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author | das <das@FreeBSD.org> | 2009-01-31 18:27:02 +0000 |
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committer | das <das@FreeBSD.org> | 2009-01-31 18:27:02 +0000 |
commit | 61dc3e056cc2ad51f33f296f1cfda0ece440b85e (patch) | |
tree | 86563ca98ba62d850839a916a23d185416bda1b7 /include/stdlib.h | |
parent | fb1404080f89a63cdf36da668e5ff4fc65cfa4d9 (diff) | |
download | FreeBSD-src-61dc3e056cc2ad51f33f296f1cfda0ece440b85e.zip FreeBSD-src-61dc3e056cc2ad51f33f296f1cfda0ece440b85e.tar.gz |
Add a function attribute called `__malloc_like', which informs gcc
that the annotated function returns a pointer that doesn't alias any
extant pointer. This results in a 50%+ speedup in microbenchmarks such
as the following:
char *cp = malloc(1), *buf = malloc(BUF);
for (i = 0; i < BUF; i++) buf[i] = *cp;
In real programs, your mileage will vary. Note that gcc already
performs this optimization automatically for any function called
`malloc', `calloc', `strdup', or `strndup' unless -fno-builtins is
used.
Diffstat (limited to 'include/stdlib.h')
-rw-r--r-- | include/stdlib.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/stdlib.h b/include/stdlib.h index 0a83270..91be536 100644 --- a/include/stdlib.h +++ b/include/stdlib.h @@ -88,14 +88,14 @@ int atoi(const char *); long atol(const char *); void *bsearch(const void *, const void *, size_t, size_t, int (*)(const void *, const void *)); -void *calloc(size_t, size_t); +void *calloc(size_t, size_t) __malloc_like; div_t div(int, int) __pure2; void exit(int) __dead2; void free(void *); char *getenv(const char *); long labs(long) __pure2; ldiv_t ldiv(long, long) __pure2; -void *malloc(size_t); +void *malloc(size_t) __malloc_like; int mblen(const char *, size_t); size_t mbstowcs(wchar_t * __restrict , const char * __restrict, size_t); int mbtowc(wchar_t * __restrict, const char * __restrict, size_t); |