HappenLee commented on code in PR #68308:
URL: https://github.com/apache/doris/pull/68308#discussion_r4060678577
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be/src/exprs/vcompound_pred.h:
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@@ -625,7 +625,8 @@ class VCompoundPred : public VectorizedFnCall {
if constexpr (is_and) {
lhs[i] &= rhs[i];
} else {
- lhs[i] |= rhs[i];
+ // Logical OR must produce a canonical Boolean instead of
preserving input bits.
+ lhs[i] = (lhs[i] != 0) || (rhs[i] != 0);
Review Comment:
Please use `(lhs[i] | rhs[i]) != 0` here to retain efficient SIMD while
still producing canonical Boolean bytes.
For two non-constant, non-nullable Boolean columns containing mixed
TRUE/FALSE values, the whole-column shortcuts do not apply and execution
reaches this loop. With Clang 16.0.6 and 21.1.8 (`-O3 -DNDEBUG -mavx2`), I
extracted the loop including its `__restrict` qualifiers and vectorization
pragma. The `||` form is reported as vectorized, but its conditional RHS loads
lower to many per-byte branches and vector extract/insert operations. The
proposed expression instead generates packed OR, compare-to-zero, and mask
operations without per-row conditional branches.
A local kernel microbenchmark on a Xeon Platinum 8457C (8,192 rows × 8,192
iterations, pinned to one CPU; median of three trials with rotated measurement
order, Clang 21) measured:
- Original bitwise OR: **1.51 ms**
- Current logical OR: **44.39 ms**
- Bitwise OR followed by `!= 0`: **1.87 ms**
These are loop timings, not end-to-end SQL timings. I also exhaustively
checked all 65,536 UInt8 input pairs: the proposed expression is equivalent to
the current normalization and always returns 0 or 1.
```suggestion
lhs[i] = (lhs[i] | rhs[i]) != 0;
```
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