[Mlir-commits] [mlir] [RFC][mlir] Add profitability callback to the Inliner. (PR #84258)

[Mehdi Amini]

================
@@ -88,6 +90,35 @@ InlinerPass::InlinerPass(std::function<void(OpPassManager &)> defaultPipeline,
   config.setOpPipelines(std::move(opPipelines));
 }
 
+// Return true if the inlining ratio does not exceed the threshold.
+static bool isProfitableToInline(const Inliner::ResolvedCall &resolvedCall,
+                                 unsigned inliningThreshold) {
+  Region *callerRegion = resolvedCall.sourceNode->getCallableRegion();
+  Region *calleeRegion = resolvedCall.targetNode->getCallableRegion();
+
+  // We should not get external nodes here, but just return true
+  // for now to preserve the original behavior of the inliner pass.
+  if (!calleeRegion || !calleeRegion)
+    return true;
+
+  auto countOps = [](Region *region) {
+    unsigned count = 0;
+    region->walk([&](Operation *) { ++count; });
+    return count;
+  };
+
+  unsigned callerOps = countOps(callerRegion);
+
+  // Always inline empty callees (if it is possible at all).
+  if (callerOps == 0)
+    return true;
+
+  unsigned ratio = countOps(calleeRegion) * 100 / callerOps;
+  LLVM_DEBUG(llvm::dbgs() << "Callee / caller operation ratio (max: "
+                          << inliningThreshold << "): " << ratio << "\n");
----------------
joker-eph wrote:

```suggestion
                          << inliningThreshold << "%): " << ratio << "%\n");
```

https://github.com/llvm/llvm-project/pull/84258