Hi Haochen,
on 2023/6/19 09:14, HAO CHEN GUI wrote:
> Hi,
> This patch modifies vsx extract expander and generates mfvsrwz/stxsiwx
> for all platforms when the mode is V4SI and the index of extracted element
> is 1 for BE and 2 for LE. Also this patch adds a insn pattern for mfvsrwz
> which can help eliminate redundant zero extend.
>
> Bootstrapped and tested on powerpc64-linux BE and LE with no regressions.
>
> Thanks
> Gui Haochen
>
>
> ChangeLog
> rs6000: Generate mfvsrwz for all platforms and remove redundant zero extend
>
> mfvsrwz has lower latency than xxextractuw. So it should be generated
Nice, it also has lower latency than vextuw[lr]x.
> even with p9 vector enabled if possible. Also the instruction is
> already zero extended. A combine pattern is needed to eliminate
> redundant zero extend instructions.
>
> gcc/
> PR target/106769
> * config/rs6000/vsx.md (expand vsx_extract_<mode>): Skip calling
> gen_vsx_extract_<mode>_p9 when it can be implemented by
> mfvsrwz/stxsiwx.
> (*vsx_extract_<mode>_di_p9): Not generate the insn when it can
> be generated by mfvsrwz.
> (mfvsrwz): New insn pattern.
> (*vsx_extract_si): Rename to...
> (vsx_extract_si): ..., remove redundant insn condition and
> generate the insn on p9 when it can be implemented by
> mfvsrwz/stxsiwx. Add a dup alternative for simple vector moving.
> Remove reload_completed from split condition as it's unnecessary.
> Remove unnecessary checking from preparation statements. Set
> type and length attributes for each alternative.
>
> gcc/testsuite/
> PR target/106769
> * gcc.target/powerpc/pr106769.h: New.
> * gcc.target/powerpc/pr106769-p8.c: New.
> * gcc.target/powerpc/pr106769-p9.c: New.
>
> diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
> index 0a34ceebeb5..09b0f83db86 100644
> --- a/gcc/config/rs6000/vsx.md
> +++ b/gcc/config/rs6000/vsx.md
> @@ -3728,7 +3728,9 @@ (define_expand "vsx_extract_<mode>"
I noticed that we special case VSX_D for vsx_extract_<mode>, then it
has two special define_insn for special operand 2 (0/1) like:
"define_insn "*vsx_extract_<mode>_0" and "..._1".
I wonder if we can do a similar thing to special case VSX_W, it seems
more clear?
> "VECTOR_MEM_VSX_P (<MODE>mode) && TARGET_DIRECT_MOVE_64BIT"
> {
> /* If we have ISA 3.0, we can do a xxextractuw/vextractu{b,h}. */
> - if (TARGET_P9_VECTOR)
> + if (TARGET_P9_VECTOR
> + && (<MODE>mode != V4SImode
> + || INTVAL (operands[2]) != (BYTES_BIG_ENDIAN ? 1 : 2)))
> {
> emit_insn (gen_vsx_extract_<mode>_p9 (operands[0], operands[1],
> operands[2]));
> @@ -3798,7 +3800,9 @@ (define_insn_and_split "*vsx_extract_<mode>_di_p9"
> (match_operand:VSX_EXTRACT_I 1 "gpc_reg_operand" "v,<VSX_EX>")
> (parallel [(match_operand:QI 2 "const_int_operand" "n,n")]))))
> (clobber (match_scratch:SI 3 "=r,X"))]
> - "VECTOR_MEM_VSX_P (<MODE>mode) && TARGET_VEXTRACTUB"
> + "TARGET_VEXTRACTUB
> + && (<MODE>mode != V4SImode
> + || INTVAL (operands[2]) != (BYTES_BIG_ENDIAN ? 1 : 2))"
> "#"
> "&& reload_completed"
> [(parallel [(set (match_dup 4)
> @@ -3830,58 +3834,67 @@ (define_insn_and_split "*vsx_extract_<mode>_store_p9"
> (set (match_dup 0)
> (match_dup 3))])
>
> -(define_insn_and_split "*vsx_extract_si"
> - [(set (match_operand:SI 0 "nonimmediate_operand" "=r,wa,Z")
> +(define_insn "mfvsrwz"
> + [(set (match_operand:DI 0 "register_operand" "=r")
> + (zero_extend:DI
> + (vec_select:SI
> + (match_operand:V4SI 1 "vsx_register_operand" "wa")
> + (parallel [(match_operand:QI 2 "const_int_operand" "n")]))))
> + (clobber (match_scratch:V4SI 3 "=v"))]
> + "TARGET_DIRECT_MOVE_64BIT
> + && INTVAL (operands[2]) == (BYTES_BIG_ENDIAN ? 1 : 2)"
> + "mfvsrwz %0,%x1"
> + [(set_attr "type" "mfvsr")
> + (set_attr "isa" "p8v")])
> +
> +(define_insn_and_split "vsx_extract_si"
> + [(set (match_operand:SI 0 "nonimmediate_operand" "=r,wa,Z,wa")
> (vec_select:SI
> - (match_operand:V4SI 1 "gpc_reg_operand" "v,v,v")
> - (parallel [(match_operand:QI 2 "const_0_to_3_operand" "n,n,n")])))
> - (clobber (match_scratch:V4SI 3 "=v,v,v"))]
> - "VECTOR_MEM_VSX_P (V4SImode) && TARGET_DIRECT_MOVE_64BIT &&
> !TARGET_P9_VECTOR"
> - "#"
> - "&& reload_completed"
> + (match_operand:V4SI 1 "gpc_reg_operand" "v,v,v,0")
> + (parallel [(match_operand:QI 2 "const_0_to_3_operand" "n,n,n,n")])))
> + (clobber (match_scratch:V4SI 3 "=v,v,v,v"))]
> + "TARGET_DIRECT_MOVE_64BIT
> + && (!TARGET_P9_VECTOR || INTVAL (operands[2]) == (BYTES_BIG_ENDIAN ? 1 :
> 2))"
> +{
> + if (which_alternative == 0)
> + return "mfvsrwz %0,%x1";
> +
> + if (which_alternative == 1)
> + return "xxlor %x0,%x1,%x1";
> +
> + if (which_alternative == 2)
> + return "stxsiwx %x1,%y0";
> +
> + return ASM_COMMENT_START " vec_extract to same register";
> +}
> + "&& INTVAL (operands[2]) != (BYTES_BIG_ENDIAN ? 1 : 2)"
> [(const_int 0)]
> {
> rtx dest = operands[0];
> rtx src = operands[1];
> rtx element = operands[2];
> - rtx vec_tmp = operands[3];
> - int value;
> + rtx vec_tmp;
> +
> + if (GET_CODE (operands[3]) == SCRATCH)
> + vec_tmp = gen_reg_rtx (V4SImode);
> + else
> + vec_tmp = operands[3];
>
> /* Adjust index for LE element ordering, the below minuend 3 is computed by
> GET_MODE_NUNITS (V4SImode) - 1. */
> if (!BYTES_BIG_ENDIAN)
> element = GEN_INT (3 - INTVAL (element));
>
> - /* If the value is in the correct position, we can avoid doing the VSPLT<x>
> - instruction. */
> - value = INTVAL (element);
> - if (value != 1)
> - emit_insn (gen_altivec_vspltw_direct (vec_tmp, src, element));
> - else
> - vec_tmp = src;
> -
> - if (MEM_P (operands[0]))
> - {
> - if (can_create_pseudo_p ())
> - dest = rs6000_force_indexed_or_indirect_mem (dest);
> + emit_insn (gen_altivec_vspltw_direct (vec_tmp, src, element));
>
> - if (TARGET_P8_VECTOR)
> - emit_move_insn (dest, gen_rtx_REG (SImode, REGNO (vec_tmp)));
> - else
> - emit_insn (gen_stfiwx (dest, gen_rtx_REG (DImode, REGNO (vec_tmp))));
> - }
> -
> - else if (TARGET_P8_VECTOR)
> - emit_move_insn (dest, gen_rtx_REG (SImode, REGNO (vec_tmp)));
> - else
> - emit_move_insn (gen_rtx_REG (DImode, REGNO (dest)),
> - gen_rtx_REG (DImode, REGNO (vec_tmp)));
> + int value = BYTES_BIG_ENDIAN ? 1 : 2;
> + emit_insn (gen_vsx_extract_si (dest, vec_tmp, GEN_INT (value)));
>
> DONE;
> }
> - [(set_attr "type" "mfvsr,vecperm,fpstore")
> - (set_attr "length" "8")
> - (set_attr "isa" "*,p8v,*")])
> + [(set_attr "type" "mfvsr,veclogical,fpstore,*")
> + (set_attr "length" "4,4,4,0")
> + (set_attr "isa" "p8v,*,p8v,*")])
>
> (define_insn_and_split "*vsx_extract_<mode>_p8"
> [(set (match_operand:<VEC_base> 0 "nonimmediate_operand" "=r")
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106769-p8.c
> b/gcc/testsuite/gcc.target/powerpc/pr106769-p8.c
> new file mode 100644
> index 00000000000..e7cdbc76298
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106769-p8.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-skip-if "" { powerpc*-*-darwin* } } */
> +/* { dg-require-effective-target powerpc_p8vector_ok } */
> +/* { dg-options "-mdejagnu-cpu=power8 -O2" } */
> +/* { dg-require-effective-target has_arch_ppc64 } */
> +
> +#include "pr106769.h"
> +
> +/* { dg-final { scan-assembler {\mmfvsrwz\M} } } */
> +/* { dg-final { scan-assembler {\mstxsiwx\M} } } */
> +/* { dg-final { scan-assembler-not {\mrldicl\M} } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106769-p9.c
> b/gcc/testsuite/gcc.target/powerpc/pr106769-p9.c
> new file mode 100644
> index 00000000000..d21c7f13382
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106769-p9.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-skip-if "" { powerpc*-*-darwin* } } */
> +/* { dg-require-effective-target powerpc_p9vector_ok } */
> +/* { dg-options "-mdejagnu-cpu=power9 -O2" } */
> +/* { dg-require-effective-target has_arch_ppc64 } */
> +
> +#include "pr106769.h"
> +
> +/* { dg-final { scan-assembler {\mmfvsrwz\M} } } */
> +/* { dg-final { scan-assembler {\mstxsiwx\M} } } */
> +/* { dg-final { scan-assembler-not {\mrldicl\M} } } */
> +/* { dg-final { scan-assembler-not {\mxxextractuw\M} } } */
Nit: scan-assembler-not vextuw[rl]x.
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106769.h
> b/gcc/testsuite/gcc.target/powerpc/pr106769.h
> new file mode 100644
> index 00000000000..1c8c8a024f3
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106769.h
> @@ -0,0 +1,17 @@
> +#include <altivec.h>
> +
> +#ifdef __BIG_ENDIAN__
> +#define LANE 1
> +#else
> +#define LANE 2
> +#endif
> +
> +unsigned int foo1 (vector unsigned int v)
> +{
> + return vec_extract(v, LANE);
> +}
> +
> +void foo2 (vector unsigned int v, unsigned int* p)
> +{
> + *p = vec_extract(v, LANE);
> +}
BR,
Kewen
