[Mlir-commits] [mlir] [mlir][inliner] Return early if the inliningThreshold is 0U or -1U. (PR #86287)

[Fabian Tschopp]

https://github.com/naibaf7 updated https://github.com/llvm/llvm-project/pull/86287

>From 9df57cb2dd39be8c6bde24866625740812cb8fec Mon Sep 17 00:00:00 2001
From: Fabian Tschopp <fabian.tschopp at modular.com>
Date: Fri, 22 Mar 2024 15:15:47 +0100
Subject: [PATCH] [mlir][inliner] Return early if the inliningThreshold is 0U
 or -1U.

Computing the inlinling profitability can be costly due to walking the
graph when counting the number of operations.

This PR addresses that by returning early if the threshold is set to
never or always inline.
---
 mlir/lib/Transforms/InlinerPass.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/mlir/lib/Transforms/InlinerPass.cpp b/mlir/lib/Transforms/InlinerPass.cpp
index 08d8dbf73a6a1d..428bb6aa5cc511 100644
--- a/mlir/lib/Transforms/InlinerPass.cpp
+++ b/mlir/lib/Transforms/InlinerPass.cpp
@@ -93,12 +93,19 @@ InlinerPass::InlinerPass(std::function<void(OpPassManager &)> defaultPipeline,
 // Return true if the inlining ratio does not exceed the threshold.
 static bool isProfitableToInline(const Inliner::ResolvedCall &resolvedCall,
                                  unsigned inliningThreshold) {
+  // ratio <= 0U will always be false. 
+  if (inliningThreshold == 0U)
+    return false;
+  // ratio <= -1U will always be true.
+  if (inliningThreshold == -1U)
+    return true;
+
   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)
+  if (!callerRegion || !calleeRegion)
     return true;
 
   auto countOps = [](Region *region) {