Don't use std::popcount (workaround) #8098
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It seems MSVC uses POPCNT instruction when compiling for SSE2.
elad335
reviewed
Apr 25, 2020
| @@ -1182,7 +1182,7 @@ namespace vm | |||
| if (is_write) | |||
| std::swap(src, dst); | |||
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| if (size <= 16 && std::popcount(size) == 1 && (addr & (size - 1)) == 0) | |||
| if (size <= 16 && (size & (size - 1)) == 0 && (addr & (size - 1)) == 0) | |||
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Suggested change
| if (size <= 16 && (size & (size - 1)) == 0 && (addr & (size - 1)) == 0) | |
| if (size <= 16 && ((size | addr) & (size - 1)) == 0) |
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There is little point to optimize it by hand (the outcome is the same), it only hurts readability due to mixing two different checks.
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Should address #8085