From e8f8139429ffc41ae3a339d4a32e336a74f189c0 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Sat, 15 Jan 2011 10:16:23 +0000
Subject: [PATCH] Add a cache that protects mergefunc's internals from more
surprises in DenseSet.
Also, replace tabs with spaces. Yes, it's 2011.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123535 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Transforms/IPO/MergeFunctions.cpp | 32 ++++++++++++++++++++++-----
1 file changed, 27 insertions(+), 5 deletions(-)
diff --git a/lib/Transforms/IPO/MergeFunctions.cpp b/lib/Transforms/IPO/MergeFunctions.cpp
index c678db85900..49ebe65fe81 100644
--- a/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/lib/Transforms/IPO/MergeFunctions.cpp
@@ -109,10 +109,23 @@ public:
Func = NULL;
}
+ bool &getOrInsertCachedComparison(const ComparableFunction &Other,
+ bool &inserted) const {
+ typedef DenseMap<Function *, bool>::iterator iterator;
+ std::pair<iterator, bool> p =
+ CompareResultCache.insert(std::make_pair(Other.getFunc(), false));
+ inserted = p.second;
+ return p.first->second;
+ }
+
private:
explicit ComparableFunction(unsigned Hash)
: Func(NULL), Hash(Hash), TD(NULL) {}
+ // DenseMap::grow() triggers a recomparison of all keys in the map, which is
+ // wildly expensive. This cache tries to preserve known results.
+ mutable DenseMap<Function *, bool> CompareResultCache;
+
AssertingVH<Function> Func;
unsigned Hash;
TargetData *TD;
@@ -708,10 +721,10 @@ void MergeFunctions::RemoveUsers(Value *V) {
if (Instruction *I = dyn_cast<Instruction>(U.getUser())) {
Remove(I->getParent()->getParent());
} else if (isa<GlobalValue>(U.getUser())) {
- // do nothing
+ // do nothing
} else if (Constant *C = dyn_cast<Constant>(U.getUser())) {
- for (Value::use_iterator CUI = C->use_begin(), CUE = C->use_end();
- CUI != CUE; ++CUI)
+ for (Value::use_iterator CUI = C->use_begin(), CUE = C->use_end();
+ CUI != CUE; ++CUI)
Worklist.push_back(*CUI);
}
}
@@ -777,6 +790,15 @@ bool DenseMapInfo<ComparableFunction>::isEqual(const ComparableFunction &LHS,
return false;
assert(LHS.getTD() == RHS.getTD() &&
"Comparing functions for different targets");
- return FunctionComparator(LHS.getTD(),
- LHS.getFunc(), RHS.getFunc()).Compare();
+
+ bool inserted;
+ bool &result1 = LHS.getOrInsertCachedComparison(RHS, inserted);
+ if (!inserted)
+ return result1;
+ bool &result2 = RHS.getOrInsertCachedComparison(LHS, inserted);
+ if (!inserted)
+ return result1 = result2;
+
+ return result1 = result2 = FunctionComparator(LHS.getTD(), LHS.getFunc(),
+ RHS.getFunc()).Compare();
}