| Issue |
154000
|
| Summary |
Missed optimization: eliminate redundant range check
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
zxt5
|
```
define i1 @src(ptr %arg0) {
%v0 = load i8, ptr %arg0, align 8
%v1 = icmp ugt i8 %v0, 28
%v2 = and i8 %v0, -2
%v3 = icmp eq i8 %v2, 48
%v4 = and i1 %v1, %v3
ret i1 %v4
}
define i1 @tgt(ptr %arg0) {
%v0 = load i8, ptr %arg0, align 8
%v2 = and i8 %v0, -2
%v3 = icmp eq i8 %v2, 48
ret i1 %v3
}
```
Alive2: https://alive2.llvm.org/ce/z/PizgLm
Godbolt: https://godbolt.org/z/4aezssq38
Found the pattern in https://github.com/dtcxzyw/llvm-opt-benchmark/blob/main/bench/llvm/optimized/InstCombineCompares.ll
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