message: Downgrade some emitErrors in patterns to notifyMatchFailure.
diff: @@ -245,10 +245,8 @@ class PointwiseToLinalgConverter : public OpConversionPattern<OpTy> {
  return fail(this->typeConverter->convertType(t)
  .template dyn_cast<ShapedType>());
  })) {
  - return emitError(loc,
  - "hlo to linalg conversion expects ranked args of "
  - "signless int, float or complex element type with ")
  - << nloops << " parallel iterators: " << *(op.getOperation());
  + return rewriter.notifyMatchFailure(
  + op, "mismatched operand/result types or iterator count");
  }
  // Construct the indexing maps needed for linalg.generic ops.
  @@ -1095,8 +1093,7 @@ class ReduceConverter : public OpConversionPattern<lmhlo::ReduceOp> {
  auto operand_shape =
  adaptor.inputs()[0].getType().template dyn_cast<ShapedType>();
  if (!operand_shape || !operand_shape.hasRank()) {
  - emitError(loc, "lhlo to linalg conversion expects known-rank args");
  - return failure();
  + return rewriter.notifyMatchFailure(reduce_op, "expects known-rank args");
  }
  // First fill the output buffer with the init value.
  @@ -1216,8 +1213,7 @@ class SliceConverter : public OpConversionPattern<OpTy> {
  auto loc = slice_op.getLoc();
  auto arg_type = args[0].getType().template dyn_cast<ShapedType>();
  if (!arg_type || !arg_type.hasRank()) {
  - emitError(loc, "lhlo to linalg conversion expects known-rank args");
  - return failure();
  + return rewriter.notifyMatchFailure(slice_op, "expects known-rank args");
  }
  SmallVector<OpFoldResult, 3> offsets, sizes, strides;
  