[Mlir-commits] [mlir] [mlir][SCFToEmitC] Don't convert unsupported types in EmitC (PR #131786)

[Longsheng Mou]

https://github.com/CoTinker created https://github.com/llvm/llvm-project/pull/131786

This PR adds check for unsupported types in emitc, which fixes a crash. Fixes #131442.

>From c2bff67af9c1e70a2b24f96b555e9cb8d647d3e0 Mon Sep 17 00:00:00 2001
From: Longsheng Mou <longshengmou at gmail.com>
Date: Tue, 18 Mar 2025 19:22:11 +0800
Subject: [PATCH 1/2] [mlir][emitc] Don't convert unsupported types in EmitC

This PR adds check for unsupported types in emitc, which fixes a
crash.
---
 mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
index 92523ca4f12b2..6f57703bf17b3 100644
--- a/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
+++ b/mlir/lib/Conversion/SCFToEmitC/SCFToEmitC.cpp
@@ -322,7 +322,11 @@ void SCFToEmitCPass::runOnOperation() {
   // Fallback converter
   // See note https://mlir.llvm.org/docs/DialectConversion/#type-converter
   // Type converters are called most to least recently inserted
-  typeConverter.addConversion([](Type t) { return t; });
+  typeConverter.addConversion([](Type type) -> std::optional<Type> {
+    if (emitc::isSupportedEmitCType(type))
+      return type;
+    return {};
+  });
   populateEmitCSizeTTypeConversions(typeConverter);
   populateSCFToEmitCConversionPatterns(patterns, typeConverter);
 

>From 1dfdb33ccecd5c606b91443d6a6be7542356dcbe Mon Sep 17 00:00:00 2001
From: Longsheng Mou <longshengmou at gmail.com>
Date: Tue, 18 Mar 2025 19:24:54 +0800
Subject: [PATCH 2/2] add test

---
 .../Conversion/SCFToEmitC/scf-to-emitc-failed.mlir     | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 mlir/test/Conversion/SCFToEmitC/scf-to-emitc-failed.mlir

diff --git a/mlir/test/Conversion/SCFToEmitC/scf-to-emitc-failed.mlir b/mlir/test/Conversion/SCFToEmitC/scf-to-emitc-failed.mlir
new file mode 100644
index 0000000000000..02c27deaa7a13
--- /dev/null
+++ b/mlir/test/Conversion/SCFToEmitC/scf-to-emitc-failed.mlir
@@ -0,0 +1,10 @@
+// RUN: mlir-opt -convert-scf-to-emitc %s -split-input-file -verify-diagnostics
+
+func.func @unsupported_type_vector(%arg0 : index, %arg1 : index, %arg2 : index) -> vector<3xindex> {
+  %zero = arith.constant dense<0> : vector<3xindex>
+  // expected-error at +1 {{failed to legalize operation 'scf.for'}}
+  %r = scf.for %i0 = %arg0 to %arg1 step %arg2 iter_args(%acc = %zero) -> vector<3xindex> {
+    scf.yield %acc : vector<3xindex>
+  }
+  return %r : vector<3xindex>
+}