On 06/29/2017 10:15 AM, Jan Hubicka wrote:
Hello,
diff --git a/gcc/hash-table.h b/gcc/hash-table.h
index 0f7e21a..443d16c 100644
--- a/gcc/hash-table.h
+++ b/gcc/hash-table.h
@@ -803,7 +803,10 @@ hash_table<Descriptor, Allocator>::empty_slow ()
m_size_prime_index = nindex;
}
else
- memset (entries, 0, size * sizeof (value_type));
+ {
+ for ( ; size; ++entries, --size)
+ *entries = value_type ();
+ }
m_n_deleted = 0;
m_n_elements = 0;
}
This change sends our periodic testers into an infinite loop. It is fault
of gcc 4.2 being used
as bootstrap compiler, but perhaps that can be worked around?
The warning in the original code could have been suppressed (by
casting the pointer to char*), but it was valid so I opted not
to. I'd expect it to be possible to work around the bug but
I don't have easy access to GCC 4.2 to reproduce it or verify
the fix.
FWIW, after looking at the function again, I wondered if zeroing
out the elements (either way) was the right thing to do and if
they shouldn't be cleared by calling Descriptor::mark_empty()
instead, like in alloc_entries(), but making that change broke
a bunch of ipa/ipa-pta-*.c tests. It's not really clear to me
what this code is supposed to do.
Martin
PS Does this help at all?
@@ -804,8 +804,8 @@ hash_table<Descriptor, Allocator>::empty_slow ()
}
else
{
- for ( ; size; ++entries, --size)
- *entries = value_type ();
+ for (size_t i = 0; i != size; ++i)
+ entries[i] = value_type ();
}
m_n_deleted = 0;
m_n_elements = 0;