[mlir] Add helpers to set lbs, ubs, steps for linalg.tiled_loop.

[gysit]

LGTM except for the set steps assertion message

mlir/include/mlir/Dialect/Linalg/IR/LinalgOps.td

614

steps?

mlir/include/mlir/Dialect/Linalg/IR/LinalgOps.td

def Linalg_TiledLoopOp : Linalg_Op<"tiled_loop", [
   let extraClassDeclaration = [{
     /// Number of operands controlling the loop: lbs, ubs, steps
     unsigned getNumControlOperands() { return 3 * getNumLoops(); }
 
     ValueRange getInductionVars() {
       return getBody()->getArguments();
     }
 
+
+    void setLowerBounds(ValueRange lowerBounds) {
+      unsigned numLoops = getNumLoops();
+      assert(lowerBounds.size() == numLoops &&
+             "expected lower bounds for every loop dimension");
+      for (unsigned i = 0; i < numLoops; ++i)
+        setOperand(i, lowerBounds[i]);
+    }
+
+    void setUpperBounds(ValueRange upperBounds) {
+      unsigned numLoops = getNumLoops();
+      assert(upperBounds.size() == numLoops &&
+             "expected upper bounds for every loop dimension");
+      for (unsigned i = 0, pos = numLoops; i < numLoops; ++i, ++pos)
+        setOperand(pos, upperBounds[i]);
+    }
+
+    void setSteps(ValueRange steps) {
+      unsigned numLoops = getNumLoops();
+      assert(steps.size() == numLoops &&
+             "expected upper bounds for every loop dimension");
+      for (unsigned i = 0, pos = 2 * numLoops; i < numLoops; ++i, ++pos)
+        setOperand(pos, steps[i]);
+    }
+
    /// Result that corresponds to the `outputs` argument of tensor type.
    OpResult getTiedOpResult(OpOperand& opOperand) {
       // No result can correspond to a memref argument.
       if (opOperand.get().getType().isa<MemRefType>()) return OpResult();
 
       // Check whether the operand index is in bounds of `outputs()` arg.
       int operandIndex = opOperand.getOperandNumber();
       int outputIndexStart =