RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-02-01 05:01:59 +01:00
Code Issues Projects Releases Wiki Activity

[ADT] Add a much simpler loop to DenseMap::clear when the types are

Browse Source 
POD-like and we can just splat the empty key across memory.

Sadly we can't optimize the normal loop well enough because we can't
turn the conditional store into an unconditional store according to the
memory model.

This loop actually showed up in a profile of code that was calling clear
as a serious source of time. =[

llvm-svn: 310189
This commit is contained in:
Chandler Carruth 2017-08-05 22:48:37 +00:00
parent 4a79563b18
commit 49c5e16507
1 changed files with 14 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
include/llvm/ADT/DenseMap.h
View File

@ -107,17 +107,23 @@ public:
}
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
unsigned NumEntries = getNumEntries();
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
P->getSecond().~ValueT();
--NumEntries;
}
if (isPodLike<KeyT>::value && isPodLike<ValueT>::value) {
// Use a simpler loop when these are trivial types.
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P)
P->getFirst() = EmptyKey;
} else {
unsigned NumEntries = getNumEntries();
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
P->getSecond().~ValueT();
--NumEntries;
}
P->getFirst() = EmptyKey;
}
}
assert(NumEntries == 0 && "Node count imbalance!");
}
assert(NumEntries == 0 && "Node count imbalance!");
setNumEntries(0);
setNumTombstones(0);
}