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Fixing invalid prefetch pointers #628

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Fixing invalid prefetch pointers #628

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3 changes: 0 additions & 3 deletions CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -197,9 +197,6 @@ if(HNSWLIB_EXAMPLES)
if(ENABLE_MSAN)
add_cxx_flags(-fsanitize=memory)
endif()
if(ENABLE_ASAN OR ENABLE_UBSAN)
add_cxx_flags(-DHNSWLIB_USE_PREFETCH=0)
endif()

add_cxx_flags(-Wall -Wextra -Wpedantic -Werror)

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18 changes: 12 additions & 6 deletions hnswlib/hnswalg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -283,8 +283,10 @@ class HierarchicalNSW : public AlgorithmInterface<dist_t> {
// if (candidate_id == 0) continue;
#ifdef USE_SSE
#if HNSWLIB_USE_PREFETCH
_mm_prefetch((char *) (visited_array + *(datal + j + 1)), _MM_HINT_T0);
_mm_prefetch(getDataByInternalId(*(datal + j + 1)), _MM_HINT_T0);
if (j + 1 < size) {
_mm_prefetch((char *) (visited_array + *(datal + j + 1)), _MM_HINT_T0);
_mm_prefetch(getDataByInternalId(*(datal + j + 1)), _MM_HINT_T0);
}
#endif
#endif
if (visited_array[candidate_id] == visited_array_tag) continue;
Expand Down Expand Up @@ -393,9 +395,11 @@ class HierarchicalNSW : public AlgorithmInterface<dist_t> {
// if (candidate_id == 0) continue;
#ifdef USE_SSE
#if HNSWLIB_USE_PREFETCH
_mm_prefetch((char *) (visited_array + *(data + j + 1)), _MM_HINT_T0);
_mm_prefetch(data_level0_memory_ + (*(data + j + 1)) * size_data_per_element_ + offsetData_,
_MM_HINT_T0); ////////////
if (j + 1 < size) {
_mm_prefetch((char *) (visited_array + *(data + j + 1)), _MM_HINT_T0);
_mm_prefetch(data_level0_memory_ + (*(data + j + 1)) * size_data_per_element_ + offsetData_,
_MM_HINT_T0);
}
#endif
#endif
if (!(visited_array[candidate_id] == visited_array_tag)) {
Expand Down Expand Up @@ -1126,7 +1130,9 @@ class HierarchicalNSW : public AlgorithmInterface<dist_t> {
for (int i = 0; i < size; i++) {
#ifdef USE_SSE
#if HNSWLIB_USE_PREFETCH
_mm_prefetch(getDataByInternalId(*(datal + i + 1)), _MM_HINT_T0);
if (i + 1 < size) {
_mm_prefetch(getDataByInternalId(*(datal + i + 1)), _MM_HINT_T0);
}
#endif
#endif
tableint cand = datal[i];
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