[mlir][Linalg] Use unsigned return type for RelayoutOp::getSourceRank,getDestRank

[tblah]

Summary

Since https://reviews.llvm.org/D142053, building mlir with clang using -Werror
fails reporting comparison of integers with different signs.

Fix this by using (unsigned) size_t instead of (signed) int64_t for comparisons
with other size_t values.

[chelini]

Agree, let's fix getSourceRank and getDestRank. The change should be simple: https://github.com/llvm/llvm-project/blob/b0d575310f2ee660dadfdaf1e06bac148a575754/mlir/include/mlir/Dialect/Tensor/IR/TensorOps.td#L1670 Do you want to give it a try?

[tblah]

Updated getSourceRank and getDestRank to return size_t to avoid comparison
between int64_t and size_t.

[chelini]

Thank you! Mind updating the summary and title? After that, for me, you can land it.

mlir/include/mlir/Dialect/Tensor/IR/TensorOps.td

class Tensor_RelayoutOp<string mnemonic, list<Trait> traits = []> :
         DestinationStyleOpInterface,
         ConditionallySpeculatable, NoMemoryEffect,
         DeclareOpInterfaceMethods<ReifyRankedShapedTypeOpInterface>,
         TypesMatchWith<"result type matches type of dest",
                    "dest", "result",
                    "$_self">])> {
 
   code commonExtraClassDeclaration = [{
-    int64_t getSourceRank() { return getSource().getType().getRank(); };
-    int64_t getDestRank() { return getDest().getType().getRank(); };
+    size_t getSourceRank() { return getSource().getType().getRank(); };
+    size_t getDestRank() { return getDest().getType().getRank(); };
     RankedTensorType getSourceType() {
       return getSource().getType().cast<RankedTensorType>(); };
     RankedTensorType getDestType() {
       return getDest().getType().cast<RankedTensorType>(); };
 
     /// Return position for init operand. Init operand is `dest`.
     std::pair<int64_t, int64_t> getDpsInitsPositionRange() {
       return {1, 2}; // `dest` operand

mlir/lib/Dialect/Linalg/TransformOps/LinalgTransformOps.cpp

 bool isValidPackingPermutation(
     RelayoutOpTy op, ArrayRef<int64_t> permutation,
     OuterOrInnerPerm outerOrInnerPerm = OuterOrInnerPerm::Outer) {
   static_assert(
       llvm::is_one_of<RelayoutOpTy, tensor::PackOp, tensor::UnPackOp>::value,
       "applies to only pack or unpack operations");
   if (!op || permutation.empty())
     return true;
-  int64_t innerRank = op.getInnerDimsPos().size();
+  size_t innerRank = op.getInnerDimsPos().size();
   if (outerOrInnerPerm == OuterOrInnerPerm::Inner)
     return permutation.size() == innerRank && isPermutationVector(permutation);
   // op.getOuterDimsPerm() may be empty, in which case it is identity.
   // Don't rely on it.
   if (std::is_same<RelayoutOpTy, tensor::PackOp>::value) {
     return permutation.size() == op.getSourceRank() &&
            isPermutationVector(permutation);
   }