Fixed Kenneth's PHP bug in max/min - was an aliasing bug in sse #56
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Can you merge it with latest master so it can be pulled clean? |
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Could you add a small comment explaining why it had aliasing issues. I just got it explained by Kristian, but it is not easy to read from the source. |
| @@ -843,7 +843,7 @@ size_t Array::FirstSetBit64(int64_t v) const | |||
| if ((w == 8 || w == 16 || w == 32) && end - start > 2 * sizeof(__m128i) * 8 / NO0(w)) { | |||
| __m128i *data = (__m128i *)(m_data + start * w / 8); | |||
| __m128i state = data[0]; | |||
| __m128i state2; | |||
| char state2[sizeof(state)]; | |||
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I'm pretty sure that changing the type of state2 has no effect on the aliasing issue. I believe what fixes the aliasing bug is the fact that memcpy() modifies state2 as though it was a character array. I would love to see what happens when reverting state2 back to __m128i. Hopefully nothing.
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Please ignore my comments on aliasing. My theory turned out to be wrong.
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+1 |
…ryspeed Conflicts: TightDB.vcxproj src/tightdb/alloc_slab.cpp src/tightdb/alloc_slab.hpp test/transactions.cpp
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I've fixed this by modifying our masterbranch directly and bypassed this pull requst. |
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