[Mlir-commits] [mlir] [MLIR][SCF] fix loop pipelining pass use of uninitialized value (PR #146991)

[Hu Yufan]

Hyffer wrote:

The two failed cases in `Dialect/SCF/transform-ops.mlir` are both corner cases that `numIteration == maxStage`. In those cases, loops are able to properly pipelined, with a pipeline kernel that iterates for zero time, looks like:
```
S0(0)                        
S0(1) S1(0)                  
scf.for ... to ... {            <-- which will iterates for zero time
  S0(I+2) S1(I+1) S2(I)      
}
S1(N) S2(N-1)                
S2(N)                        
```

Test itself is correct. I have updated the condition. @ThomasRaoux could you have a review on that?

```
********************
Failed Tests (2):
  MLIR-Unit :: Target/LLVM/./MLIRTargetLLVMTests/MLIRTargetLLVMROCDL/GetELFMetadata
  MLIR-Unit :: Target/LLVM/./MLIRTargetLLVMTests/MLIRTargetLLVMROCDL/SerializeROCDLToBinary


Testing Time: 12.77s

Total Discovered Tests: 3332
  Skipped          :    1 (0.03%)
  Unsupported      :  458 (13.75%)
  Passed           : 2870 (86.13%)
  Expectedly Failed:    1 (0.03%)
  Failed           :    2 (0.06%)
```

https://github.com/llvm/llvm-project/pull/146991