From 0816bb32ac37b24d2f895f0c0464b7659fffd4fc Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Thu, 19 Jun 2025 17:49:33 +0100
Subject: [PATCH] [Matrix] Fix heap-use-after-free after 0fa373c77ded203eddb.

We need to skip instructions in FusedInsts, as they may have been
deleted. Fixes a heap-use-after-free after #141681.
---
 llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp b/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp
index fa9e44617b7c..ccb68700747b 100644
--- a/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp
+++ b/llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp
@@ -1140,6 +1140,9 @@ public:
     // Fourth, pre-process all the PHINode's. The incoming values will be
     // assigned later in VisitPHI.
     for (Instruction *Inst : MatrixInsts) {
+      if (FusedInsts.count(Inst))
+        continue;
+
       auto *PHI = dyn_cast<PHINode>(Inst);
       if (!PHI)
         continue;