llvm-project

d31eaf18 - [mlir] Add splitForOpAtBound utility and use it in loop unrolling (#215108)

[mlir] Add splitForOpAtBound utility and use it in loop unrolling (#215108) ## Summary Adds `splitForOpAtPoint` to split an `scf.for` at a given split point: - first loop: `[lowerBound, splitPoint)` - second loop: `[splitPoint, upperBound)` The original loop is not mutated in place. Two new loops are cloned, iter-args are chained from the first to the second, uses of the original results are rewired, and the original op is erased. The helper returns `{first, second}`. The split point is validated as: - `lowerBound <= splitPoint < upperBound` - `step > 0` - `splitPoint == lowerBound + k * step` When the needed values are constant, an invalid split fails at compile time. When any of them is dynamic, the same conditions are emitted as runtime `arith.cmpi` / `cf.assert`. Signed vs unsigned follows the loop's `unsignedCmp` attribute (`getConstantIntValue` / `getConstantUIntValue`). `loopUnrollByFactor` uses this helper for the epilogue instead of inlining clone-and-rewire logic. The first returned loop is the main loop to unroll; the second is the epilogue. Also adds `getConstantUIntValue` (zero-extend to `uint64_t`) next to `getConstantIntValue`, and links the ControlFlow dialect from SCF Utils so runtime asserts can be created. --------- Co-authored-by: Cursor <cursoragent@cursor.com>