From ae0f99f6244432b1d2ee7e45e263ad91ea6bc82d Mon Sep 17 00:00:00 2001 From: David Rowley Date: Thu, 6 Nov 2025 23:29:27 +1300 Subject: [PATCH v2 2/2] Adjust MemSet macro to use size_t rather than long Likewise for MemSetAligned. long wasn't the most suitable type for these macros as MSVC in 64-bit builds has sizeof(long) == 4, which is narrower than the processor's word size, therefore these macros had to perform twice as many loops as they otherwise might. Author: David Rowley Reviewed-by: Heikki Linnakangas Reviewed-by: Peter Eisentraut Discussion: https://postgr.es/m/CAApHDvoGFjSA3aNyVQ3ivbyc4ST=CC5L-_VjEUQ92HbE2Cxovg@mail.gmail.com --- src/include/c.h | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-) diff --git a/src/include/c.h b/src/include/c.h index 757dfff4782..cb8a38669be 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -1007,29 +1007,29 @@ pg_noreturn extern void ExceptionalCondition(const char *conditionName, #define Min(x, y) ((x) < (y) ? (x) : (y)) -/* Get a bit mask of the bits set in non-long aligned addresses */ -#define LONG_ALIGN_MASK (sizeof(long) - 1) +/* Get a bit mask of the bits set in non-size_t aligned addresses */ +#define SIZE_T_ALIGN_MASK (sizeof(size_t) - 1) /* * MemSet * Exactly the same as standard library function memset(), but considerably - * faster for zeroing small word-aligned structures (such as parsetree nodes). - * This has to be a macro because the main point is to avoid function-call - * overhead. However, we have also found that the loop is faster than - * native libc memset() on some platforms, even those with assembler - * memset() functions. More research needs to be done, perhaps with - * MEMSET_LOOP_LIMIT tests in configure. + * faster for zeroing small size_t-aligned structures (such as parsetree + * nodes). This has to be a macro because the main point is to avoid + * function-call overhead. However, we have also found that the loop is + * faster than native libc memset() on some platforms, even those with + * assembler memset() functions. More research needs to be done, perhaps + * with MEMSET_LOOP_LIMIT tests in configure. */ #define MemSet(start, val, len) \ do \ { \ - /* must be void* because we don't know if it is integer aligned yet */ \ + /* must be void* because we don't know if it is size_t aligned yet */ \ void *_vstart = (void *) (start); \ int _val = (val); \ Size _len = (len); \ \ - if ((((uintptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \ - (_len & LONG_ALIGN_MASK) == 0 && \ + if ((((uintptr_t) _vstart) & SIZE_T_ALIGN_MASK) == 0 && \ + (_len & SIZE_T_ALIGN_MASK) == 0 && \ _val == 0 && \ _len <= MEMSET_LOOP_LIMIT && \ /* \ @@ -1038,8 +1038,8 @@ pg_noreturn extern void ExceptionalCondition(const char *conditionName, */ \ MEMSET_LOOP_LIMIT != 0) \ { \ - long *_start = (long *) _vstart; \ - long *_stop = (long *) ((char *) _start + _len); \ + size_t *_start = (size_t *) _vstart; \ + size_t *_stop = (size_t *) ((char *) _start + _len); \ while (_start < _stop) \ *_start++ = 0; \ } \ @@ -1049,23 +1049,23 @@ pg_noreturn extern void ExceptionalCondition(const char *conditionName, /* * MemSetAligned is the same as MemSet except it omits the test to see if - * "start" is word-aligned. This is okay to use if the caller knows a-priori - * that the pointer is suitably aligned (typically, because he just got it - * from palloc(), which always delivers a max-aligned pointer). + * "start" is size_t-aligned. This is okay to use if the caller knows + * a-priori that the pointer is suitably aligned (typically, because he just + * got it from palloc(), which always delivers a max-aligned pointer). */ #define MemSetAligned(start, val, len) \ do \ { \ - long *_start = (long *) (start); \ + size_t *_start = (size_t *) (start); \ int _val = (val); \ Size _len = (len); \ \ - if ((_len & LONG_ALIGN_MASK) == 0 && \ + if ((_len & SIZE_T_ALIGN_MASK) == 0 && \ _val == 0 && \ _len <= MEMSET_LOOP_LIMIT && \ MEMSET_LOOP_LIMIT != 0) \ { \ - long *_stop = (long *) ((char *) _start + _len); \ + size_t *_stop = (size_t *) ((char *) _start + _len); \ while (_start < _stop) \ *_start++ = 0; \ } \ -- 2.43.0