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Replace check_mul_overflow_size_t with __builtin_mul_overflow
Checked on x86_64-linux-gnu and i686-linux-gnu. * malloc/alloc_buffer_alloc_array.c (__libc_alloc_buffer_alloc_array): Use __builtin_mul_overflow in place of check_mul_overflow_size_t. * malloc/dynarray_emplace_enlarge.c (__libc_dynarray_emplace_enlarge): Likewise. * malloc/dynarray_resize.c (__libc_dynarray_resize): Likewise. * malloc/reallocarray.c (__libc_reallocarray): Likewise. * malloc/malloc-internal.h (check_mul_overflow_size_t): Remove function. * support/blob_repeat.c (check_mul_overflow_size_t, (minimum_stride_size, support_blob_repeat_allocate): Likewise.
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@ -74,24 +74,4 @@ void __malloc_fork_unlock_child (void) attribute_hidden;
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/* Called as part of the thread shutdown sequence. */
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void __malloc_arena_thread_freeres (void) attribute_hidden;
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/* Set *RESULT to LEFT * RIGHT. Return true if the multiplication
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overflowed. */
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static inline bool
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check_mul_overflow_size_t (size_t left, size_t right, size_t *result)
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{
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#if __GNUC__ >= 5
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return __builtin_mul_overflow (left, right, result);
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#else
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/* size_t is unsigned so the behavior on overflow is defined. */
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*result = left * right;
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size_t half_size_t = ((size_t) 1) << (8 * sizeof (size_t) / 2);
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if (__glibc_unlikely ((left | right) >= half_size_t))
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{
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if (__glibc_unlikely (right != 0 && *result / right != left))
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return true;
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}
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return false;
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#endif
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}
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#endif /* _MALLOC_INTERNAL_H */
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