| Issue |
173408
|
| Summary |
[X86] Missed combining of `adc` + `add` with constant arguments
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
UniQP
|
For the following code, the generated `adc` and `add` instructions can be combined into a single `adc` instruction.
Compiler explorer: https://godbolt.org/z/95v4x53Ef
```llvm
define i32 @test(i32 %0, i32 %1, i32 %2) {
%4 = icmp ult i32 %0, %1
%5 = zext i1 %4 to i32
%6 = add i32 %2, 42
%7 = add i32 %6, %5
%8 = icmp slt i32 %7, 0
%9 = select i1 %8, i32 %1, i32 %0
ret i32 %9
}
```
Output:
```assembly
test:
mov eax, edi
cmp edi, esi
adc edx, 0
add edx, 42
cmovs eax, esi
ret
```
Expected:
```assembly
test:
mov eax, edi
cmp edi, esi
adc edx, 42
cmovs eax, esi
ret
```
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