| Issue |
166882
|
| Summary |
Missed Optimization: Fold boolean-indexed array GEP into select of base vs. element pointer
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
Leo0506
|
```
define ptr @src(i32 %arg1, ptr %arg0) {
%v0 = add i32 %arg1, -1
%v1 = icmp ne i32 %v0, 0
%v2 = zext i1 %v1 to i64
%v3 = getelementptr [2 x ptr], ptr %arg0, i64 0, i64 %v2
ret ptr %v3
}
define ptr @tgt(i32 %arg1, ptr %arg0) {
%v0 = icmp eq i32 %arg1, 1
%v1 = getelementptr [2 x ptr], ptr %arg0, i64 0, i64 1
%v2 = select i1 %v0, ptr %arg0, ptr %v1
ret ptr %v2
}
```
alive2: https://alive2.llvm.org/ce/z/7Z-Z-Q
godbolt: https://godbolt.org/z/9asvWEPsP
Pattern found in: https://github.com/dtcxzyw/llvm-opt-benchmark/blob/main/bench/linux/optimized/gen8_ppgtt.ll
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