Add a "seen blocks" cache to LVI to avoid a linear scan over the whole cache just to remove no blocks from the maps.
-15% on ARMDisassembler.cpp (Release build). It's not that great to add another
layer of caching to the caching-heavy LVI but I don't see a better way.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145770 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp
index 991fb82..02d9180 100644
--- a/lib/Analysis/LazyValueInfo.cpp
+++ b/lib/Analysis/LazyValueInfo.cpp
@@ -371,7 +371,11 @@
/// for cache updating.
typedef std::pair<AssertingVH<BasicBlock>, Value*> OverDefinedPairTy;
DenseSet<OverDefinedPairTy> OverDefinedCache;
-
+
+ /// SeenBlocks - Keep track of all blocks that we have ever seen, so we
+ /// don't spend time removing unused blocks from our caches.
+ DenseSet<AssertingVH<BasicBlock> > SeenBlocks;
+
/// BlockValueStack - This stack holds the state of the value solver
/// during a query. It basically emulates the callstack of the naive
/// recursive value lookup process.
@@ -470,6 +474,12 @@
}
void LazyValueInfoCache::eraseBlock(BasicBlock *BB) {
+ // Shortcut if we have never seen this block.
+ DenseSet<AssertingVH<BasicBlock> >::iterator I = SeenBlocks.find(BB);
+ if (I == SeenBlocks.end())
+ return;
+ SeenBlocks.erase(I);
+
SmallVector<OverDefinedPairTy, 4> ToErase;
for (DenseSet<OverDefinedPairTy>::iterator I = OverDefinedCache.begin(),
E = OverDefinedCache.end(); I != E; ++I) {
@@ -509,6 +519,7 @@
if (Constant *VC = dyn_cast<Constant>(Val))
return LVILatticeVal::get(VC);
+ SeenBlocks.insert(BB);
return lookup(Val)[BB];
}
@@ -517,6 +528,7 @@
return true;
ValueCacheEntryTy &Cache = lookup(Val);
+ SeenBlocks.insert(BB);
LVILatticeVal &BBLV = Cache[BB];
// OverDefinedCacheUpdater is a helper object that will update