Re: [PATCH v6 9/9] target/riscv/vector_helper.c: optimize loops in ldst helpers

[Alistair Francis]

On Thu, Feb 22, 2024 at 7:33 AM Daniel Henrique Barboza
 wrote:
>
> Change the for loops in ldst helpers to do a single increment in the
> counter, and assign it env->vstart, to avoid re-reading from vstart
> every time.
>
> Suggested-by: Richard Henderson 
> Signed-off-by: Daniel Henrique Barboza 

Reviewed-by: Alistair Francis 

Alistair

> ---
>  target/riscv/vector_helper.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> index cc7290a1bb..1ab386830a 100644
> --- a/target/riscv/vector_helper.c
> +++ b/target/riscv/vector_helper.c
> @@ -208,7 +208,7 @@ vext_ldst_stride(void *vd, void *v0, target_ulong base,
>  uint32_t esz = 1 << log2_esz;
>  uint32_t vma = vext_vma(desc);
>
> -for (i = env->vstart; i < env->vl; i++, env->vstart++) {
> +for (i = env->vstart; i < env->vl; env->vstart = ++i) {
>  k = 0;
>  while (k < nf) {
>  if (!vm && !vext_elem_mask(v0, i)) {
> @@ -274,7 +274,7 @@ vext_ldst_us(void *vd, target_ulong base, CPURISCVState 
> *env, uint32_t desc,
>  uint32_t esz = 1 << log2_esz;
>
>  /* load bytes from guest memory */
> -for (i = env->vstart; i < evl; i++, env->vstart++) {
> +for (i = env->vstart; i < evl; env->vstart = ++i) {
>  k = 0;
>  while (k < nf) {
>  target_ulong addr = base + ((i * nf + k) << log2_esz);
> @@ -388,7 +388,7 @@ vext_ldst_index(void *vd, void *v0, target_ulong base,
>  uint32_t vma = vext_vma(desc);
>
>  /* load bytes from guest memory */
> -for (i = env->vstart; i < env->vl; i++, env->vstart++) {
> +for (i = env->vstart; i < env->vl; env->vstart = ++i) {
>  k = 0;
>  while (k < nf) {
>  if (!vm && !vext_elem_mask(v0, i)) {
> --
> 2.43.2
>
>

Re: [PATCH v6 9/9] target/riscv/vector_helper.c: optimize loops in ldst helpers

[Richard Henderson]

On 2/21/24 11:31, Daniel Henrique Barboza wrote:

Change the for loops in ldst helpers to do a single increment in the
counter, and assign it env->vstart, to avoid re-reading from vstart
every time.

Suggested-by: Richard Henderson
Signed-off-by: Daniel Henrique Barboza
---
  target/riscv/vector_helper.c | 6 +++---
  1 file changed, 3 insertions(+), 3 deletions(-)


Reviewed-by: Richard Henderson 

r~

[PATCH v6 9/9] target/riscv/vector_helper.c: optimize loops in ldst helpers

[Daniel Henrique Barboza]

Change the for loops in ldst helpers to do a single increment in the
counter, and assign it env->vstart, to avoid re-reading from vstart
every time.

Suggested-by: Richard Henderson 
Signed-off-by: Daniel Henrique Barboza 
---
 target/riscv/vector_helper.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index cc7290a1bb..1ab386830a 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -208,7 +208,7 @@ vext_ldst_stride(void *vd, void *v0, target_ulong base,
 uint32_t esz = 1 << log2_esz;
 uint32_t vma = vext_vma(desc);
 
-for (i = env->vstart; i < env->vl; i++, env->vstart++) {
+for (i = env->vstart; i < env->vl; env->vstart = ++i) {
 k = 0;
 while (k < nf) {
 if (!vm && !vext_elem_mask(v0, i)) {
@@ -274,7 +274,7 @@ vext_ldst_us(void *vd, target_ulong base, CPURISCVState 
*env, uint32_t desc,
 uint32_t esz = 1 << log2_esz;
 
 /* load bytes from guest memory */
-for (i = env->vstart; i < evl; i++, env->vstart++) {
+for (i = env->vstart; i < evl; env->vstart = ++i) {
 k = 0;
 while (k < nf) {
 target_ulong addr = base + ((i * nf + k) << log2_esz);
@@ -388,7 +388,7 @@ vext_ldst_index(void *vd, void *v0, target_ulong base,
 uint32_t vma = vext_vma(desc);
 
 /* load bytes from guest memory */
-for (i = env->vstart; i < env->vl; i++, env->vstart++) {
+for (i = env->vstart; i < env->vl; env->vstart = ++i) {
 k = 0;
 while (k < nf) {
 if (!vm && !vext_elem_mask(v0, i)) {
-- 
2.43.2