Simplify validate_utf16be for icelake and rvv
#777
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We really need the most significant byte to validate UTF-16, full endianess conversion is not needed.
We really need the most significant byte to validate UTF-16, full endianess conversion is not needed. Manually checked that the generated for both UTF-16le and UTF-16be validation is exactly the same.
lemire
approved these changes
May 1, 2025
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We need only inspect most significant byte. In the case of icelake kernel
pshufbis replaced with shift --- it's not a big change, just noticed that AMD Zen4 has latency 1 cycle for shift , and 2 cycles for pshufb.In the case of rvv we completely rid of endianness changing, resulting in the same code for LE and BE variants.