From 82bcd985862892773fc9685aa6abcbb298267aa0 Mon Sep 17 00:00:00 2001
From: River Riddle <riddleriver@gmail.com>
Date: Tue, 27 Apr 2021 14:27:08 -0700
Subject: [PATCH] [mlir] Fix bug in ForwardDataFlowAnalysis solver

Explicitly check for uninitialized to prevent crashes in edge cases where the derived analysis creates a lattice element for a value that hasn't been visited yet.
---
 mlir/lib/Analysis/DataFlowAnalysis.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/lib/Analysis/DataFlowAnalysis.cpp b/mlir/lib/Analysis/DataFlowAnalysis.cpp
index ec1a13a..ef629c1 100644
--- a/mlir/lib/Analysis/DataFlowAnalysis.cpp
+++ b/mlir/lib/Analysis/DataFlowAnalysis.cpp
@@ -317,7 +317,7 @@ void ForwardDataFlowSolver::visitOperation(Operation *op) {
   for (Value operand : op->getOperands()) {
     AbstractLatticeElement *operandLattice =
         analysis.lookupLatticeElement(operand);
-    if (!operandLattice)
+    if (!operandLattice || operandLattice->isUninitialized())
       return;
     operandLattices.push_back(operandLattice);
   }
-- 
2.7.4