Recently, when I was writing a RISCV test, I found that when VL is set to 0, the instruction should be nop, but when I tested it, I found that QEMU will treat all elements as tail elements, and in the case of VTA=1, write all elements to 1.
After troubleshooting, it was found that the vext_vx_rm_1 function was called in the vext_vx_rm_2, and then the vext_set_elems_1s function was called to process the tail element, but only VSTART >= vl was checked in the vext_vx_rm_1 function, which caused the tail element to still be processed even if it was returned in advance. So I've made the following change: Put VSTART_CHECK_EARLY_EXIT(env) at the beginning of the vext_vx_rm_2 function, so that the VSTART register is checked correctly. Fixes: df4252b2ec ("target/riscv/vector_helpers: do early exit when vstart >= vl") Signed-off-by: Chao Liu <lc00...@tecorigin.com> Reviewed-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com> --- target/riscv/vector_helper.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c index 217d2f6..67b3baf 100644 --- a/target/riscv/vector_helper.c +++ b/target/riscv/vector_helper.c @@ -2175,8 +2175,6 @@ vext_vv_rm_1(void *vd, void *v0, void *vs1, void *vs2, uint32_t vl, uint32_t vm, int vxrm, opivv2_rm_fn *fn, uint32_t vma, uint32_t esz) { - VSTART_CHECK_EARLY_EXIT(env, vl); - for (uint32_t i = env->vstart; i < vl; i++) { if (!vm && !vext_elem_mask(v0, i)) { /* set masked-off elements to 1s */ @@ -2200,6 +2198,8 @@ vext_vv_rm_2(void *vd, void *v0, void *vs1, void *vs2, uint32_t vta = vext_vta(desc); uint32_t vma = vext_vma(desc); + VSTART_CHECK_EARLY_EXIT(env, vl); + switch (env->vxrm) { case 0: /* rnu */ vext_vv_rm_1(vd, v0, vs1, vs2, @@ -2302,8 +2302,6 @@ vext_vx_rm_1(void *vd, void *v0, target_long s1, void *vs2, uint32_t vl, uint32_t vm, int vxrm, opivx2_rm_fn *fn, uint32_t vma, uint32_t esz) { - VSTART_CHECK_EARLY_EXIT(env, vl); - for (uint32_t i = env->vstart; i < vl; i++) { if (!vm && !vext_elem_mask(v0, i)) { /* set masked-off elements to 1s */ @@ -2327,6 +2325,8 @@ vext_vx_rm_2(void *vd, void *v0, target_long s1, void *vs2, uint32_t vta = vext_vta(desc); uint32_t vma = vext_vma(desc); + VSTART_CHECK_EARLY_EXIT(env, vl); + switch (env->vxrm) { case 0: /* rnu */ vext_vx_rm_1(vd, v0, s1, vs2, @@ -4662,6 +4662,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, \ uint32_t i; \ TD s1 = *((TD *)vs1 + HD(0)); \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ TS2 s2 = *((TS2 *)vs2 + HS2(i)); \ if (!vm && !vext_elem_mask(v0, i)) { \ @@ -4750,6 +4752,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, \ uint32_t i; \ TD s1 = *((TD *)vs1 + HD(0)); \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ TS2 s2 = *((TS2 *)vs2 + HS2(i)); \ if (!vm && !vext_elem_mask(v0, i)) { \ @@ -4914,6 +4918,8 @@ static void vmsetm(void *vd, void *v0, void *vs2, CPURISCVState *env, int i; bool first_mask_bit = false; + VSTART_CHECK_EARLY_EXIT(env, vl); + for (i = env->vstart; i < vl; i++) { if (!vm && !vext_elem_mask(v0, i)) { /* set masked-off elements to 1s */ @@ -4986,6 +4992,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs2, CPURISCVState *env, \ uint32_t sum = 0; \ int i; \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ if (!vm && !vext_elem_mask(v0, i)) { \ /* set masked-off elements to 1s */ \ @@ -5344,6 +5352,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, void *vs2, \ uint32_t vta = vext_vta(desc); \ uint32_t num = 0, i; \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ if (!vext_elem_mask(vs1, i)) { \ continue; \ -- 2.48.1