BitUtils: __builtin_clz is undefined when value == 0

This commit is contained in:
MerryMage 2021-01-03 17:35:15 +00:00
parent 4b9259d691
commit 6106d6481f
1 changed files with 2 additions and 2 deletions

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@ -365,7 +365,7 @@ T ExpandValue(T value, size_t left_shift_amount)
constexpr int CountLeadingZeros(uint64_t value)
{
#if defined(__GNUC__)
return __builtin_clzll(value);
return value ? __builtin_clzll(value) : 64;
#elif defined(_MSC_VER) && defined(_M_ARM_64)
return _CountLeadingZeros64(value);
#elif defined(_MSC_VER) && defined(_M_X86_64)
@ -385,7 +385,7 @@ constexpr int CountLeadingZeros(uint64_t value)
constexpr int CountLeadingZeros(uint32_t value)
{
#if defined(__GNUC__)
return __builtin_clz(value);
return value ? __builtin_clz(value) : 32;
#elif defined(_MSC_VER) && defined(_M_ARM_64)
return _CountLeadingZeros(value);
#elif defined(_MSC_VER) && defined(_M_X86_64)