[mlir][spirv] Handle vectors of integers of unsupported width (#118663)

Fixes: #118612

Author: kuhar

mlir/lib/Dialect/SPIRV/Transforms/SPIRVConversion.cpp

@@ -292,13 +292,19 @@ convertScalarType(const spirv::TargetEnv &targetEnv,
 }
 
 /// Converts a sub-byte integer `type` to i32 regardless of target environment.
+/// Returns a nullptr for unsupported integer types, including non sub-byte
+/// types.
 ///
 /// Note that we don't recognize sub-byte types in `spirv::ScalarType` and use
 /// the above given that these sub-byte types are not supported at all in
 /// SPIR-V; there are no compute/storage capability for them like other
 /// supported integer types.
 static Type convertSubByteIntegerType(const SPIRVConversionOptions &options,
                                       IntegerType type) {
+  if (type.getWidth() > 8) {
+    LLVM_DEBUG(llvm::dbgs() << "not a subbyte type\n");
+    return nullptr;
+  }
   if (options.subByteTypeStorage != SPIRVSubByteTypeStorage::Packed) {
     LLVM_DEBUG(llvm::dbgs() << "unsupported sub-byte storage kind\n");
     return nullptr;
@@ -348,6 +354,9 @@ convertVectorType(const spirv::TargetEnv &targetEnv,
     }
 
     Type elementType = convertSubByteIntegerType(options, intType);
+    if (!elementType)
+      return nullptr;
+
     if (type.getRank() <= 1 && type.getNumElements() == 1)
       return elementType;
 

mlir/test/Conversion/ArithToSPIRV/arith-to-spirv-unsupported.mlir

@@ -60,6 +60,14 @@ func.func @int_vector4_invalid(%arg0: vector<2xi16>) {
   return
 }
 
+// -----
+
+func.func @int_vector_invalid_bitwidth(%arg0: vector<2xi12>) {
+  // expected-error @+1 {{failed to legalize operation 'arith.addi'}}
+  %0 = arith.addi %arg0, %arg0: vector<2xi12>
+  return
+}
+
 ///===----------------------------------------------------------------------===//
 // Constant ops
 //===----------------------------------------------------------------------===//