gh-126024: Use only memcpy for unaligned loads in find_first_nonascii#127769
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encukou wants to merge 1 commit intopython:mainfrom
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gh-126024: Use only memcpy for unaligned loads in find_first_nonascii#127769encukou wants to merge 1 commit intopython:mainfrom
encukou wants to merge 1 commit intopython:mainfrom
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Did you benchmarked it? |
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result: current implementation uses switch+union, but switch+shift might be better because we use clang for JIT. |
methane
reviewed
Dec 10, 2024
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| // less than size_t bytes left. | ||
| assert(end - p <= SIZEOF_SIZE_T); |
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This assertion would fail when not PY_LITTLE_ENDIAN && HAVE_CTZ case.
// big endian and minor compilers are difficult to test.
// fallback to per byte check.
break;
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Ah, my benchmark was flawed. Sorry for the noise! |
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Sorry for getting to this late.
GH-126025 optimized the UTF-8 decoder with a fast
find_first_nonasciifunction.GH-127566 then fixed an alignment issue by switching one case to
memcpy-- on all platforms, even those that used theload_unalignedhelper (which does a byte-by-byte copy), tomemcpy.This switches the remaining
load_unalignedcall tomemcpy, and removes the now-unused helper.