fix compile-time regression report by Joerg Sonnenberger:
cache result of Size/OffsetVisitor to speedup analysis of PHI nodes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172363 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index f88affb..1d27a83 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -387,17 +387,19 @@
V = V->stripPointerCasts();
if (isa<Instruction>(V) || isa<GEPOperator>(V)) {
- // If we have already seen this instruction, bail out.
- if (!SeenInsts.insert(V))
- return unknown();
+ // return cached value or insert unknown in cache if size of V was not
+ // computed yet in order to avoid recursions in PHis
+ std::pair<CacheMapTy::iterator, bool> CacheVal =
+ CacheMap.insert(std::make_pair(V, unknown()));
+ if (!CacheVal.second)
+ return CacheVal.first->second;
- SizeOffsetType Ret;
+ SizeOffsetType Result;
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
- Ret = visitGEPOperator(*GEP);
+ Result = visitGEPOperator(*GEP);
else
- Ret = visit(cast<Instruction>(*V));
- SeenInsts.erase(V);
- return Ret;
+ Result = visit(cast<Instruction>(*V));
+ return CacheMap[V] = Result;
}
if (Argument *A = dyn_cast<Argument>(V))