ (define_insn_and_split "mmx_packssdw"
>
> (define_insn_and_split "mmx_packusdw"
> [(set (match_operand:V4HI 0 "register_operand" "=Yr,*x,Yw")
> - (vec_concat:V4HI
> - (us_truncate:V2HI
> - (match_operand:V2SI 1 "register_operand" "0,0,Yw"))
> - (us_truncate:V2HI
> - (match_operand:V2SI 2 "register_operand" "Yr,*x,Yw"))))]
> + (unspec:V4HI
> + [(match_operand:V2SI 1 "register_operand" "0,0,Yw")
> + (match_operand:V2SI 2 "register_operand" "Yr,*x,Yw")]
> + UNSPEC_US_TRUNCATE))]
> "TARGET_SSE4_1 && TARGET_MMX_WITH_SSE"
> "#"
> "&& reload_completed"
> diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
> index 7d4b4ec8df5..83e3f534fd2 100644
> --- a/gcc/config/i386/sse.md
> +++ b/gcc/config/i386/sse.md
> @@ -17796,13 +17796,14 @@ (define_insn "<sse2_avx2>_packssdw<mask_name>"
> (set_attr "prefix" "orig,<mask_prefix>")
> (set_attr "mode" "<sseinsnmode>")])
>
> +;; This is different from rtl unsigned saturation, the instruction does
> +;; unsigned saturation for signed value.
This instruction does unsigned saturation of signed source and is
different from generic us_truncate RTX.
> (define_insn "<sse2_avx2>_packuswb<mask_name>"
> [(set (match_operand:VI1_AVX512 0 "register_operand" "=x,<v_Yw>")
> - (vec_concat:VI1_AVX512
> - (us_truncate:<ssehalfvecmode>
> - (match_operand:<sseunpackmode> 1 "register_operand" "0,<v_Yw>"))
> - (us_truncate:<ssehalfvecmode>
> - (match_operand:<sseunpackmode> 2 "vector_operand"
> "xBm,<v_Yw>m"))))]
> + (unspec:VI1_AVX512
> + [(match_operand:<sseunpackmode> 1 "register_operand" "0,<v_Yw>")
> + (match_operand:<sseunpackmode> 2 "vector_operand" "xBm,<v_Yw>m")]
> + UNSPEC_US_TRUNCATE))]
> "TARGET_SSE2 && <mask_mode512bit_condition> && <mask_avx512bw_condition>"
> "@
> packuswb\t{%2, %0|%0, %2}
> @@ -21889,11 +21890,10 @@ (define_insn "<sse4_1_avx2>_mpsadbw"
>
> (define_insn "<sse4_1_avx2>_packusdw<mask_name>"
> [(set (match_operand:VI2_AVX2 0 "register_operand" "=Yr,*x,<v_Yw>")
> - (vec_concat:VI2_AVX2
> - (us_truncate:<ssehalfvecmode>
> - (match_operand:<sseunpackmode> 1 "register_operand" "0,0,<v_Yw>"))
> - (us_truncate:<ssehalfvecmode>
> - (match_operand:<sseunpackmode> 2 "vector_operand"
> "YrBm,*xBm,<v_Yw>m"))))]
> + (unspec:VI2_AVX2
> + [(match_operand:<sseunpackmode> 1 "register_operand" "0,0,<v_Yw>")
> + (match_operand:<sseunpackmode> 2 "vector_operand"
> "YrBm,*xBm,<v_Yw>m")]
> + UNSPEC_US_TRUNCATE))]
> "TARGET_SSE4_1 && <mask_mode512bit_condition> && <mask_avx512bw_condition>"
> "@
> packusdw\t{%2, %0|%0, %2}
> --
> 2.39.1.388.g2fc9e9ca3c
>
