[mlir][vector] NFC - Add rewriter.notifyMatchFailure messages for better debugging

[nicolasvasilache]

Summary

Add rewriter.notifyMatchFailure messages for better debugging

[ThomasRaoux]

nice :)

mlir/lib/Dialect/Vector/Transforms/VectorTransforms.cpp

struct TransferWriteToVectorStoreLowering
   TransferWriteToVectorStoreLowering(MLIRContext *context,
                                      llvm::Optional<unsigned> maxRank)
       : OpRewritePattern<vector::TransferWriteOp>(context),
         maxTransferRank(maxRank) {}
 
   LogicalResult matchAndRewrite(vector::TransferWriteOp write,
                                 PatternRewriter &rewriter) const override {
     if (maxTransferRank && write.getVectorType().getRank() > *maxTransferRank)
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "rank exceeds maxTransferRank: " << write;
+      });
 
     // Permutations are handled by VectorToSCF or
     // populateVectorTransferPermutationMapLoweringPatterns.
     if ( // pass-through for the 0-d corner case.
         !write.getPermutationMap().isMinorIdentity())
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "permutation map is not minor identity: " << write;
+      });
 
     auto memRefType = write.getShapedType().dyn_cast<MemRefType>();
     if (!memRefType)
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "not a memref type: " << write;
+      });
 
     // Non-unit strides are handled by VectorToSCF.
     if (!vector::isLastMemrefDimUnitStride(memRefType))
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "most minor stride is not 1: " << write;
+      });
 
     // `vector.store` supports vector types as memref's elements only when the
     // type of the vector value being written is the same as the element type.
     auto memrefElTy = memRefType.getElementType();
     if (memrefElTy.isa<VectorType>() && memrefElTy != write.getVectorType())
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "elemental type mismatch: " << write;
+      });
 
     // Otherwise, element types of the memref and the vector must match.
     if (!memrefElTy.isa<VectorType>() &&
         memrefElTy != write.getVectorType().getElementType())
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "elemental type mismatch: " << write;
+      });
 
     // Out-of-bounds dims are handled by MaterializeTransferMask.
     if (write.hasOutOfBoundsDim())
-      return failure();
+      return rewriter.notifyMatchFailure(write.getLoc(), [=](Diagnostic &diag) {
+        diag << "out of bounds dim: " << write;
+      });
     if (write.getMask()) {
       rewriter.replaceOpWithNewOp<vector::MaskedStoreOp>(
           write, write.getSource(), write.getIndices(), write.getMask(),
           write.getVector());
     } else {
       rewriter.replaceOpWithNewOp<vector::StoreOp>(
           write, write.getVector(), write.getSource(), write.getIndices());
     }