[llvm] [ObjectSizeOffsetVisitor] Add a max recursion depth (PR #67479)

[Arthur Eubanks via llvm-commits]

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@@ -50,6 +51,12 @@ using namespace llvm;
 
 #define DEBUG_TYPE "memory-builtins"
 
+static cl::opt<unsigned> ObjectSizeOffsetVisitorMaxRecurseDepth(
+    "object-size-offset-visitor-max-recurse-depth",
+    cl::desc(
+        "Maximum number of PHIs for ObjectSizeOffsetVisitor to look through"),
+    cl::init(100));
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aeubanks wrote:

Lowered to 20.
I think it's unlikely that we hit huge fanout in real world code, it's typically pretty linear at least with large autogenerated code. In the case I was looking at, this dropped DSE time from >30s to <1s.

https://github.com/llvm/llvm-project/pull/67479