Why does the performance decrease as the optimize_level increases?

[qwe661234]

Hi,

I have integrated the C2MIR into our virtual machine rv32emu and observed that the performance of our virtual machine decreases when I increase the optimize_level using the MIR API MIR_gen_set_optimize_level. I would like to inquire about the reasons behind this phenomenon, thx.

The MIR of these two different optimize_level_1 and optimize_level_3 is the same, so I list the machine code of them.

Machine code generated by c2mir_compile from same MIR

Example

• optimize_level_1

0:  07                      pop    es
1:  f1                      icebp
2:  56                      push   esi
3:  e8 a7 00 0b b4          call   0xb40b00af
8:  90                      nop
9:  e3 ff                   jecxz  0xa
b:  41                      inc    ecx

• optimize_level_3

0:  07                      pop    es
1:  ff 94 e1 52 18 0b b4    call   DWORD PTR [ecx+eiz*8-0x4bf4e7ae]
8:  90                      nop
9:  e3 ff                   jecxz  0xa
b:  41                      inc    ecx
c:  00 00                   add    BYTE PTR [eax],al
e:  06                      push   es
f:  c8 d4 8f 82             enter  0x8fd4,0x82
13: 46                      inc    esi
14: c8 94 80 89             enter  0x8094,0x89
18: 48                      dec    eax
19: 58                      pop    eax
1a: ec                      in     al,dx
1b: 83 48 f8 24             or     DWORD PTR [eax-0x8],0x24
1f: 08 94 cb 86 58 94 cb    or     BYTE PTR [ebx+ecx*8-0x346ba77a],dl
26: 05 d0 89 4c c8          add    eax,0xc84c89d0
2b: 75 89                   jne    0xffffffb6
2d: 4c                      dec    esp
2e: c0 6d 08 38             shr    BYTE PTR [ebp+0x8],0x38
32: b4 8d                   mov    ah,0x8d
34: f8                      clc
35: b4 8d                   mov    ah,0x8d
37: 07                      pop    es
38: d0 c7                   rol    bh,1
3a: 00 8b 4c 00 00 00       add    BYTE PTR [ebx+0x4c],cl
40: e0 08                   loopne 0x4a
42: d4 80                   aam    0x80
44: 00 00                   add    BYTE PTR [eax],al
46: 00 05 84 30 28 b4       add    BYTE PTR ds:0xb4283084,al
4c: 80 00 00                add    BYTE PTR [eax],0x0
4f: 17                      pop    ss
50: 09 30                   or     DWORD PTR [eax],esi
52: 48                      dec    eax
53: 0a 89 48 01 48 8d       or     cl,BYTE PTR [ecx-0x72b7feb8]
59: 48                      dec    eax
5a: 04 84                   add    al,0x84
5c: c7                      (bad)
5d: 08 d4                   or     ah,dl
5f: 85 84 38 d0 ff ff ff    test   DWORD PTR [eax+edi*1-0x30],eax
66: ff                      (bad)
67: b9 48 06 63 08          mov    ecx,0x8630648
6c: 0c 8d                   or     al,0x8d
6e: 48                      dec    eax
6f: 00 00                   add    BYTE PTR [eax],al
71: 00 00                   add    BYTE PTR [eax],al
73: 0d 88 38 d4 80          or     eax,0x80d43888
78: e8 90 38 89 04          call   0x489390d
7d: 79 8d                   jns    0xc
7f: 08 8b 00 04 80 00       or     BYTE PTR [ebx+0x800400],cl
85: 00 00                   add    BYTE PTR [eax],al
87: 05 84 3c 70 89          add    eax,0x89703c84
8c: 48                      dec    eax
8d: 01 79 8d                add    DWORD PTR [ecx-0x73],edi
90: 48                      dec    eax
91: 0a 8b 0c e3 b5 87       or     cl,BYTE PTR [ebx-0x784a1cf4]
97: 38 b0 e8 b3 a0 88       cmp    BYTE PTR [eax-0x775f4c18],dh
9d: b0 00                   mov    al,0x0
9f: 00 00                   add    BYTE PTR [eax],al
a1: f8                      clc
a2: 40                      inc    eax
a3: f0 30 89 ff ff ff 40    lock xor BYTE PTR [ecx+0x40ffffff],cl
aa: b1 8d                   mov    cl,0x8d
ac: 08 30                   or     BYTE PTR [eax],dh
ae: 88 b0 00 00 00 ce       mov    BYTE PTR [eax-0x32000000],dh
b4: 90                      nop
b5: 7d 4e                   jge    0x105
b7: 90                      nop
b8: 88 90 4c 10 58 43       mov    BYTE PTR [eax+0x4358104c],dl
be: c7 00 04 80 17 18       mov    DWORD PTR [eax],0x18178004
c4: d4 80                   aam    0x80
c6: a8 b4                   test   al,0xb4
c8: 80 73 8b 58             xor    BYTE PTR [ebx-0x75],0x58
cc: 4b                      dec    ebx
cd: 8d 48 32                lea    ecx,[eax+0x32]
d0: 89 03                   mov    DWORD PTR [ebx],eax
d2: 84 98 d4 c4 1c 68       test   BYTE PTR [eax+0x681cc4d4],bl
d8: 35 80 47 18 d0          xor    eax,0xd0184780
dd: 88 b3 18 94 10 58       mov    BYTE PTR [ebx+0x58109418],dh
e3: 43                      inc    ebx
e4: c7                      (bad)
e5: 30 89 01 71 8d 48       xor    BYTE PTR [ecx+0x488d7101],cl
eb: 0a 8b 48 00 04 85       or     cl,BYTE PTR [ebx-0x7afbffb8]
f1: 84 b8 d4 83 28 94       test   BYTE PTR [eax-0x6bd77c2c],bh
f7: 80 3d be 48 0f 8b 0c    cmp    BYTE PTR ds:0x8b0f48be,0xc
fe: 79 8d                   jns    0x8d
100:    04 80                   add    al,0x80
102:    00 00                   add    BYTE PTR [eax],al
104:    00 0f                   add    BYTE PTR [edi],cl
106:    ff                      (bad)
107:    ff 80 48 30 8b 49       inc    DWORD PTR [eax+0x498b3048]
10d:    c9                      leave
10e:    8b ce                   mov    ecx,esi
110:    03 0b                   add    ecx,DWORD PTR [ebx]
112:    60                      pusha
113:    f4                      hlt
114:    80 98 b4 1f 10 30 71    sbb    BYTE PTR [eax+0x30101fb4],0x71
11b:    8d 08                   lea    ecx,[eax]
11d:    8b 0e                   mov    ecx,DWORD PTR [esi]
11f:    88 40 c9                mov    BYTE PTR [eax-0x37],al
122:    05 84 3c 73 08          add    eax,0x8733c84
127:    90                      nop
128:    40                      inc    eax
129:    71 8d                   jno    0xb8
12b:    48                      dec    eax
12c:    0a 8b 48 00 00 05       or     cl,BYTE PTR [ebx+0x5000048]
132:    84 b8 d4 83 28 94       test   BYTE PTR [eax-0x6bd77c2c],bh
138:    80 10 48                adc    BYTE PTR [eax],0x48
13b:    42                      inc    edx
13c:    66 8d 44 58 73          lea    ax,[eax+ebx*2+0x73]
141:    8b 08                   mov    ecx,DWORD PTR [eax]
143:    8b 26                   mov    esp,DWORD PTR [esi]
145:    89 44 3c 71             mov    DWORD PTR [esp+edi*1+0x71],eax
149:    8d 0c 72                lea    ecx,[edx+esi*2]
14c:    08 94 40 46 18 d4 40    or     BYTE PTR [eax+eax*2+0x40d41846],dl
153:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
156:    00 00                   add    BYTE PTR [eax],al
158:    00 58 43                add    BYTE PTR [eax+0x43],bl
15b:    02 28                   add    ch,BYTE PTR [eax]
15d:    94                      xchg   esp,eax
15e:    c0 16 18                rcl    BYTE PTR [esi],0x18
161:    d4 c0                   aam    0xc0
163:    a0 ff ff f8 3c          mov    al,ds:0x3cf8ffff
168:    bf 48 0f 8b 08          mov    edi,0x88b0f48
16d:    bc f0 34 80 00          mov    esp,0x8034f0
172:    00 00                   add    BYTE PTR [eax],al
174:    00 8b f9 03 48 38       add    BYTE PTR [ebx+0x384803f9],cl
17a:    8b 49 c9                mov    ecx,DWORD PTR [ecx-0x37]
17d:    0f 88 40 c9 b6 0f       js     0xfb6cac3
183:    48                      dec    eax
184:    0e                      push   cs
185:    0c 73                   or     al,0x73
187:    88 90 47 98 d0 88       mov    BYTE PTR [eax-0x772f67b9],dl
18d:    b0 8b                   mov    al,0x8b
18f:    48                      dec    eax
190:    00 00                   add    BYTE PTR [eax],al
192:    00 00                   add    BYTE PTR [eax],al
194:    58                      pop    eax
195:    43                      inc    ebx
196:    03 a8 94 80 17 98       add    ebp,DWORD PTR [eax-0x67e87f6c]
19c:    d4 80                   aam    0x80
19e:    a0 87 98 d4 85          mov    al,ds:0x85d49887
1a3:    84 b8 d4 80 21 8b       test   BYTE PTR [eax-0x74de7f2c],bh
1a9:    44                      inc    esp
1aa:    08 03                   or     BYTE PTR [ebx],al
1ac:    49                      dec    ecx
1ad:    0f 8b 06 18 d4 40       jnp    0x40d419b9
1b3:    88 b2 68 94 40 58       mov    BYTE PTR [edx+0x58409468],dh
1b9:    43                      inc    ebx
1ba:    c7                      (bad)
1bb:    20 89 44 04 08 d4       and    BYTE PTR [ecx-0x2bf7fbbc],cl
1c1:    c0 a8 b4 80 00 00 00    shr    BYTE PTR [eax+0x80b4],0x0
1c8:    83 0f 8b                or     DWORD PTR [edi],0xffffff8b
1cb:    22 89 4c 01 61 04       and    cl,BYTE PTR [ecx+0x461014c]
1d1:    40                      inc    eax
1d2:    80 34 9c 98             xor    BYTE PTR [esp+ebx*4],0x98
1d6:    b5 0c                   mov    ch,0xc
1d8:    10 89 44 00 00 00       adc    BYTE PTR [ecx+0x44],cl
1de:    c0 a3 8b 0c 98 b5 4c    shl    BYTE PTR [ebx-0x4a67f375],0x4c
1e5:    18 30                   sbb    BYTE PTR [eax],dh
1e7:    f8                      clc
1e8:    b2 10                   mov    dl,0x10
1ea:    bc a3 8b 44 08          mov    esp,0x8448ba3
1ef:    03 49 04                add    ecx,DWORD PTR [ecx+0x4]
1f2:    40                      inc    eax
1f3:    88 b2 18 94 40 00       mov    BYTE PTR [edx+0x409418],dh
1f9:    00 43 c7                add    BYTE PTR [ebx-0x39],al
1fc:    20 89 44 04 61 8d       and    BYTE PTR [ecx-0x729efbbc],cl
202:    0a 8b 48 00 00 00       or     cl,BYTE PTR [ebx+0x48]
208:    00 58 08                add    BYTE PTR [eax+0x8],bl
20b:    b2 28                   mov    dl,0x28
20d:    94                      xchg   esp,eax
20e:    c0 16 18                rcl    BYTE PTR [esi],0x18
211:    d4 c0                   aam    0xc0
213:    20 89 44 04 61 8d       and    BYTE PTR [ecx-0x729efbbc],cl
219:    44                      inc    esp
21a:    08 04 80                or     BYTE PTR [eax+eax*4],al
21d:    00 00                   add    BYTE PTR [eax],al
21f:    00 05 84 3c 70 89       add    BYTE PTR ds:0x89703c84,al
225:    4c                      dec    esp
226:    01 61 8d                add    DWORD PTR [ecx-0x73],esp
229:    4c                      dec    esp
22a:    0a 8b 0c 98 b6 8c       or     cl,BYTE PTR [ebx-0x734967f4]
230:    18 30                   sbb    BYTE PTR [eax],dh
232:    f8                      clc
233:    b2 20                   mov    dl,0x20
235:    e8 be 10 34 c2          call   0xc23412f8
23a:    08 b4 d0 8d 44 08 8b    or     BYTE PTR [eax+edx*8-0x74f7bb73],dh
241:    24 0c                   and    al,0xc
243:    89 41 05                mov    DWORD PTR [ecx+0x5],eax
246:    84 3c 72                test   BYTE PTR [edx+esi*2],bh
249:    08 94 40 46 10 4c 0a    or     BYTE PTR [eax+eax*2+0xa4c1046],dl
250:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
253:    00 00                   add    BYTE PTR [eax],al
255:    00 0f                   add    BYTE PTR [edi],cl
257:    8b 22                   mov    esp,DWORD PTR [edx]
259:    89 4c 01 61             mov    DWORD PTR [ecx+eax*1+0x61],ecx
25d:    8d 08                   lea    ecx,[eax]
25f:    03 49 c9                add    ecx,DWORD PTR [ecx-0x37]
262:    8b 04 c1                mov    eax,DWORD PTR [ecx+eax*8]
265:    83 08 8b                or     DWORD PTR [eax],0xffffff8b
268:    26 89 44 21 8b          mov    DWORD PTR es:[ecx+eiz*1-0x75],eax
26d:    44                      inc    esp
26e:    0c 72                   or     al,0x72
270:    08 94 40 46 18 d4 40    or     BYTE PTR [eax+eax*2+0x40d41846],dl
277:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
27a:    00 00                   add    BYTE PTR [eax],al
27c:    00 58 43                add    BYTE PTR [eax+0x43],bl
27f:    02 28                   add    ch,BYTE PTR [eax]
281:    94                      xchg   esp,eax
282:    c0 16 18                rcl    BYTE PTR [esi],0x18
285:    d4 c0                   aam    0xc0
287:    a0 49 c9 8b 58          mov    al,ds:0x588bc949
28c:    c1 83 0f 8b 0b 8a 38    rol    DWORD PTR [ebx-0x75f474f1],0x38
293:    b4 40                   mov    ah,0x40
295:    80 30 c1                xor    BYTE PTR [eax],0xc1
298:    83 0f 8b                or     DWORD PTR [edi],0xffffff8b
29b:    21 89 44 00 08 b4       and    DWORD PTR [ecx-0x4bf7ffbc],ecx
2a1:    40                      inc    eax
2a2:    80 34 9c 98             xor    BYTE PTR [esp+ebx*4],0x98
2a6:    b5 c0                   mov    ch,0xc0
2a8:    21 89 44 00 00 00       and    DWORD PTR [ecx+0x44],ecx
2ae:    b4 a3                   mov    ah,0xa3
2b0:    08 94 40 46 18 d4 40    or     BYTE PTR [eax+eax*2+0x40d41846],dl
2b7:    88 b0 58 43 c7 20       mov    BYTE PTR [eax+0x20c74358],dh
2bd:    04 c0                   add    al,0xc0
2bf:    16                      push   ss
2c0:    18 d4                   sbb    ah,dl
2c2:    c0 a8 b4 80 46 18 d4    shr    BYTE PTR [eax+0x184680b4],0xd4
2c9:    40                      inc    eax
2ca:    88 b2 28 90 58 43       mov    BYTE PTR [edx+0x43589028],dh
2d0:    c7                      (bad)
2d1:    20 89 44 06 18 d4       and    BYTE PTR [ecx-0x2be7f9bc],cl
2d7:    c0 a8 b4 80 00 00 c1    shr    BYTE PTR [eax+0x80b4],0xc1
2de:    83 0f 8b                or     DWORD PTR [edi],0xffffff8b
2e1:    22 89 4c 01 03 4c       and    cl,BYTE PTR [ecx+0x4c03014c]
2e7:    20 8b 4d c9 8b 6c       and    BYTE PTR [ebx+0x6c8bc94d],cl
2ed:    06                      push   es
2ee:    6c                      ins    BYTE PTR es:[edi],dx
2ef:    9b                      fwait
2f0:    70 f4                   jo     0x2e6
2f2:    80 e8 be                sub    al,0xbe
2f5:    10 8d 44 08 8b 24       adc    BYTE PTR [ebp+0x248b0844],cl
2fb:    0c 89                   or     al,0x89
2fd:    41                      inc    ecx
2fe:    05 84 3c 72 08          add    eax,0x8723c84
303:    94                      xchg   esp,eax
304:    40                      inc    eax
305:    46                      inc    esi
306:    10 4c 0a 8b             adc    BYTE PTR [edx+ecx*1-0x75],cl
30a:    48                      dec    eax
30b:    00 00                   add    BYTE PTR [eax],al
30d:    00 00                   add    BYTE PTR [eax],al
30f:    0f 8b 22 89 4c 01       jnp    0x14c8c37
315:    61                      popa
316:    8d 08                   lea    ecx,[eax]
318:    03 49 c9                add    ecx,DWORD PTR [ecx-0x37]
31b:    8b 08                   mov    ecx,DWORD PTR [eax]
31d:    c1 83 08 8b 26 89 44    rol    DWORD PTR [ebx-0x76d974f8],0x44
324:    21 8b 44 0c 72 08       and    DWORD PTR [ebx+0x8720c44],ecx
32a:    94                      xchg   esp,eax
32b:    40                      inc    eax
32c:    46                      inc    esi
32d:    18 d4                   sbb    ah,dl
32f:    40                      inc    eax
330:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
333:    00 00                   add    BYTE PTR [eax],al
335:    00 58 43                add    BYTE PTR [eax+0x43],bl
338:    02 28                   add    ch,BYTE PTR [eax]
33a:    94                      xchg   esp,eax
33b:    c0 16 18                rcl    BYTE PTR [esi],0x18
33e:    d4 c0                   aam    0xc0
340:    a0 49 c9 8b 60          mov    al,ds:0x608bc949
345:    c1 83 0f 8b 0b 0a 38    rol    DWORD PTR [ebx+0xa0b8b0f],0x38
34c:    b4 40                   mov    ah,0x40
34e:    80 30 c1                xor    BYTE PTR [eax],0xc1
351:    83 0f 8b                or     DWORD PTR [edi],0xffffff8b
354:    21 89 44 00 08 b4       and    DWORD PTR [ecx-0x4bf7ffbc],ecx
35a:    40                      inc    eax
35b:    80 34 9c 98             xor    BYTE PTR [esp+ebx*4],0x98
35f:    b6 40                   mov    dh,0x40
361:    21 89 44 00 00 00       and    DWORD PTR [ecx+0x44],ecx
367:    ac                      lods   al,BYTE PTR ds:[esi]
368:    a3 08 94 40 46          mov    ds:0x46409408,eax
36d:    18 d4                   sbb    ah,dl
36f:    40                      inc    eax
370:    88 b0 58 43 c7 20       mov    BYTE PTR [eax+0x20c74358],dh
376:    04 c0                   add    al,0xc0
378:    16                      push   ss
379:    18 d4                   sbb    ah,dl
37b:    c0 a8 b4 80 46 18 d4    shr    BYTE PTR [eax+0x184680b4],0xd4
382:    40                      inc    eax
383:    88 b2 28 90 58 43       mov    BYTE PTR [edx+0x43589028],dh
389:    c7                      (bad)
38a:    20 89 44 06 18 d4       and    BYTE PTR [ecx-0x2be7f9bc],cl
390:    c0 a8 b4 80 00 00 c1    shr    BYTE PTR [eax+0x80b4],0xc1
397:    83 0f 8b                or     DWORD PTR [edi],0xffffff8b
39a:    22 89 4c 01 03 4c       and    cl,BYTE PTR [ecx+0x4c03014c]
3a0:    20 8b 4d c9 8b 6e       and    BYTE PTR [ebx+0x6e8bc94d],cl
3a6:    04 1c                   add    al,0x1c
3a8:    9b                      fwait
3a9:    60                      pusha
3aa:    f4                      hlt
3ab:    80 e8 be                sub    al,0xbe
3ae:    10 61 8d                adc    BYTE PTR [ecx-0x73],ah
3b1:    44                      inc    esp
3b2:    08 8b 24 0c 88 05       or     BYTE PTR [ebx+0x5880c24],cl
3b8:    84 3c 72                test   BYTE PTR [edx+esi*2],bh
3bb:    08 94 40 40 8d 4c 0a    or     BYTE PTR [eax+eax*2+0xa4c8d40],dl
3c2:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
3c5:    00 00                   add    BYTE PTR [eax],al
3c7:    05 84 b8 b2 28          add    eax,0x28b2b884
3cc:    94                      xchg   esp,eax
3cd:    c0 16 10                rcl    BYTE PTR [esi],0x10
3d0:    8b 26                   mov    esp,DWORD PTR [esi]
3d2:    89 44 52 61             mov    DWORD PTR [edx+edx*2+0x61],eax
3d6:    8d 44 02 08             lea    eax,[edx+eax*1+0x8]
3da:    94                      xchg   esp,eax
3db:    40                      inc    eax
3dc:    46                      inc    esi
3dd:    18 d4                   sbb    ah,dl
3df:    40                      inc    eax
3e0:    80 48 00 00             or     BYTE PTR [eax+0x0],0x0
3e4:    00 00                   add    BYTE PTR [eax],al
3e6:    58                      pop    eax
3e7:    43                      inc    ebx
3e8:    c7                      (bad)
3e9:    08 94 c0 16 18 d4 c0    or     BYTE PTR [eax+eax*8-0x3f2be7ea],dl
3f0:    a8 b0                   test   al,0xb0
3f2:    c4 a3 8b 44 22 0f       les    esp,FWORD PTR [ebx+0xf22448b]
3f8:    85 0f                   test   DWORD PTR [edi],ecx
3fa:    e1 3b                   loope  0x437
3fc:    44                      inc    esp
3fd:    0e                      push   cs
3fe:    8b 04 cc                mov    eax,DWORD PTR [esp+ecx*8]
401:    18 10                   sbb    BYTE PTR [eax],dl
403:    88 b0 00 00 00 48       mov    BYTE PTR [eax+0x48000000],dh
409:    be 90 88 90 00          mov    esi,0x908890
40e:    00 10                   add    BYTE PTR [eax],dl
410:    46                      inc    esi
411:    18 d4                   sbb    ah,dl
413:    40                      inc    eax
414:    88 b0 00 00 58 43       mov    BYTE PTR [eax+0x43580000],dh
41a:    c7                      (bad)
41b:    20 89 44 06 18 d4       and    BYTE PTR [ecx-0x2be7f9bc],cl
421:    c0 a8 b4 80 00 00 58    shr    BYTE PTR [eax+0x80b4],0x58
428:    63 8d 4c 22 89 4c       arpl   WORD PTR [ebp+0x4c89224c],cx
42e:    01 08                   add    DWORD PTR [eax],ecx
430:    34 95                   xor    al,0x95
432:    06                      push   es
433:    98                      cwde
434:    d4 40                   aam    0x40
436:    f8                      clc
437:    b0 88                   mov    al,0x88
439:    b2 42                   mov    dl,0x42
43b:    c8 94 52 cc             enter  0x5294,0xcc
43f:    40                      inc    eax
440:    c7                      (bad)
441:    28 89 44 04 69 8d       sub    BYTE PTR [ecx-0x7296fbbc],cl
447:    44                      inc    esp
448:    08 b4 80 00 00 00 05    or     BYTE PTR [eax+eax*4+0x5000000],dh
44f:    84 30                   test   BYTE PTR [eax],dh
451:    2a 89 4c 01 69 8d       sub    cl,BYTE PTR [ecx-0x7296feb4]
457:    4c                      dec    esp
458:    0a 08                   or     cl,BYTE PTR [eax]
45a:    d4 40                   aam    0x40
45c:    f8                      clc
45d:    b5 86                   mov    ch,0x86
45f:    b8 d4 c0 89 44          mov    eax,0x4489c0d4
464:    28 7d 8d                sub    BYTE PTR [ebp-0x73],bh
467:    49                      dec    ecx
468:    30 71 04                xor    BYTE PTR [ecx+0x4],dh
46b:    40                      inc    eax
46c:    46                      inc    esi
46d:    98                      cwde
46e:    d4 40                   aam    0x40
470:    88 b3 70 58 43 c7       mov    BYTE PTR [ebx-0x38bca790],dh
476:    28 89 01 69 8d 4c       sub    BYTE PTR [ecx+0x4c8d6901],cl
47c:    0a 8b 48 00 08 8b       or     cl,BYTE PTR [ebx-0x74f7ffb8]
482:    30 8b 44 2a 89 4c       xor    BYTE PTR [ebx+0x4c892a44],cl
488:    04 40                   add    al,0x40
48a:    00 00                   add    BYTE PTR [eax],al
48c:    dc 0a                   fmul   QWORD PTR [edx]
48e:    98                      cwde
48f:    d4 40                   aam    0x40
491:    8d 45 58                lea    eax,[ebp+0x58]
494:    4b                      dec    ebx
495:    8d 48 28                lea    ecx,[eax+0x28]
498:    89 08                   mov    DWORD PTR [eax],ecx
49a:    94                      xchg   esp,eax
49b:    c0 45 18 d4             rol    BYTE PTR [ebp+0x18],0xd4
49f:    c0 46 e0 89             rol    BYTE PTR [esi-0x20],0x89
4a3:    45                      inc    ebp
4a4:    f0 5d                   lock pop ebp
4a6:    8b 4c f0 55             mov    ecx,DWORD PTR [eax+esi*8+0x55]
4aa:    05 84 3c 72 b0          add    eax,0xb0723c84
4af:    4c                      dec    esp
4b0:    01 69 8d                add    DWORD PTR [ecx-0x73],ebp
4b3:    4c                      dec    esp
4b4:    0a 8b 48 02 40 c0       or     cl,BYTE PTR [ebx-0x3fbffdb8]
4ba:    b4 10                   mov    ah,0x10
4bc:    f8                      clc
4bd:    b2 a8                   mov    dl,0xa8
4bf:    90                      nop
4c0:    69 8d 44 08 8b 09 89    imul   ecx,DWORD PTR [ebp+0x98b0844],0x84054189
4c7:    41 05 84
4ca:    3c 72                   cmp    al,0x72
4cc:    88 94 40 40 8d 4c 0a    mov    BYTE PTR [eax+eax*2+0xa4c8d40],dl
4d3:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
4d6:    00 00                   add    BYTE PTR [eax],al
4d8:    04 b8                   add    al,0xb8
4da:    d4 82                   aam    0x82
4dc:    a8 94                   test   al,0x94
4de:    c0 16 90                rcl    BYTE PTR [esi],0x90
4e1:    ff                      (bad)
4e2:    be 49 58 6b 63          mov    esi,0x636b5849
4e7:    4c                      dec    esp
4e8:    58                      pop    eax
4e9:    04 d0                   add    al,0xd0
4eb:    00 00                   add    BYTE PTR [eax],al
4ed:    00 0f                   add    BYTE PTR [edi],cl
4ef:    ff                      (bad)
4f0:    ff f0                   push   eax
4f2:    89 4c 1c 51             mov    DWORD PTR [esp+ebx*1+0x51],ecx
4f6:    8d 4c ee 03             lea    ecx,[esi+ebp*8+0x3]
4fa:    08 94 5f 85 d8 b4 cf    or     BYTE PTR [edi+ebx*2-0x304b277b],dl
501:    85 50 44                test   DWORD PTR [eax+0x44],edx
504:    04 69                   add    al,0x69
506:    8d 44 08 8b             lea    eax,[eax+ecx*1-0x75]
50a:    2b 05 84 3c 72 88       sub    eax,DWORD PTR ds:0x88723c84
510:    90                      nop
511:    16                      push   ss
512:    98                      cwde
513:    d4 c0                   aam    0xc0
515:    a8 b4                   test   al,0xb4
517:    80 00 e1                add    BYTE PTR [eax],0xe1
51a:    83 09 8b                or     DWORD PTR [ecx],0xffffff8b
51d:    41                      inc    ecx
51e:    2a 89 4c 08 d4 40       sub    cl,BYTE PTR [ecx+0x40d4084c]
524:    88 b0 98 94 10 30       mov    BYTE PTR [eax+0x30109498],dh
52a:    58                      pop    eax
52b:    43                      inc    ebx
52c:    c7                      (bad)
52d:    28 89 44 04 69 04       sub    BYTE PTR [ecx+0x4690444],cl
533:    c0 a8 b4 80 00 00 00    shr    BYTE PTR [eax+0x80b4],0x0
53a:    00 8b 41 2a 89 4c       add    BYTE PTR [ebx+0x4c892a41],cl
540:    01 69 8d                add    DWORD PTR [ecx-0x73],ebp
543:    0c 93                   or     al,0x93
545:    b4 15                   mov    ah,0x15
547:    84 b8 b4 40 90 88       test   BYTE PTR [eax-0x776fbf4c],bh
54d:    b0 00                   mov    al,0x0
54f:    00 00                   add    BYTE PTR [eax],al
551:    f8                      clc
552:    40                      inc    eax
553:    f0 88 90 00 00 10 0c    lock mov BYTE PTR [eax+0xc100000],dl
55a:    18 10                   sbb    BYTE PTR [eax],dl
55c:    44                      inc    esp
55d:    08 8b 00 00 03 40       or     BYTE PTR [ebx+0x40030000],cl
563:    e9 04 3c 70 88          jmp    0x8870416c
568:    94                      xchg   esp,eax
569:    40                      inc    eax
56a:    44                      inc    esp
56b:    98                      cwde
56c:    d0 a8 b4 80 00 00       shr    BYTE PTR [eax+0x80b4],1
572:    00 05 80 c7 0a 89       add    BYTE PTR ds:0x890ac780,al
578:    4c                      dec    esp
579:    01 49 8d                add    DWORD PTR [ecx-0x73],ecx
57c:    4c                      dec    esp
57d:    04 40                   add    al,0x40
57f:    88 b7 f7 f8 00 00       mov    BYTE PTR [edi+0xf8f7],dh
585:    60                      pusha
586:    43                      inc    ebx
587:    c7                      (bad)
588:    08 89 44 04 49 8d       or     BYTE PTR [ecx-0x72b6fbbc],cl
58e:    0a 8b 48 00 00 00       or     cl,BYTE PTR [ebx+0x48]
594:    00 58 04                add    BYTE PTR [eax+0x4],bl
597:    80 a8 94 c0 14 98 d4    sub    BYTE PTR [eax-0x67eb3f6c],0xd4
59e:    c0 ff ff                sar    bh,0xff
5a1:    ff                      (bad)
5a2:    7f b9                   jg     0x55d
5a4:    49                      dec    ecx
5a5:    0e                      push   cs
5a6:    63 09                   arpl   WORD PTR [ecx],cx
5a8:    0c 8d                   or     al,0x8d
5aa:    4e                      dec    esi
5ab:    00 00                   add    BYTE PTR [eax],al
5ad:    00 00                   add    BYTE PTR [eax],al
5af:    04 98                   add    al,0x98
5b1:    d4 40                   aam    0x40
5b3:    88 b0 e8 94 40 58       mov    BYTE PTR [eax+0x584094e8],dh
5b9:    43                      inc    ebx
5ba:    c7                      (bad)
5bb:    08 89 44 04 08 d4       or     BYTE PTR [ecx-0x2bf7fbbc],cl
5c1:    c0 a8 b4 80 00 00 00    shr    BYTE PTR [eax+0x80b4],0x0
5c8:    4b                      dec    ebx
5c9:    8d 4c 0a 89             lea    ecx,[edx+ecx*1-0x77]
5cd:    4c                      dec    esp
5ce:    01 49 08                add    DWORD PTR [ecx+0x8],ecx
5d1:    b4 40                   mov    ah,0x40
5d3:    80 34 90 f8             xor    BYTE PTR [eax+edx*4],0xf8
5d7:    b5 80                   mov    ch,0x80
5d9:    29 89 45 30 c1 83       sub    DWORD PTR [ecx-0x7c3ecfbb],ecx
5df:    49                      dec    ecx
5e0:    29 08                   sub    DWORD PTR [eax],ecx
5e2:    94                      xchg   esp,eax
5e3:    40                      inc    eax
5e4:    46                      inc    esi
5e5:    98                      cwde
5e6:    d4 40                   aam    0x40
5e8:    88 b0 58 43 c7 28       mov    BYTE PTR [eax+0x28c74358],dh
5ee:    04 c0                   add    al,0xc0
5f0:    16                      push   ss
5f1:    98                      cwde
5f2:    d4 c0                   aam    0xc0
5f4:    a8 b4                   test   al,0xb4
5f6:    80 8b 41 58 6b 8d 4c    or     BYTE PTR [ebx-0x7294a7bf],0x4c
5fd:    2a 89 03 98 b4 40       sub    cl,BYTE PTR [ecx+0x40b49803]
603:    80 34 92 40             xor    BYTE PTR [edx+edx*4],0x40
607:    c0 8b 3e 89 45 34 75    ror    BYTE PTR [ebx+0x3445893e],0x75
60e:    8d 4d 02                lea    ecx,[ebp+0x2]
611:    88 94 40 46 98 d4 40    mov    BYTE PTR [eax+eax*2+0x40d49846],dl
618:    80 48 00 00             or     BYTE PTR [eax+0x0],0x0
61c:    00 00                   add    BYTE PTR [eax],al
61e:    58                      pop    eax
61f:    43                      inc    ebx
620:    c7                      (bad)
621:    08 94 c0 16 98 d4 c0    or     BYTE PTR [eax+eax*8-0x3f2b67ea],dl
628:    a8 b0                   test   al,0xb0
62a:    55                      push   ebp
62b:    89 4c 58 53             mov    DWORD PTR [eax+ebx*2+0x53],ecx
62f:    8d 4c 2a 08             lea    ecx,[edx+ebp*1+0x8]
633:    b4 c0                   mov    ah,0xc0
635:    e2 30                   loop   0x667
637:    98                      cwde
638:    b4 1e                   mov    ah,0x1e
63a:    80 89 41 14 6a 8d 4d    or     BYTE PTR [ecx-0x7295ebbf],0x4d
641:    e8 55 04 79 8d          call   0x8d790a9b
646:    44                      inc    esp
647:    08 8b 00 4d 05 84       or     BYTE PTR [ebx-0x7bfab300],cl
64d:    3c 73                   cmp    al,0x73
64f:    88 94 40 79 8d 4c 0a    mov    BYTE PTR [eax+eax*2+0xa4c8d79],dl
656:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
659:    00 05 85 38 d4 c3       add    BYTE PTR ds:0xc3d43885,al
65f:    a8 94                   test   al,0x94
661:    c0 10 44                rcl    BYTE PTR [eax],0x44
664:    39 8b 45 e8 55 89       cmp    DWORD PTR [ebx-0x76aa17bb],ecx
66a:    4c                      dec    esp
66b:    08 b4 9e 05 58 94 c1    or     BYTE PTR [esi+ebx*4-0x3e6ba7fb],dh
672:    68 b0 cb 0b 41          push   0x410bcbb0
677:    e0 5d                   loopne 0x6d6
679:    8b 4c cf 01             mov    ecx,DWORD PTR [edi+ecx*8+0x1]
67d:    87 a8 d4 de 85 58       xchg   DWORD PTR [eax+0x5885ded4],ebp
683:    b4 c0                   mov    ah,0xc0
685:    45                      inc    ebp
686:    c7                      (bad)
687:    48                      dec    eax
688:    08 8b 0f 89 41 05       or     BYTE PTR [ebx+0x541890f],cl
68e:    d8 b4 c0 00 00 00 4e    fdiv   DWORD PTR [eax+eax*8+0x4e000000]
695:    80 55 89 4c             adc    BYTE PTR [ebp-0x77],0x4c
699:    19 14 8d 46 e8 01 08    sbb    DWORD PTR [ecx*4+0x801e846],edx
6a0:    94                      xchg   esp,eax
6a1:    4e                      dec    esi
6a2:    85 58 b4                test   DWORD PTR [eax-0x4c],ebx
6a5:    ce                      into
6a6:    80 e8 45                sub    al,0x45
6a9:    c7                      (bad)
6aa:    48                      dec    eax
6ab:    58                      pop    eax
6ac:    4b                      dec    ebx
6ad:    8d 48 0e                lea    ecx,[eax+0xe]
6b0:    84 d0                   test   al,dl
6b2:    34 80                   xor    al,0x80
6b4:    00 00                   add    BYTE PTR [eax],al
6b6:    00 00                   add    BYTE PTR [eax],al
6b8:    e8 45 c7 48 04          call   0x448ce02
6bd:    81 18 94 4e 85 58       sbb    DWORD PTR [eax],0x58854e94
6c3:    b4 c0                   mov    ah,0xc0
6c5:    1e                      push   ds
6c6:    84 5c 74 80             test   BYTE PTR [esp+esi*2-0x80],bl
6ca:    a8 b0                   test   al,0xb0
6cc:    8d 4e e8                lea    ecx,[esi-0x18]
6cf:    5d                      pop    ebp
6d0:    8b 4c 00 00             mov    ecx,DWORD PTR [eax+eax*1+0x0]
6d4:    08 b4 ce 85 58 94 c1    or     BYTE PTR [esi+ecx*8-0x3e6ba77b],dh
6db:    91                      xchg   ecx,eax
6dc:    40                      inc    eax
6dd:    55                      push   ebp
6de:    8b 45 12                mov    eax,DWORD PTR [ebp+0x12]
6e1:    89 4c e8 55             mov    DWORD PTR [eax+ebp*8+0x55],ecx
6e5:    04 c0                   add    al,0xc0
6e7:    e8 be 85 58 94          call   0x94588caa
6ec:    c0 00 41                rol    BYTE PTR [eax],0x41
6ef:    0a 34 8d 41 e8 55 8b    or     dh,BYTE PTR [ecx*4-0x74aa17bf]
6f6:    04 71                   add    al,0x71
6f8:    8d 08                   lea    ecx,[eax]
6fa:    8b 00                   mov    eax,DWORD PTR [eax]
6fc:    75 89                   jne    0x687
6fe:    05 84 3c 73 08          add    eax,0x8733c84
703:    90                      nop
704:    17                      pop    ss
705:    18 d4                   sbb    ah,dl
707:    80 a8 b4 80 00 41 00    sub    BYTE PTR [eax+0x410080b4],0x0
70e:    4d                      dec    ebp
70f:    8b 41 32                mov    eax,DWORD PTR [ecx+0x32]
712:    89 48 08                mov    DWORD PTR [eax+0x8],ecx
715:    8b 00                   mov    eax,DWORD PTR [eax]
717:    4d                      dec    ebp
718:    89 41 0f                mov    DWORD PTR [ecx+0xf],eax
71b:    0b 05 84 3c 73 08       or     eax,DWORD PTR ds:0x8733c84
721:    90                      nop
722:    47                      inc    edi
723:    18 d0                   sbb    al,dl
725:    48                      dec    eax
726:    0a 8b 48 00 00 00       or     cl,BYTE PTR [ebx+0x48]
72c:    00 08                   add    BYTE PTR [eax],cl
72e:    b4 13                   mov    ah,0x13
730:    28 94 80 17 18 d0 98    sub    BYTE PTR [eax+eax*4-0x672fe7e9],dl
737:    bf 84 d8 b4 80          mov    edi,0x80b4d884
73c:    07                      pop    es
73d:    50                      push   eax
73e:    f8                      clc
73f:    40                      inc    eax
740:    ff 13                   call   DWORD PTR [ebx]
742:    b0 10                   mov    al,0x10
744:    4b                      dec    ebx
745:    18 d0                   sbb    al,dl
747:    88 b0 8b 00 00 00       mov    BYTE PTR [eax+0x8b],dh
74d:    0c e9                   or     al,0xe9
74f:    30 89 04 ae 90 88       xor    BYTE PTR [ecx-0x776f51fc],cl
755:    90                      nop
756:    4c                      dec    esp
757:    18 30                   sbb    BYTE PTR [eax],dh
759:    80 58 43 c7             sbb    BYTE PTR [eax+0x43],0xc7
75d:    00 00                   add    BYTE PTR [eax],al
75f:    01 07                   add    DWORD PTR [edi],eax
761:    18 d4                   sbb    ah,dl
763:    80 a8 b4 80 00 00 41    sub    BYTE PTR [eax+0x80b4],0x41
76a:    31 8b 41 32 89 48       xor    DWORD PTR [ebx+0x48893241],ecx
770:    01 0c 84                add    DWORD PTR [esp+eax*4],ecx
773:    0f f1 3b                psllw  mm7,QWORD PTR [ebx]
776:    0e                      push   cs
777:    8b 08                   mov    ecx,DWORD PTR [eax]
779:    9d                      popf
77a:    87 18                   xchg   DWORD PTR [eax],ebx
77c:    d0 88 b0 00 00 88       ror    BYTE PTR [eax-0x77ffff50],1
782:    b0 00                   mov    al,0x0
784:    00 00                   add    BYTE PTR [eax],al
786:    ce                      into
787:    93                      xchg   ebx,eax
788:    00 11                   add    BYTE PTR [ecx],dl
78a:    3e 90                   ds nop
78c:    88 90 4c 18 30 58       mov    BYTE PTR [eax+0x5830184c],dl
792:    43                      inc    ebx
793:    c7 00 00 01 71 8d       mov    DWORD PTR [eax],0x8d710100
799:    48                      dec    eax
79a:    0a 8b 48 00 08 03       or     cl,BYTE PTR [ebx+0x3080048]
7a0:    49                      dec    ecx
7a1:    0f 8b 32 89 48 08       jnp    0x84890d9
7a7:    b3 18                   mov    bl,0x18
7a9:    94                      xchg   esp,eax
7aa:    13 1b                   adc    ebx,DWORD PTR [ebx]
7ac:    60                      pusha
7ad:    f4                      hlt
7ae:    80 43 c7 30             add    BYTE PTR [ebx-0x39],0x30
7b2:    89 04 71                mov    DWORD PTR [ecx+esi*2],eax
7b5:    8d 08                   lea    ecx,[eax]
7b7:    0a 8b 48 00 00 00       or     cl,BYTE PTR [ebx+0x48]
7bd:    00 58 04                add    BYTE PTR [eax+0x4],bl
7c0:    13 28                   adc    ebp,DWORD PTR [eax]
7c2:    94                      xchg   esp,eax
7c3:    80 17 18                adc    BYTE PTR [edi],0x18
7c6:    d4 80                   aam    0x80
7c8:    f4                      hlt
7c9:    80 80 34 92 40 c8 b0    add    BYTE PTR [eax-0x37bf6dcc],0xb0
7d0:    8d 08                   lea    ecx,[eax]
7d2:    8b 36                   mov    esi,DWORD PTR [esi]
7d4:    89 41 31                mov    DWORD PTR [ecx+0x31],eax
7d7:    b6 05                   mov    dh,0x5
7d9:    84 3c 73                test   BYTE PTR [ebx+esi*2],bh
7dc:    08 90 47 10 8d 48       or     BYTE PTR [eax+0x488d1047],dl
7e2:    0a 8b 48 00 00 00       or     cl,BYTE PTR [ebx+0x48]
7e8:    08 d0                   or     al,dl
7ea:    f8                      clc
7eb:    b3 28                   mov    bl,0x28
7ed:    94                      xchg   esp,eax
7ee:    80 17 10                adc    BYTE PTR [edi],0x10
7f1:    71 8d                   jno    0x780
7f3:    08 8b 37 89 01 71       or     BYTE PTR [ebx+0x71018937],cl
7f9:    05 84 3c 73 08          add    eax,0x8733c84
7fe:    90                      nop
7ff:    40                      inc    eax
800:    71 8d                   jno    0x78f
802:    48                      dec    eax
803:    0a 8b 48 00 00 02       or     cl,BYTE PTR [ebx+0x2000048]
809:    40                      inc    eax
80a:    c8 b4 13 28             enter  0x13b4,0x28
80e:    94                      xchg   esp,eax
80f:    80 10 8b                adc    BYTE PTR [eax],0x8b
812:    24 34                   and    al,0x34
814:    89 41 01                mov    DWORD PTR [ecx+0x1],eax
817:    71 8d                   jno    0x7a6
819:    04 3c                   add    al,0x3c
81b:    73 08                   jae    0x825
81d:    90                      nop
81e:    47                      inc    edi
81f:    18 d0                   sbb    al,dl
821:    80 a8 b4 80 00 00 00    sub    BYTE PTR [eax+0x80b4],0x0
828:    05 80 41 32 89          add    eax,0x89324180
82d:    48                      dec    eax
82e:    01 71 8d                add    DWORD PTR [ecx-0x73],esi
831:    48                      dec    eax
832:    0f f1 3b                psllw  mm7,QWORD PTR [ebx]
835:    0e                      push   cs
836:    8b 41 31                mov    eax,DWORD PTR [ecx+0x31]
839:    8b 08                   mov    ecx,DWORD PTR [eax]
83b:    d0 88 b0 00 00 00       ror    BYTE PTR [eax+0xb0],1
841:    c8 40 ce 93             enter  0xce40,0x93
845:    08 90 87 10 88 90       or     BYTE PTR [eax-0x6f77ef79],dl
84b:    4c                      dec    esp
84c:    18 30                   sbb    BYTE PTR [eax],dh
84e:    88 b0 00 58 43 c7       mov    BYTE PTR [eax-0x38bca800],dh
854:    00 00                   add    BYTE PTR [eax],al
856:    00 50 e9                add    BYTE PTR [eax-0x17],dl
859:    04 80                   add    al,0x80
85b:    a8 b4                   test   al,0xb4
85d:    80 00 00                add    BYTE PTR [eax],0x0
860:    00 00                   add    BYTE PTR [eax],al
862:    8b 41 32                mov    eax,DWORD PTR [ecx+0x32]
865:    89 48 01                mov    DWORD PTR [eax+0x1],ecx
868:    71 8d                   jno    0x7f7
86a:    08 8b 0f 89 0e 2b       or     BYTE PTR [ebx+0x2b0e890f],cl
870:    41                      inc    ecx
871:    09 05 84 3c 73 08       or     DWORD PTR ds:0x8733c84,eax
877:    90                      nop
878:    47                      inc    edi
879:    18 d0                   sbb    al,dl
87b:    48                      dec    eax
87c:    0a 8b 48 00 00 00       or     cl,BYTE PTR [ebx+0x48]
882:    00 08                   add    BYTE PTR [eax],cl
884:    b4 81                   mov    ah,0x81
886:    a8 94                   test   al,0x94
888:    80 15 98 d0 ff fe ba    adc    BYTE PTR ds:0xfeffd098,0xba
88f:    48                      dec    eax
890:    09 8b f0 4d 0c a2       or     DWORD PTR [ebx-0x5df3b210],ecx
896:    30 00                   xor    BYTE PTR [eax],al
898:    00 00                   add    BYTE PTR [eax],al
89a:    0f ff f0                ud0    esi,eax
89d:    8d 00                   lea    eax,[eax]
89f:    00 00                   add    BYTE PTR [eax],al
8a1:    06                      push   es
8a2:    e9 08 89 0c 0c          jmp    0xc0c91af
8a7:    74 85                   je     0x82e
8a9:    84 b8 90 44 a0 b0       test   BYTE PTR [eax-0x4f5fbb70],bh
8af:    5d                      pop    ebp
8b0:    8b 48 00                mov    ecx,DWORD PTR [eax+0x0]
8b3:    00 00                   add    BYTE PTR [eax],al
8b5:    01 0c 06                add    DWORD PTR [esi+eax*1],ecx
8b8:    d8 b4 cb 86 58 b4 c0    fdiv   DWORD PTR [ebx+ecx*8-0x3f4ba77a]
8bf:    d0 7d 8b                sar    BYTE PTR [ebp-0x75],1
8c2:    4c                      dec    esp
8c3:    c8 75 8b 4c             enter  0x8b75,0x4c
8c7:    02 46 c8                add    al,BYTE PTR [esi-0x38]
8ca:    b4 80                   mov    ah,0x80
8cc:    86 58 d4                xchg   BYTE PTR [eax-0x2c],bl
8cf:    80 c3 f8                add    bl,0xf8

Dhrystone Benchmark Result

optimize_level	Dhrystone (DMIPS)
1	2497
2	1793
3	1631

[snej]

I’m a noob (and know nothing about RISC-V), but I suspect you’ll be more likely to get an answer if you post the code as assembly rather than a bunch of hex, so someone trying to answer your question doesn’t have to go hunting for a disassembler first. It’s always best to give people the information they need, when asking for help.

[qwe661234]

Thanks for your recommendation, I'll try to disassemble the above x86 binary.