+/*
+ * fls: find last set bit.
+ *
+ * Returns the 1-based index of the most-significant bit in x. The MSB
+ * is bit number 32, the LSB is bit number 1. If x is zero, the result is
+ * undefined.
+ */
+static inline int
+fls(unsigned int x)
...
+ idx = fls((size - 1) >> ALLOC_MINBITS);
If size <= 8, fls((size - 1) >> ALLOC_MINBITS) is fls(0).
The result of fls(0) is undefined.
I think we have to never call fls(0) from AllocSetFreeIndex().
My proposal code:
if (size > (1 << ALLOC_MINBITS))
{
idx = fls((size - 1) >> ALLOC_MINBITS);
Assert(idx < ALLOCSET_NUM_FREELISTS);
}
Best regards,
---
Atsushi Ogawa
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