| Message ID | CAFiYyc1qMQd4PPU+-v+XMpH9iDOF_oJj=bX6Ln3+SaOkjhYVsA@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On 06/30/2017 02:34 AM, Richard Biener wrote: > On Thu, Jun 29, 2017 at 10:23 PM, Martin Sebor <msebor@gmail.com> wrote: >> 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; > > alloc_entries uses mark_empty. untested: Right. That was my initial thought as well but it broke a number of ipa/ipa-pta-*.c tests. I didn't have time to investigate why. Martin > > Index: gcc/hash-table.h > =================================================================== > --- gcc/hash-table.h (revision 249780) > +++ gcc/hash-table.h (working copy) > @@ -804,8 +804,8 @@ hash_table<Descriptor, Allocator>::empty > } > else > { > - for ( ; size; ++entries, --size) > - *entries = value_type (); > + for (size_t i = 0; i < size; ++i) > + mark_empty (entries[i]); > } > m_n_deleted = 0; > m_n_elements = 0; >
Index: gcc/hash-table.h =================================================================== --- gcc/hash-table.h (revision 249780) +++ gcc/hash-table.h (working copy) @@ -804,8 +804,8 @@ hash_table<Descriptor, Allocator>::empty } else { - for ( ; size; ++entries, --size) - *entries = value_type (); + for (size_t i = 0; i < size; ++i) + mark_empty (entries[i]); } m_n_deleted = 0; m_n_elements = 0;