Hi kito, Per off-line sync with Juzhe, I can help the rest part of this PATCH, will try the suggested approach and keep you posted.
Pan -----Original Message----- From: Gcc-patches <gcc-patches-bounces+pan2.li=intel....@gcc.gnu.org> On Behalf Of Kito Cheng via Gcc-patches Sent: Saturday, May 13, 2023 11:14 AM To: juzhe.zh...@rivai.ai Cc: gcc-patches@gcc.gnu.org; pal...@dabbelt.com; jeffreya...@gmail.com; rdapp....@gmail.com Subject: Re: [PATCH] RISC-V: Optimize vsetvl AVL for VLS VLMAX auto-vectorization Hmmm here is alternative approach for this: diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc index b8dc333f54e1..c88056024e7d 100644 --- a/gcc/config/riscv/riscv-v.cc +++ b/gcc/config/riscv/riscv-v.cc @@ -50,6 +50,21 @@ using namespace riscv_vector; namespace riscv_vector { +/* Return true if vlmax is constant value instead and can be used + in vsetivli. */ +static bool +const_vlmax_p (machine_mode mode) +{ + poly_uint64 nunits = GET_MODE_NUNITS (mode); + + /* Only allowed in VLS-VLMAX mode. */ if (!nunits.is_constant ()) + return false; + + /* vsetivli can only hold 0~31. */ + return (IN_RANGE (nunits.to_constant (), 0, 31)); } + template <int MAX_OPERANDS> class insn_expander { public: @@ -101,15 +116,26 @@ public: void set_len_and_policy (rtx len, bool force_vlmax = false) { - bool vlmax_p = force_vlmax; + bool vlmax_p = force_vlmax || !len; gcc_assert (has_dest); - if (!len) + if (vlmax_p) { - vlmax_p = true; - len = gen_reg_rtx (Pmode); - emit_vlmax_vsetvl (dest_mode, len); - } + if (const_vlmax_p (dest_mode)) + { + /* Optimize VLS-VLMAX code gen, we can use vsetivli instead of + vsetvli to obtain the value of vlmax. */ + poly_uint64 nunits = GET_MODE_NUNITS (dest_mode); + len = gen_int_mode (nunits, Pmode); + /* It has become NONVLMAX now. */ + vlmax_p = false; + } + else if (!len) + { + len = gen_reg_rtx (Pmode); + emit_vlmax_vsetvl (dest_mode, len); + } + } add_input_operand (len, Pmode); -- On Sat, May 13, 2023 at 10:09 AM <juzhe.zh...@rivai.ai> wrote: > > From: Juzhe-Zhong <juzhe.zh...@rivai.ai> > > This patch is optimizing the AVL for VLS auto-vectorzation. > > Consider such case: > > typedef int8_t vnx2qi __attribute__ ((vector_size (2))); > > __attribute__ ((noipa)) void > f_vnx2qi (int8_t a, int8_t b, int8_t *out) { > vnx2qi v = {a, b}; > *(vnx2qi *) out = v; > } > > Before this patch: > > f_vnx2qi: > vsetvli a5,zero,e8,mf8,ta,ma > vmv.v.x v1,a0 > vslide1down.vx v1,v1,a1 > vse8.v v1,0(a2) > ret > > After this patch: > > f_vnx2qi: > vsetivli zero,2,e8,mf8,ta,ma > vmv.v.x v1,a0 > vslide1down.vx v1,v1,a1 > vse8.v v1,0(a2) > ret > > gcc/ChangeLog: > > * config/riscv/riscv-protos.h (emit_vlmax_vsetvl): Change argument > type. > * config/riscv/riscv-v.cc (emit_vlmax_vsetvl): Optimize AVL for vlmax > VLS. > (emit_vlmax_reg_op): Ditto. > * config/riscv/vector.md: Adapt argument. > > gcc/testsuite/ChangeLog: > > * gcc.target/riscv/rvv/base/vf_avl-1.c: New test. > > --- > gcc/config/riscv/riscv-protos.h | 2 +- > gcc/config/riscv/riscv-v.cc | 25 +++++++++++++++---- > gcc/config/riscv/vector.md | 4 +-- > .../gcc.target/riscv/rvv/base/vf_avl-1.c | 15 +++++++++++ > 4 files changed, 38 insertions(+), 8 deletions(-) create mode 100644 > gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-1.c > > diff --git a/gcc/config/riscv/riscv-protos.h > b/gcc/config/riscv/riscv-protos.h index bc71f9cbbba..90934d43430 > 100644 > --- a/gcc/config/riscv/riscv-protos.h > +++ b/gcc/config/riscv/riscv-protos.h > @@ -164,7 +164,7 @@ bool check_builtin_call (location_t, vec<location_t>, > unsigned int, > tree, unsigned int, tree *); bool > const_vec_all_same_in_range_p (rtx, HOST_WIDE_INT, HOST_WIDE_INT); > bool legitimize_move (rtx, rtx, machine_mode); -void emit_vlmax_vsetvl > (machine_mode, rtx); > +void emit_vlmax_vsetvl (machine_mode, rtx *); > void emit_hard_vlmax_vsetvl (machine_mode, rtx); void emit_vlmax_op > (unsigned, rtx, rtx, machine_mode); void emit_vlmax_reg_op (unsigned, > rtx, rtx, rtx, machine_mode); diff --git a/gcc/config/riscv/riscv-v.cc > b/gcc/config/riscv/riscv-v.cc index d844c305320..382cc4b6311 100644 > --- a/gcc/config/riscv/riscv-v.cc > +++ b/gcc/config/riscv/riscv-v.cc > @@ -120,7 +120,9 @@ public: > { > vlmax_p = true; > len = gen_reg_rtx (Pmode); > - emit_vlmax_vsetvl (dest_mode, len); > + emit_vlmax_vsetvl (dest_mode, &len); > + if (CONST_INT_P (len)) > + vlmax_p = false; > } > > add_input_operand (len, Pmode); > @@ -183,16 +185,29 @@ emit_hard_vlmax_vsetvl (machine_mode vmode, rtx > vl) } > > void > -emit_vlmax_vsetvl (machine_mode vmode, rtx vl) > +emit_vlmax_vsetvl (machine_mode vmode, rtx *vl) > { > unsigned int sew = get_sew (vmode); > enum vlmul_type vlmul = get_vlmul (vmode); > unsigned int ratio = calculate_ratio (sew, vlmul); > > + /* For VLS VLMAX auto-vectorization, we change > + VL into const_int value of VF so that we > + will emit "vsetivli zero, CONST_INT" instead of > + "vsetvli a5, zero". > + > + TODO: Support VLS min-length in the future. */ > + poly_uint64 nunits = GET_MODE_NUNITS (vmode); if > + (nunits.is_constant () && IN_RANGE (nunits.to_constant (), 0, 31)) > + { > + *vl = gen_int_mode (nunits, Pmode); > + return; > + } > + > if (!optimize) > - emit_hard_vlmax_vsetvl (vmode, vl); > + emit_hard_vlmax_vsetvl (vmode, *vl); > else > - emit_insn (gen_vlmax_avl (Pmode, vl, gen_int_mode (ratio, Pmode))); > + emit_insn (gen_vlmax_avl (Pmode, *vl, gen_int_mode (ratio, > + Pmode))); > } > > /* Calculate SEW/LMUL ratio. */ > @@ -323,7 +338,7 @@ emit_vlmax_reg_op (unsigned icode, rtx dest, rtx src, rtx > len, > machine_mode mask_mode) { > emit_pred_op (icode, NULL_RTX, dest, src, len, mask_mode, > - /* Force VLMAX */ true); > + /* Force VLMAX */ CONST_INT_P (len) ? false : true); > } > > void > diff --git a/gcc/config/riscv/vector.md b/gcc/config/riscv/vector.md > index 328fce8d632..b02ecf92c00 100644 > --- a/gcc/config/riscv/vector.md > +++ b/gcc/config/riscv/vector.md > @@ -720,7 +720,7 @@ > emit_insn (gen_rtx_SET (operands[0], operands[1])); > else > { > - riscv_vector::emit_vlmax_vsetvl (<V_FRACT:MODE>mode, operands[2]); > + riscv_vector::emit_vlmax_vsetvl (<V_FRACT:MODE>mode, > + &operands[2]); > riscv_vector::emit_vlmax_reg_op (code_for_pred_mov > (<V_FRACT:MODE>mode), > operands[0], operands[1], operands[2], > <VM>mode); @@ -741,7 +741,7 @@ > emit_insn (gen_rtx_SET (operands[0], operands[1])); > else > { > - riscv_vector::emit_vlmax_vsetvl (<VB:MODE>mode, operands[2]); > + riscv_vector::emit_vlmax_vsetvl (<VB:MODE>mode, &operands[2]); > riscv_vector::emit_vlmax_reg_op (code_for_pred_mov (<VB:MODE>mode), > operands[0], operands[1], operands[2], > <VB:MODE>mode); diff --git > a/gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-1.c > b/gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-1.c > new file mode 100644 > index 00000000000..11adf6bc611 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-1.c > @@ -0,0 +1,15 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O3 -march=rv32gcv -mabi=ilp32d --param > +riscv-autovec-preference=fixed-vlmax" } */ > + > +#include <stdint-gcc.h> > + > +typedef int8_t vnx2qi __attribute__ ((vector_size (2))); > + > +__attribute__ ((noipa)) void > +f_vnx2qi (int8_t a, int8_t b, int8_t *out) { > + vnx2qi v = {a, b}; > + *(vnx2qi *) out = v; > +} > + > +/* { dg-final { scan-assembler-times > +{vsetivli\s+zero,\s*2,\s*e8,\s*mf8,\s*t[au],\s*m[au]} 1 } } */ > -- > 2.36.1 >