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

[Daniel Henrique Barboza <dbarboza@ventanamicro.com>]

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>
---
 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