[llvm] [HashRecognize] Fix compiler hang on dense use-def chain (PR #211711)

[Sean Clarke via llvm-commits]

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@@ -233,24 +233,37 @@ bool RecurrenceInfo::matchSimpleRecurrence(const PHINode *P) {
 BinaryOperator *
 RecurrenceInfo::digRecurrence(Instruction *V,
                               Instruction::BinaryOps BOWithConstOpToMatch) {
+  LLVM_DEBUG(dbgs() << DEBUG_TYPE " Digging for recurrence starting with %"
+                    << V->getName() << ":\n");
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xarkenz wrote:

Ah, ok. I wasn't entirely sure what the convention for debug statements was, I'll strip them.

https://github.com/llvm/llvm-project/pull/211711