When the hash function uses object pointers all free entries eventually
become tombstones as they are used at least once, regardless of the size.
DenseMap cannot function with zero empty keys, so it double size to get
get ridof the tombstones.
However DenseMap never shrinks automatically unless it is cleared, so
the net result is that certain tables grow infinitely.
The solution is to make a fresh copy of the table without tombstones
instead of doubling size, by simply calling grow with the current size.
Patch by José Fonseca!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128564 91177308-0d34-0410-b5e6-96231b3b80d8
This makes lookup slightly more expensive but it's worth it, unused
DenseMaps are common in LLVM code apparently.
1% speedup on clang -O3 bzip2.c
4% speedup on clang -O3 oggenc.c (Release build of clang on i386/linux)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127088 91177308-0d34-0410-b5e6-96231b3b80d8
isPodLike type trait. This is a generally useful type trait for
more than just DenseMap, and we really care about whether something
acts like a pod, not whether it really is a pod.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91421 91177308-0d34-0410-b5e6-96231b3b80d8
This patch forbids implicit conversion of DenseMap::const_iterator to
DenseMap::iterator which was possible because DenseMapIterator inherited
(publicly) from DenseMapConstIterator. Conversion the other way around is now
allowed as one may expect.
The template DenseMapConstIterator is removed and the template parameter
IsConst which specifies whether the iterator is constant is added to
DenseMapIterator.
Actually IsConst parameter is not necessary since the constness can be
determined from KeyT but this is not relevant to the fix and can be addressed
later.
Patch by Victor Zverovich!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86636 91177308-0d34-0410-b5e6-96231b3b80d8
intuitive.
It does NOT update the value if the key is already in the map,
it also returns false if the key is already in the map, regardless
if the value matched.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83458 91177308-0d34-0410-b5e6-96231b3b80d8
/// lookup - Return the entry for the specified key, or a default
/// constructed value if no such entry exists.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55523 91177308-0d34-0410-b5e6-96231b3b80d8
Added method FindAndConstruct() to DenseMap, which does the same thing as
operator[], except that it refers value_type& (a reference to both the
key and mapped data pair). This method is useful for clients that wish
to access the stored key value, as opposed to the key used to do the
actual lookup (these need not always be the same).
Redefined operator[] to use FindAndConstruct() (same logic).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43594 91177308-0d34-0410-b5e6-96231b3b80d8
and time usage.
Fixup operator == to make this work, and add a resize method to DenseMap
so we can resize our hashtable once we know how big it should be.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42269 91177308-0d34-0410-b5e6-96231b3b80d8
Add a new DenseMapInfo::isEqual method to allow clients to redefine
the equality predicate used when probing the hash table.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42042 91177308-0d34-0410-b5e6-96231b3b80d8
