shufti-double: fix regressions from #325#368
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byeonguk-jeong wants to merge 4 commits intoVectorCamp:developfrom
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shufti-double: fix regressions from #325#368byeonguk-jeong wants to merge 4 commits intoVectorCamp:developfrom
byeonguk-jeong wants to merge 4 commits intoVectorCamp:developfrom
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run_accel() passed c_end - 1 to shuftiDoubleExec(). shuftiDoubleExecReal already handles the last-byte boundary internally via check_last_byte(), so shortening the buffer caused it to miss valid matches near the end and apply the wildcard check to the wrong byte. Changed to pass c_end. Fixes: ca70a3d ("Fix double shufti's vector end false positive (VectorCamp#325)") Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>
first_char_mask was reset to Ones() after the peel-off block, discarding carry-over state for cross-boundary pattern detection. Remove the reset. Fixes: ca70a3d ("Fix double shufti's vector end false positive (VectorCamp#325)") Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>
loop condition i > 2 missed the final vshr(1), leaving odd-indexed bytes out of the reduce. Use i >= 2. Fixes: ca70a3d ("Fix double shufti's vector end false positive (VectorCamp#325)") Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>
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Test failures on AVX512 are fixed at #373. It is not related to these commits. |
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Aside the assumption of vector size in the test, LGTM. Thanks for the fix.
Add three tests exercising the double shufti edge cases.
- ExecMatchVectorEdge: Two-byte pair ("ab") spanning the peel-off to
aligned block boundary is correctly detected. Validates that
first_char_mask state carries over and is not reset after peel-off.
- ExecNoMatchLastByte: First character of a double-byte pair ('x' from
"xy") at the last buffer byte does not cause a false positive when
the second character is absent.
- ExecMatchLastByte: Single-byte pattern ('a') at the last buffer byte
is detected via check_last_byte's reduce.
Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>
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As reported in BUG: scanning returns no matches with multi-pattern database; but minimal set still matches #358, Fix double shufti's vector end false positive #325 introduced a false negative. The caller side told the buffer length as c_end - 1, so that shuftiDoubleExec() unexpectedly tried to match the byte before the last byte with single char patterns.
check_last_byte() reduces the mask to make a wildcard mask, which matches any character that could match as the second byte of a double-byte pattern. However, the loop condition i > 2 skipped the final vshr(1) step, causing only even-indexed bytes to be folded into the reduce result.
After peel-off stage for alignment, the carry-over state was discarded.
Add some unit tests for this fixes.
@AhnLab-OSS @AhnLab-OSSG