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Fix undefined behaviour in profile_count::differs_from_p

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This patch avoid overflow in profile_count::differs_from_p and also makes it to
return false from one of the values is undefined while other is defined.

gcc/ChangeLog:

	* profile-count.cc (profile_count::differs_from_p): Fix overflow and
	handling of undefined values.
This commit is contained in:
Jan Hubicka 2023-08-10 18:35:13 +02:00
parent 8afe9d5d2f
commit e41103081b
1 changed files with 3 additions and 2 deletions
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5
gcc/profile-count.cc
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@ -128,13 +128,14 @@ profile_count::differs_from_p (profile_count other) const
{
gcc_checking_assert (compatible_p (other));
if (!initialized_p () || !other.initialized_p ())
return false;
return initialized_p () != other.initialized_p ();
if ((uint64_t)m_val - (uint64_t)other.m_val < 100
|| (uint64_t)other.m_val - (uint64_t)m_val < 100)
return false;
if (!other.m_val)
return true;
int64_t ratio = (int64_t)m_val * 100 / other.m_val;
uint64_t ratio;
safe_scale_64bit (m_val, 100, other.m_val, &ratio);
return ratio < 99 || ratio > 101;
}