9prady9 commented on a change in pull request #11674:
URL: https://github.com/apache/arrow/pull/11674#discussion_r748737834
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File path: cpp/src/arrow/util/bitmap_ops.cc
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@@ -237,71 +237,105 @@ bool OptionalBitmapEquals(const std::shared_ptr<Buffer>&
left, int64_t left_offs
namespace {
-template <template <typename> class BitOp>
-void AlignedBitmapOp(const uint8_t* left, int64_t left_offset, const uint8_t*
right,
- int64_t right_offset, uint8_t* out, int64_t out_offset,
- int64_t length) {
+template <template <typename> class BitOp, bool ComputeNewValidityCount>
+int64_t AlignedBitmapOp(const uint8_t* left, int64_t left_offset, const
uint8_t* right,
+ int64_t right_offset, uint8_t* out, int64_t out_offset,
+ int64_t length) {
BitOp<uint8_t> op;
DCHECK_EQ(left_offset % 8, right_offset % 8);
DCHECK_EQ(left_offset % 8, out_offset % 8);
+ uint8_t* outFront = out;
const int64_t nbytes = BitUtil::BytesForBits(length + left_offset % 8);
left += left_offset / 8;
right += right_offset / 8;
out += out_offset / 8;
+ uint64_t outPopCount = 0;
for (int64_t i = 0; i < nbytes; ++i) {
out[i] = op(left[i], right[i]);
}
+ if (ComputeNewValidityCount) {
+ outPopCount = CountSetBits(outFront, out_offset, length);
+ }
+ return outPopCount;
}
-template <template <typename> class BitOp>
-void UnalignedBitmapOp(const uint8_t* left, int64_t left_offset, const
uint8_t* right,
- int64_t right_offset, uint8_t* out, int64_t out_offset,
- int64_t length) {
+template <template <typename> class BitOp, bool ComputeNewValidityCount>
Review comment:
No, there is an performance difference, quite good I would think (first
two columns) - for the aligned code-path. Hence, I added the template bool
expecting the compiler to optimize out the validity count calculation when it
is requested.
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