On Thu, Jul 10, 2025 at 8:06 PM Daniel Henrique Barboza
<dbarb...@ventanamicro.com> wrote:
>
> This reverts commit 28c12c1f2f50d7f7f1ebfc587c4777ecd50aac5b.
>
> As reported in [1] this commit is breaking Linux vector code, and
> although a simpler reproducer was provided, the fix itself isn't trivial
> due to the amount and the nature of the changes. And we really do not
> want to keep Linux broken while we work on it.
>
> The revert will fix Linux and will give us time to do a proper fix.
>
> [1] https://mail.gnu.org/archive/html/qemu-devel/2025-07/msg02525.html
>
> Signed-off-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
Thanks!
Applied to riscv-to-apply.next
Alistair
> ---
> target/riscv/insn_trans/trans_rvv.c.inc | 323 ++++--------------------
> 1 file changed, 50 insertions(+), 273 deletions(-)
>
> diff --git a/target/riscv/insn_trans/trans_rvv.c.inc
> b/target/riscv/insn_trans/trans_rvv.c.inc
> index 610bf9ff30..71f98fb350 100644
> --- a/target/riscv/insn_trans/trans_rvv.c.inc
> +++ b/target/riscv/insn_trans/trans_rvv.c.inc
> @@ -864,286 +864,32 @@ GEN_VEXT_TRANS(vlm_v, MO_8, vlm_v, ld_us_mask_op,
> ld_us_mask_check)
> GEN_VEXT_TRANS(vsm_v, MO_8, vsm_v, st_us_mask_op, st_us_mask_check)
>
> /*
> - * MAXSZ returns the maximum vector size can be operated in bytes,
> - * which is used in GVEC IR when vl_eq_vlmax flag is set to true
> - * to accelerate vector operation.
> - */
> -static inline uint32_t MAXSZ(DisasContext *s)
> -{
> - int max_sz = s->cfg_ptr->vlenb << 3;
> - return max_sz >> (3 - s->lmul);
> -}
> -
> -static inline uint32_t get_log2(uint32_t a)
> -{
> - uint32_t i = 0;
> - for (; a > 0;) {
> - a >>= 1;
> - i++;
> - }
> - return i;
> -}
> -
> -typedef void gen_tl_ldst(TCGv, TCGv_ptr, tcg_target_long);
> -
> -/*
> - * Simulate the strided load/store main loop:
> - *
> - * for (i = env->vstart; i < env->vl; env->vstart = ++i) {
> - * k = 0;
> - * while (k < nf) {
> - * if (!vm && !vext_elem_mask(v0, i)) {
> - * vext_set_elems_1s(vd, vma, (i + k * max_elems) * esz,
> - * (i + k * max_elems + 1) * esz);
> - * k++;
> - * continue;
> - * }
> - * target_ulong addr = base + stride * i + (k << log2_esz);
> - * ldst(env, adjust_addr(env, addr), i + k * max_elems, vd, ra);
> - * k++;
> - * }
> - * }
> - */
> -static void gen_ldst_stride_main_loop(DisasContext *s, TCGv dest, uint32_t
> rs1,
> - uint32_t rs2, uint32_t vm, uint32_t nf,
> - gen_tl_ldst *ld_fn, gen_tl_ldst *st_fn,
> - bool is_load)
> -{
> - TCGv addr = tcg_temp_new();
> - TCGv base = get_gpr(s, rs1, EXT_NONE);
> - TCGv stride = get_gpr(s, rs2, EXT_NONE);
> -
> - TCGv i = tcg_temp_new();
> - TCGv i_esz = tcg_temp_new();
> - TCGv k = tcg_temp_new();
> - TCGv k_esz = tcg_temp_new();
> - TCGv k_max = tcg_temp_new();
> - TCGv mask = tcg_temp_new();
> - TCGv mask_offs = tcg_temp_new();
> - TCGv mask_offs_64 = tcg_temp_new();
> - TCGv mask_elem = tcg_temp_new();
> - TCGv mask_offs_rem = tcg_temp_new();
> - TCGv vreg = tcg_temp_new();
> - TCGv dest_offs = tcg_temp_new();
> - TCGv stride_offs = tcg_temp_new();
> -
> - uint32_t max_elems = MAXSZ(s) >> s->sew;
> -
> - TCGLabel *start = gen_new_label();
> - TCGLabel *end = gen_new_label();
> - TCGLabel *start_k = gen_new_label();
> - TCGLabel *inc_k = gen_new_label();
> - TCGLabel *end_k = gen_new_label();
> -
> - MemOp atomicity = MO_ATOM_NONE;
> - if (s->sew == 0) {
> - atomicity = MO_ATOM_NONE;
> - } else {
> - atomicity = MO_ATOM_IFALIGN_PAIR;
> - }
> -
> - mark_vs_dirty(s);
> -
> - tcg_gen_addi_tl(mask, (TCGv)tcg_env, vreg_ofs(s, 0));
> -
> - /* Start of outer loop. */
> - tcg_gen_mov_tl(i, cpu_vstart);
> - gen_set_label(start);
> - tcg_gen_brcond_tl(TCG_COND_GE, i, cpu_vl, end);
> - tcg_gen_shli_tl(i_esz, i, s->sew);
> - /* Start of inner loop. */
> - tcg_gen_movi_tl(k, 0);
> - gen_set_label(start_k);
> - tcg_gen_brcond_tl(TCG_COND_GE, k, tcg_constant_tl(nf), end_k);
> - /*
> - * If we are in mask agnostic regime and the operation is not unmasked we
> - * set the inactive elements to 1.
> - */
> - if (!vm && s->vma) {
> - TCGLabel *active_element = gen_new_label();
> - /* (i + k * max_elems) * esz */
> - tcg_gen_shli_tl(mask_offs, k, get_log2(max_elems << s->sew));
> - tcg_gen_add_tl(mask_offs, mask_offs, i_esz);
> -
> - /*
> - * Check whether the i bit of the mask is 0 or 1.
> - *
> - * static inline int vext_elem_mask(void *v0, int index)
> - * {
> - * int idx = index / 64;
> - * int pos = index % 64;
> - * return (((uint64_t *)v0)[idx] >> pos) & 1;
> - * }
> - */
> - tcg_gen_shri_tl(mask_offs_64, mask_offs, 3);
> - tcg_gen_add_tl(mask_offs_64, mask_offs_64, mask);
> - tcg_gen_ld_i64((TCGv_i64)mask_elem, (TCGv_ptr)mask_offs_64, 0);
> - tcg_gen_rem_tl(mask_offs_rem, mask_offs, tcg_constant_tl(8));
> - tcg_gen_shr_tl(mask_elem, mask_elem, mask_offs_rem);
> - tcg_gen_andi_tl(mask_elem, mask_elem, 1);
> - tcg_gen_brcond_tl(TCG_COND_NE, mask_elem, tcg_constant_tl(0),
> - active_element);
> - /*
> - * Set masked-off elements in the destination vector register to 1s.
> - * Store instructions simply skip this bit as memory ops access
> memory
> - * only for active elements.
> - */
> - if (is_load) {
> - tcg_gen_shli_tl(mask_offs, mask_offs, s->sew);
> - tcg_gen_add_tl(mask_offs, mask_offs, dest);
> - st_fn(tcg_constant_tl(-1), (TCGv_ptr)mask_offs, 0);
> - }
> - tcg_gen_br(inc_k);
> - gen_set_label(active_element);
> - }
> - /*
> - * The element is active, calculate the address with stride:
> - * target_ulong addr = base + stride * i + (k << log2_esz);
> - */
> - tcg_gen_mul_tl(stride_offs, stride, i);
> - tcg_gen_shli_tl(k_esz, k, s->sew);
> - tcg_gen_add_tl(stride_offs, stride_offs, k_esz);
> - tcg_gen_add_tl(addr, base, stride_offs);
> - /* Calculate the offset in the dst/src vector register. */
> - tcg_gen_shli_tl(k_max, k, get_log2(max_elems));
> - tcg_gen_add_tl(dest_offs, i, k_max);
> - tcg_gen_shli_tl(dest_offs, dest_offs, s->sew);
> - tcg_gen_add_tl(dest_offs, dest_offs, dest);
> - if (is_load) {
> - tcg_gen_qemu_ld_tl(vreg, addr, s->mem_idx, MO_LE | s->sew |
> atomicity);
> - st_fn((TCGv)vreg, (TCGv_ptr)dest_offs, 0);
> - } else {
> - ld_fn((TCGv)vreg, (TCGv_ptr)dest_offs, 0);
> - tcg_gen_qemu_st_tl(vreg, addr, s->mem_idx, MO_LE | s->sew |
> atomicity);
> - }
> - /*
> - * We don't execute the load/store above if the element was inactive.
> - * We jump instead directly to incrementing k and continuing the loop.
> - */
> - if (!vm && s->vma) {
> - gen_set_label(inc_k);
> - }
> - tcg_gen_addi_tl(k, k, 1);
> - tcg_gen_br(start_k);
> - /* End of the inner loop. */
> - gen_set_label(end_k);
> -
> - tcg_gen_addi_tl(i, i, 1);
> - tcg_gen_mov_tl(cpu_vstart, i);
> - tcg_gen_br(start);
> -
> - /* End of the outer loop. */
> - gen_set_label(end);
> -
> - return;
> -}
> -
> -
> -/*
> - * Set the tail bytes of the strided loads/stores to 1:
> - *
> - * for (k = 0; k < nf; ++k) {
> - * cnt = (k * max_elems + vl) * esz;
> - * tot = (k * max_elems + max_elems) * esz;
> - * for (i = cnt; i < tot; i += esz) {
> - * store_1s(-1, vd[vl+i]);
> - * }
> - * }
> + *** stride load and store
> */
> -static void gen_ldst_stride_tail_loop(DisasContext *s, TCGv dest, uint32_t
> nf,
> - gen_tl_ldst *st_fn)
> -{
> - TCGv i = tcg_temp_new();
> - TCGv k = tcg_temp_new();
> - TCGv tail_cnt = tcg_temp_new();
> - TCGv tail_tot = tcg_temp_new();
> - TCGv tail_addr = tcg_temp_new();
> -
> - TCGLabel *start = gen_new_label();
> - TCGLabel *end = gen_new_label();
> - TCGLabel *start_i = gen_new_label();
> - TCGLabel *end_i = gen_new_label();
> -
> - uint32_t max_elems_b = MAXSZ(s);
> - uint32_t esz = 1 << s->sew;
> -
> - /* Start of the outer loop. */
> - tcg_gen_movi_tl(k, 0);
> - tcg_gen_shli_tl(tail_cnt, cpu_vl, s->sew);
> - tcg_gen_movi_tl(tail_tot, max_elems_b);
> - tcg_gen_add_tl(tail_addr, dest, tail_cnt);
> - gen_set_label(start);
> - tcg_gen_brcond_tl(TCG_COND_GE, k, tcg_constant_tl(nf), end);
> - /* Start of the inner loop. */
> - tcg_gen_mov_tl(i, tail_cnt);
> - gen_set_label(start_i);
> - tcg_gen_brcond_tl(TCG_COND_GE, i, tail_tot, end_i);
> - /* store_1s(-1, vd[vl+i]); */
> - st_fn(tcg_constant_tl(-1), (TCGv_ptr)tail_addr, 0);
> - tcg_gen_addi_tl(tail_addr, tail_addr, esz);
> - tcg_gen_addi_tl(i, i, esz);
> - tcg_gen_br(start_i);
> - /* End of the inner loop. */
> - gen_set_label(end_i);
> - /* Update the counts */
> - tcg_gen_addi_tl(tail_cnt, tail_cnt, max_elems_b);
> - tcg_gen_addi_tl(tail_tot, tail_cnt, max_elems_b);
> - tcg_gen_addi_tl(k, k, 1);
> - tcg_gen_br(start);
> - /* End of the outer loop. */
> - gen_set_label(end);
> -
> - return;
> -}
> +typedef void gen_helper_ldst_stride(TCGv_ptr, TCGv_ptr, TCGv,
> + TCGv, TCGv_env, TCGv_i32);
>
> static bool ldst_stride_trans(uint32_t vd, uint32_t rs1, uint32_t rs2,
> - uint32_t data, DisasContext *s, bool is_load)
> + uint32_t data, gen_helper_ldst_stride *fn,
> + DisasContext *s)
> {
> - if (!s->vstart_eq_zero) {
> - return false;
> - }
> -
> - TCGv dest = tcg_temp_new();
> -
> - uint32_t nf = FIELD_EX32(data, VDATA, NF);
> - uint32_t vm = FIELD_EX32(data, VDATA, VM);
> -
> - /* Destination register and mask register */
> - tcg_gen_addi_tl(dest, (TCGv)tcg_env, vreg_ofs(s, vd));
> -
> - /*
> - * Select the appropriate load/tore to retrieve data from the vector
> - * register given a specific sew.
> - */
> - static gen_tl_ldst * const ld_fns[4] = {
> - tcg_gen_ld8u_tl, tcg_gen_ld16u_tl,
> - tcg_gen_ld32u_tl, tcg_gen_ld_tl
> - };
> -
> - static gen_tl_ldst * const st_fns[4] = {
> - tcg_gen_st8_tl, tcg_gen_st16_tl,
> - tcg_gen_st32_tl, tcg_gen_st_tl
> - };
> + TCGv_ptr dest, mask;
> + TCGv base, stride;
> + TCGv_i32 desc;
>
> - gen_tl_ldst *ld_fn = ld_fns[s->sew];
> - gen_tl_ldst *st_fn = st_fns[s->sew];
> + dest = tcg_temp_new_ptr();
> + mask = tcg_temp_new_ptr();
> + base = get_gpr(s, rs1, EXT_NONE);
> + stride = get_gpr(s, rs2, EXT_NONE);
> + desc = tcg_constant_i32(simd_desc(s->cfg_ptr->vlenb,
> + s->cfg_ptr->vlenb, data));
>
> - if (ld_fn == NULL || st_fn == NULL) {
> - return false;
> - }
> + tcg_gen_addi_ptr(dest, tcg_env, vreg_ofs(s, vd));
> + tcg_gen_addi_ptr(mask, tcg_env, vreg_ofs(s, 0));
>
> mark_vs_dirty(s);
>
> - gen_ldst_stride_main_loop(s, dest, rs1, rs2, vm, nf, ld_fn, st_fn,
> is_load);
> -
> - tcg_gen_movi_tl(cpu_vstart, 0);
> -
> - /*
> - * Set the tail bytes to 1 if tail agnostic:
> - */
> - if (s->vta != 0 && is_load) {
> - gen_ldst_stride_tail_loop(s, dest, nf, st_fn);
> - }
> + fn(dest, mask, base, stride, tcg_env, desc);
>
> finalize_rvv_inst(s);
> return true;
> @@ -1152,6 +898,16 @@ static bool ldst_stride_trans(uint32_t vd, uint32_t
> rs1, uint32_t rs2,
> static bool ld_stride_op(DisasContext *s, arg_rnfvm *a, uint8_t eew)
> {
> uint32_t data = 0;
> + gen_helper_ldst_stride *fn;
> + static gen_helper_ldst_stride * const fns[4] = {
> + gen_helper_vlse8_v, gen_helper_vlse16_v,
> + gen_helper_vlse32_v, gen_helper_vlse64_v
> + };
> +
> + fn = fns[eew];
> + if (fn == NULL) {
> + return false;
> + }
>
> uint8_t emul = vext_get_emul(s, eew);
> data = FIELD_DP32(data, VDATA, VM, a->vm);
> @@ -1159,7 +915,7 @@ static bool ld_stride_op(DisasContext *s, arg_rnfvm *a,
> uint8_t eew)
> data = FIELD_DP32(data, VDATA, NF, a->nf);
> data = FIELD_DP32(data, VDATA, VTA, s->vta);
> data = FIELD_DP32(data, VDATA, VMA, s->vma);
> - return ldst_stride_trans(a->rd, a->rs1, a->rs2, data, s, true);
> + return ldst_stride_trans(a->rd, a->rs1, a->rs2, data, fn, s);
> }
>
> static bool ld_stride_check(DisasContext *s, arg_rnfvm* a, uint8_t eew)
> @@ -1177,13 +933,23 @@ GEN_VEXT_TRANS(vlse64_v, MO_64, rnfvm, ld_stride_op,
> ld_stride_check)
> static bool st_stride_op(DisasContext *s, arg_rnfvm *a, uint8_t eew)
> {
> uint32_t data = 0;
> + gen_helper_ldst_stride *fn;
> + static gen_helper_ldst_stride * const fns[4] = {
> + /* masked stride store */
> + gen_helper_vsse8_v, gen_helper_vsse16_v,
> + gen_helper_vsse32_v, gen_helper_vsse64_v
> + };
>
> uint8_t emul = vext_get_emul(s, eew);
> data = FIELD_DP32(data, VDATA, VM, a->vm);
> data = FIELD_DP32(data, VDATA, LMUL, emul);
> data = FIELD_DP32(data, VDATA, NF, a->nf);
> + fn = fns[eew];
> + if (fn == NULL) {
> + return false;
> + }
>
> - return ldst_stride_trans(a->rd, a->rs1, a->rs2, data, s, false);
> + return ldst_stride_trans(a->rd, a->rs1, a->rs2, data, fn, s);
> }
>
> static bool st_stride_check(DisasContext *s, arg_rnfvm* a, uint8_t eew)
> @@ -1534,6 +1300,17 @@ GEN_LDST_WHOLE_TRANS(vs8r_v, int8_t, 8, false)
> *** Vector Integer Arithmetic Instructions
> */
>
> +/*
> + * MAXSZ returns the maximum vector size can be operated in bytes,
> + * which is used in GVEC IR when vl_eq_vlmax flag is set to true
> + * to accelerate vector operation.
> + */
> +static inline uint32_t MAXSZ(DisasContext *s)
> +{
> + int max_sz = s->cfg_ptr->vlenb * 8;
> + return max_sz >> (3 - s->lmul);
> +}
> +
> static bool opivv_check(DisasContext *s, arg_rmrr *a)
> {
> return require_rvv(s) &&
> --
> 2.50.0
>
>
