[GVN/MemDep] Limit the size of the cache for non-local dependencies.

[alinas]

An attempt to resolve the issue flagged in PR150531

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

Author: Alina Sbirlea (alinas)

Changes

An attempt to resolve the issue flagged in PR150531

---

Full diff: https://github.com/llvm/llvm-project/pull/150539.diff

1 Files Affected:

• (modified) llvm/lib/Analysis/MemoryDependenceAnalysis.cpp (+9)

diff --git a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
index 3aa9909df8e55..20c38caaf37cd 100644
--- a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -80,6 +80,10 @@ static cl::opt<unsigned>
                      cl::desc("The number of blocks to scan during memory "
                               "dependency analysis (default = 200)"));
 
+static cl::opt<unsigned> CacheGlobalLimit(
+    "cache-global-limit", cl::Hidden, cl::init(5000),
+    cl::desc("The max number of entries allowed in a cache (default = 5000)"));
+
 // Limit on the number of memdep results to process.
 static const unsigned int NumResultsLimit = 100;
 
@@ -1138,6 +1142,11 @@ bool MemoryDependenceResults::getNonLocalPointerDepFromBB(
     return true;
   }
 
+  // If the size of this cache has surpassed the global limit, stop here.
+  if (Cache->size() > CacheGlobalLimit) {
+    return false;
+  }
+
   // Otherwise, either this is a new block, a block with an invalid cache
   // pointer or one that we're about to invalidate by putting more info into
   // it than its valid cache info.  If empty and not explicitly indicated as