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gh-157906: fix an incorrect architecture macro check in free-threaded GC #157907

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gh-157906: fix an incorrect architecture macro check in free-threaded GC #157907

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2e83bef
fix typo in free-threaded GC prefetch check for 32-bit MSVC
lpyu001 Sep 21, 2026
5b14842
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lpyu001 Sep 22, 2026
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Windows/2026-09-21-20-54-37.gh-issue-157906.RlyLkY.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix an incorrect architecture macro check that prevented CPU prefetching in
the free-threaded garbage collector on 32-bit Windows builds.
2 changes: 1 addition & 1 deletion Python/gc_free_threading.c
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Expand Up @@ -548,7 +548,7 @@ static_assert(BUFFER_HI < BUFFER_SIZE &&
#define PREFETCH_T1(ptr) __builtin_prefetch(ptr, 0, 2)
#define PREFETCH_T2(ptr) __builtin_prefetch(ptr, 0, 1)
#define PREFETCH_NTA(ptr) __builtin_prefetch(ptr, 0, 0)
#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) && !defined(_M_ARM64EC)
#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_IX86)) && !defined(_M_ARM64EC)
#include <mmintrin.h>
#define PREFETCH_T0(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T0)
#define PREFETCH_T1(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1)
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