[mlir][linalg] Fix Linalg runtime verification pass to handle tensors with dimensions of size 0 (#163791)
Runtime verification on Linalg structured ops unconditionally computed
`end - 1` to determine the last iteration index before composing
indexing maps. This caused spurious "negative index" assertion failures
while operating on empty tensors (tensors with a dimension of size 0).
The issue occurs because:
1. Empty tensors create loop ranges [0, 0) with zero trip count
2. Computing end - 1 = 0 - 1 = -1 creates a fictitious negative index
3. The negative index check triggers even though no loop iterations
occur
The fix is to guard all runtime verification with a check that ensures
all loop ranges are non-empty (start < end) before performing any index
arithmetic.
Example MLIR that previously failed:
```mlir
func.func @fill_empty() -> tensor<0xi32> {
%c0 = arith.constant 0 : i32
%empty = tensor.empty() : tensor<0xi32>
%filled = linalg.fill ins(%c0 : i32) outs(%empty : tensor<0xi32>) -> tensor<0xi32>
return %filled : tensor<0xi32>
}
```
---------
Co-authored-by: Hanumanth Hanumantharayappa <hhanuman@ah-hhanuman-l.dhcp.mathworks.com>Welcome to the LLVM project!
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