| Issue |
61400
|
| Summary |
[WASM] Suboptimal `memcmp` expansion for odd lengths
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
MaxGraey
|
# Example ([godbolt](https://godbolt.org/z/jMo4f9G18))
Calls to `memcmp(a, b, n) == 0`, where `n` is odd is suboptimal for `wasm32` target where such call didn't lower to expansion and calls `memcpy` routine even for small lengths (`n` <= 14)
Here codegen for `memcmp(a, "abc", 3) == 0`:
### x64
```asm
movzx eax, word ptr [rdi]
xor eax, 25185
movzx ecx, byte ptr [rdi + 2]
xor ecx, 99
or cx, ax
sete al
ret
```
### wasm32
```wat
local.get 0
i32.const .L.str.2
i32.const 3
call memcmp
i32.eqz
```
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