Open
Description
A small change in #110955 caused terrible regressions (>150 benchmarks) on Mono. I am going to workaround it in the codebase, but I guess it'd be nice to also optimize it in the mono runtime
static ReadOnlySpan<byte> TwoDigitsCharsAsBytes => MemoryMarshal.AsBytes<char>(
"00010203040506070809" +
"10111213141516171819" +
"20212223242526272829" +
"30313233343536373839" +
"40414243444546474849" +
"50515253545556575859" +
"60616263646566676869" +
"70717273747576777879" +
"80818283848586878889" +
"90919293949596979899");
static byte TestMethod(int i)
{
return TwoDigitsCharsAsBytes[i];
}Codegen on CoreCLR:
; Method Benchmarks:TestMethod(int):ubyte (FullOpts)
sub rsp, 40
mov rax, 0x2C88020576C
cmp ecx, 400
jae SHORT G_M2810_IG04
mov ecx, ecx
movzx rax, byte ptr [rax+rcx]
add rsp, 40
ret
G_M2810_IG04:
call CORINFO_HELP_RNGCHKFAIL
int3
; Total bytes of code: 39Codegen on Mono (JIT, x64):
*** ASM for Benchmarks:TestMethod (int) ***
/tmp/.OJH5YA: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <chmarks_TestMethod__int_>:
chmarks_TestMethod__int_():
0: 48 81 ec 88 00 00 00 sub $0x88,%rsp
7: 4c 89 34 24 mov %r14,(%rsp)
b: 48 89 7c 24 78 mov %rdi,0x78(%rsp)
10: 48 b8 78 4e 5f 0c 2f movabs $0x7c2f0c5f4e78,%rax
17: 7c 00 00
1a: f7 00 01 00 00 00 testl $0x1,(%rax)
20: 74 06 je 28 <chmarks_TestMethod__int_+0x28>
22: 90 nop
23: e8 6c a8 f3 ff call fffffffffff3a894 <chmarks_TestMethod__int_+0xfffffffffff3a894>
<BB>:2
28: 33 c0 xor %eax,%eax
2a: 48 89 44 24 68 mov %rax,0x68(%rsp)
2f: 48 89 44 24 70 mov %rax,0x70(%rsp)
34: 49 be 30 01 a7 0c 2f movabs $0x7c2f0ca70130,%r14
3b: 7c 00 00
3e: 33 c0 xor %eax,%eax
40: 48 89 44 24 48 mov %rax,0x48(%rsp)
45: 48 89 44 24 50 mov %rax,0x50(%rsp)
4a: 4d 85 f6 test %r14,%r14
4d: 75 25 jne 74 <chmarks_TestMethod__int_+0x74>
<BB>:15
4f: 33 c0 xor %eax,%eax
51: 48 89 44 24 48 mov %rax,0x48(%rsp)
56: 48 89 44 24 50 mov %rax,0x50(%rsp)
5b: 48 8b 44 24 48 mov 0x48(%rsp),%rax
60: 48 89 44 24 58 mov %rax,0x58(%rsp)
65: 48 8b 44 24 50 mov 0x50(%rsp),%rax
6a: 48 89 44 24 60 mov %rax,0x60(%rsp)
6f: e9 3d 00 00 00 jmp b1 <chmarks_TestMethod__int_+0xb1>
<BB>:14
74: 45 38 36 cmp %r14b,(%r14)
77: 4d 85 f6 test %r14,%r14
7a: 0f 84 e8 00 00 00 je 168 <chmarks_TestMethod__int_+0x168>
80: 49 8d 4e 14 lea 0x14(%r14),%rcx
84: 49 63 46 10 movslq 0x10(%r14),%rax
88: 33 d2 xor %edx,%edx
8a: 48 89 54 24 38 mov %rdx,0x38(%rsp)
8f: 48 89 54 24 40 mov %rdx,0x40(%rsp)
94: 48 89 4c 24 38 mov %rcx,0x38(%rsp)
99: 89 44 24 40 mov %eax,0x40(%rsp)
9d: 48 8b 44 24 38 mov 0x38(%rsp),%rax
a2: 48 89 44 24 58 mov %rax,0x58(%rsp)
a7: 48 8b 44 24 40 mov 0x40(%rsp),%rax
ac: 48 89 44 24 60 mov %rax,0x60(%rsp)
<BB>:11
b1: 48 8b 44 24 58 mov 0x58(%rsp),%rax
b6: 48 89 44 24 28 mov %rax,0x28(%rsp)
bb: 48 8b 44 24 60 mov 0x60(%rsp),%rax
c0: 48 89 44 24 30 mov %rax,0x30(%rsp)
c5: 48 8b 44 24 28 mov 0x28(%rsp),%rax
ca: 48 89 44 24 18 mov %rax,0x18(%rsp)
cf: 48 8b 44 24 30 mov 0x30(%rsp),%rax
d4: 48 89 44 24 20 mov %rax,0x20(%rsp)
d9: 48 8b 4c 24 18 mov 0x18(%rsp),%rcx
de: 48 63 44 24 30 movslq 0x30(%rsp),%rax
e3: ba 02 00 00 00 mov $0x2,%edx
e8: 0f af c2 imul %edx,%eax
eb: 0f 80 67 00 00 00 jo 158 <chmarks_TestMethod__int_+0x158>
f1: 33 d2 xor %edx,%edx
f3: 48 89 54 24 08 mov %rdx,0x8(%rsp)
f8: 48 89 54 24 10 mov %rdx,0x10(%rsp)
fd: 48 89 4c 24 08 mov %rcx,0x8(%rsp)
102: 89 44 24 10 mov %eax,0x10(%rsp)
106: 48 8b 44 24 08 mov 0x8(%rsp),%rax
10b: 48 89 44 24 68 mov %rax,0x68(%rsp)
110: 48 8b 44 24 10 mov 0x10(%rsp),%rax
115: 48 89 44 24 70 mov %rax,0x70(%rsp)
11a: 48 8b 44 24 68 mov 0x68(%rsp),%rax
11f: 48 63 4c 24 78 movslq 0x78(%rsp),%rcx
124: 48 63 c9 movslq %ecx,%rcx
127: 48 63 54 24 70 movslq 0x70(%rsp),%rdx
12c: 48 3b d1 cmp %rcx,%rdx
12f: 0f 86 12 00 00 00 jbe 147 <chmarks_TestMethod__int_+0x147>
135: 48 03 c1 add %rcx,%rax
138: 0f b6 00 movzbl (%rax),%eax
<BB>:1
13b: 4c 8b 34 24 mov (%rsp),%r14
13f: 48 81 c4 88 00 00 00 add $0x88,%rsp
146: c3 ret
147: be 29 00 00 00 mov $0x29,%esi
14c: bf 0b 01 00 00 mov $0x10b,%edi
151: 66 90 xchg %ax,%ax
153: e8 38 2b 5c 01 call 15c2c90 <chmarks_TestMethod__int_+0x15c2c90>
158: be 7d 00 00 00 mov $0x7d,%esi
15d: bf 51 01 00 00 mov $0x151,%edi
162: 90 nop
163: e8 28 2b 5c 01 call 15c2c90 <chmarks_TestMethod__int_+0x15c2c90>
168: be fe 00 00 00 mov $0xfe,%esi
16d: bf 3e 01 00 00 mov $0x13e,%edi
172: 90 nop
173: e8 18 2b 5c 01 call 15c2c90 <chmarks_TestMethod__int_+0x15c2c90>