[RV64_DYNAREC] Eliminate redundant vsetvli by tracking its usage (#1886)

6 files changed, 20 insertions, 5 deletions

diff --git a/src/dynarec/rv64/dynarec_rv64_helper.c b/src/dynarec/rv64/dynarec_rv64_helper.c
index bddb329c..975dff34 100644
--- a/src/dynarec/rv64/dynarec_rv64_helper.c
+++ b/src/dynarec/rv64/dynarec_rv64_helper.c
@@ -2614,11 +2614,16 @@ int vector_vsetvli(dynarec_rv64_t* dyn, int ninst, int s1, int sew, int vlmul, f
      *                    mu            tu          sew      lmul */
     uint32_t vtypei = (0b0 << 7) | (0b0 << 6) | (sew << 3) | vlmul;
     uint32_t vl = (int)((float)(16 >> sew) * multiple);
-    if (vl <= 31) {
-        VSETIVLI(xZR, vl, vtypei);
-    } else {
-        ADDI(s1, xZR, vl);
-        VSETVLI(xZR, s1, vtypei);
+
+    if (dyn->inst_sew == VECTOR_SEWNA || dyn->inst_vl == 0 || dyn->inst_sew != sew || dyn->inst_vl != vl) {
+        if (vl <= 31) {
+            VSETIVLI(xZR, vl, vtypei);
+        } else {
+            ADDI(s1, xZR, vl);
+            VSETVLI(xZR, s1, vtypei);
+        }
     }
+    dyn->inst_sew = sew;
+    dyn->inst_vl = vl;
     return sew;
 }
diff --git a/src/dynarec/rv64/dynarec_rv64_pass0.h b/src/dynarec/rv64/dynarec_rv64_pass0.h
index d0d81a6f..4a1603d0 100644
--- a/src/dynarec/rv64/dynarec_rv64_pass0.h
+++ b/src/dynarec/rv64/dynarec_rv64_pass0.h
@@ -30,6 +30,8 @@
         dyn->e.olds[i].v = 0;                                    \
     dyn->insts[ninst].f_entry = dyn->f;                          \
     dyn->insts[ninst].vector_sew_entry = dyn->vector_sew;        \
+    dyn->inst_sew = VECTOR_SEWNA;                                \
+    dyn->inst_vl = 0;                                            \
     if (ninst)                                                   \
         dyn->insts[ninst - 1].x64.size = dyn->insts[ninst].x64.addr - dyn->insts[ninst - 1].x64.addr;
 
diff --git a/src/dynarec/rv64/dynarec_rv64_pass1.h b/src/dynarec/rv64/dynarec_rv64_pass1.h
index 5360f767..0aa8e010 100644
--- a/src/dynarec/rv64/dynarec_rv64_pass1.h
+++ b/src/dynarec/rv64/dynarec_rv64_pass1.h
@@ -8,6 +8,8 @@
     for (int i = 0; i < 16; ++i)                          \
         dyn->e.olds[i].v = 0;                             \
     dyn->insts[ninst].vector_sew_entry = dyn->vector_sew; \
+    dyn->inst_sew = VECTOR_SEWNA;                         \
+    dyn->inst_vl = 0;                                     \
     dyn->e.swapped = 0;                                   \
     dyn->e.barrier = 0
 
diff --git a/src/dynarec/rv64/dynarec_rv64_pass2.h b/src/dynarec/rv64/dynarec_rv64_pass2.h
index 4f41f628..71b14b2e 100644
--- a/src/dynarec/rv64/dynarec_rv64_pass2.h
+++ b/src/dynarec/rv64/dynarec_rv64_pass2.h
@@ -9,6 +9,8 @@
 #define EMIT(A)     do {dyn->insts[ninst].size+=4; dyn->native_size+=4;}while(0)
 #define NEW_INST                                                                                                                                                               \
     dyn->vector_sew = dyn->insts[ninst].vector_sew_entry;                                                                                                                      \
+    dyn->inst_sew = VECTOR_SEWNA;                                                                                                                                              \
+    dyn->inst_vl = 0;                                                                                                                                                          \
     if (ninst) {                                                                                                                                                               \
         dyn->insts[ninst].address = (dyn->insts[ninst - 1].address + dyn->insts[ninst - 1].size);                                                                              \
         dyn->insts_size += 1 + ((dyn->insts[ninst - 1].x64.size > (dyn->insts[ninst - 1].size / 4)) ? dyn->insts[ninst - 1].x64.size : (dyn->insts[ninst - 1].size / 4)) / 15; \
diff --git a/src/dynarec/rv64/dynarec_rv64_pass3.h b/src/dynarec/rv64/dynarec_rv64_pass3.h
index 995b7f3a..85337a61 100644
--- a/src/dynarec/rv64/dynarec_rv64_pass3.h
+++ b/src/dynarec/rv64/dynarec_rv64_pass3.h
@@ -14,6 +14,8 @@
 #define MESSAGE(A, ...)  if(box64_dynarec_dump) dynarec_log(LOG_NONE, __VA_ARGS__)
 #define NEW_INST                                                                                                  \
     dyn->vector_sew = dyn->insts[ninst].vector_sew_entry;                                                         \
+    dyn->inst_sew = VECTOR_SEWNA;                                                                                 \
+    dyn->inst_vl = 0;                                                                                             \
     if (box64_dynarec_dump) print_newinst(dyn, ninst);                                                            \
     if (ninst) {                                                                                                  \
         addInst(dyn->instsize, &dyn->insts_size, dyn->insts[ninst - 1].x64.size, dyn->insts[ninst - 1].size / 4); \
diff --git a/src/dynarec/rv64/dynarec_rv64_private.h b/src/dynarec/rv64/dynarec_rv64_private.h
index f3fde565..ca1d5e96 100644
--- a/src/dynarec/rv64/dynarec_rv64_private.h
+++ b/src/dynarec/rv64/dynarec_rv64_private.h
@@ -156,6 +156,8 @@ typedef struct dynarec_rv64_s {
     uint8_t             abort;
     uint8_t             vector_sew; // current sew status
     uint8_t             vector_eew; // current effective sew status, should only be used after SET_ELEMENT_WIDTH
+    uint8_t             inst_sew;   // sew inside current instruction, for vsetvli elimination
+    uint8_t             inst_vl;    // vl inside current instruction, for vsetvli elimination
 } dynarec_rv64_t;
 
 // v0 is hardware wired to vector mask register, which should be always reserved