From 5f34259609f604bfcd5cbf324a32d265e6a5d347 Mon Sep 17 00:00:00 2001
From: Alex Zinenko <zinenko@google.com>
Date: Mon, 27 Mar 2023 14:53:11 +0000
Subject: [PATCH] [mlir] FuncToLLVM: fail gracefully in bare pointer
 multi-result covnersion

When type conversion fails, return pattern failure instead of crashing.

Closes #61717.
---
 mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp           | 3 +++
 mlir/test/Conversion/FuncToLLVM/func-memref-return.mlir | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp b/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp
index bbfb628..7200b2b 100644
--- a/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp
+++ b/mlir/lib/Conversion/FuncToLLVM/FuncToLLVM.cpp
@@ -675,6 +675,9 @@ struct ReturnOpLowering : public ConvertOpToLLVMPattern<func::ReturnOp> {
     // returning.
     auto packedType =
         getTypeConverter()->packFunctionResults(op.getOperandTypes());
+    if (!packedType) {
+      return rewriter.notifyMatchFailure(op, "could not convert result types");
+    }
 
     Value packed = rewriter.create<LLVM::UndefOp>(loc, packedType);
     for (auto [idx, operand] : llvm::enumerate(updatedOperands)) {
diff --git a/mlir/test/Conversion/FuncToLLVM/func-memref-return.mlir b/mlir/test/Conversion/FuncToLLVM/func-memref-return.mlir
index e8f73a3..8663ce8 100644
--- a/mlir/test/Conversion/FuncToLLVM/func-memref-return.mlir
+++ b/mlir/test/Conversion/FuncToLLVM/func-memref-return.mlir
@@ -95,3 +95,11 @@ func.func @check_return(%in : memref<?xi8>) -> memref<?xi8> {
   // BAREPTR: llvm.return {{.*}} : !llvm.struct<(ptr, ptr, i64, array<1 x i64>, array<1 x i64>)>
   return %in : memref<?xi8>
 }
+
+// -----
+
+// BAREPTR-LABEL: func @unconvertible_multiresult
+// BAREPTR-SAME: %{{.*}}: memref<?xf32>, %{{.*}}: memref<?xf32>) -> (memref<?xf32>, memref<?xf32>)
+func.func @unconvertible_multiresult(%arg0: memref<?xf32> , %arg1: memref<?xf32>) -> (memref<?xf32>, memref<?xf32>) {
+  return %arg0, %arg1 : memref<?xf32>, memref<?xf32>
+}
-- 
2.7.4