Improve caching scheme in ProvenanceAnalysis.

Summary:
ProvenanceAnalysis::related(A, B) currently memoizes its results, and on big
tests the cache grows too large, and we're spending most of the time
growing/looking through DenseMap.

This patch reduces the size of the cache by normalizing keys first: we do that
by calling GetUnderlyingObjCPtr on the input values. The results of
GetUnderlyingObjCPtr are also memoized in a separate cache.

The patch doesn't bring noticable changes to compile time on CTMark, however
significantly helps one of our internal tests.

Reviewers: gottesmm

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D44270

llvm-svn: 327328

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/ObjCARC/ProvenanceAnalysis.h b/llvm/lib/Transforms/ObjCARC/ProvenanceAnalysis.h
index 5e676167a6a..f21ea3666b1 100644
--- a/llvm/lib/Transforms/ObjCARC/ProvenanceAnalysis.h
+++ b/llvm/lib/Transforms/ObjCARC/ProvenanceAnalysis.h
@@ -56,6 +56,8 @@ class ProvenanceAnalysis {
 
   CachedResultsTy CachedResults;
 
+  DenseMap<const Value *, const Value *> UnderlyingObjCPtrCache;
+
   bool relatedCheck(const Value *A, const Value *B, const DataLayout &DL);
   bool relatedSelect(const SelectInst *A, const Value *B);
   bool relatedPHI(const PHINode *A, const Value *B);
@@ -73,6 +75,7 @@ public:
 
   void clear() {
     CachedResults.clear();
+    UnderlyingObjCPtrCache.clear();
   }
 };