From a820983749a2d3eebcc36b5a3ae34436fd52db45 Mon Sep 17 00:00:00 2001
From: gubin <gubin_yewu@cmss.chinamobile.com>
Date: Sat, 11 Jan 2025 10:54:33 +0800
Subject: [PATCH] target/riscv/vector_helper.c: optimize loops in ldst helpers

cherry-pick from 0a11629c915f61df798919db51a18ffe4649cb65

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 <richard.henderson@linaro.org>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240314175704.478276-11-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: gubin <gubin_yewu@cmss.chinamobile.com>
---
 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 42ffd3a68a..b5acf81cc0 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -196,7 +196,7 @@ 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)) {
@@ -262,7 +262,7 @@ 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);
@@ -376,7 +376,7 @@ 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)) {
-- 
2.41.0.windows.1