[mlir][linalg] Fix crashes in parser on linalg ops without operands (#97944)

`parseDstStyleOp` parses both `ins()` and `outs()` optionally. The
parsers for `linalg.transpose`, `linalg.broadcast` and `linalg.map`
however assume that at least one operand is present in the state,
leading to crashes otherwise.

This patch adds checks to the parsers which stop them from crashing if
no operands were parsed. When the Ops are parsed successfuly, the
verifiers can work on them.

Fix #97857

Author: ubfx

mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp

@@ -1356,8 +1356,12 @@ ParseResult MapOp::parse(OpAsmParser &parser, OperationState &result) {
     return failure();
 
   if (payloadOpName.has_value()) {
-    addBodyWithPayloadOp(parser, result, payloadOpName.value(), payloadOpAttrs,
-                         ArrayRef(result.operands).drop_back());
+    if (!result.operands.empty())
+      addBodyWithPayloadOp(parser, result, payloadOpName.value(),
+                           payloadOpAttrs,
+                           ArrayRef(result.operands).drop_back());
+    else
+      result.addRegion();
   } else {
     SmallVector<OpAsmParser::Argument> regionArgs;
     if (parser.parseArgumentList(regionArgs, OpAsmParser::Delimiter::Paren,
@@ -1739,7 +1743,8 @@ static void buildIdentityRegion(OpBuilder &builder, Location loc,
                                 ValueRange outputs) {
   buildGenericRegion(builder, loc, region, inputs, outputs,
                      [](OpBuilder &b, Location loc, ValueRange args) {
-                       b.create<linalg::YieldOp>(loc, args[0]);
+                       if (!args.empty())
+                         b.create<linalg::YieldOp>(loc, args[0]);
                      });
 }
 

mlir/test/Dialect/Linalg/invalid.mlir

@@ -455,6 +455,32 @@ func.func @map_input_output_shape_mismatch(
 
 // -----
 
+func.func @map_no_operands1() {
+  // expected-error @+1 {{'linalg.map' op expected 1 or more operands, but found 0}}
+  linalg.map { arith.addf }
+}
+
+// -----
+
+func.func @map_no_operands2() {
+  // expected-error @+1 {{'linalg.map' op expected 1 or more operands, but found 0}}
+  "linalg.map"() ({
+    ^bb0:
+  }) : () -> ()
+}
+
+// -----
+
+func.func @map_no_operands3(
+    %lhs: tensor<64xf32>, %rhs: tensor<64xf32>, %init: tensor<64xf32>)
+    -> tensor<64xf32> {
+  // expected-error @+1 {{cannot name an operation with no results}}
+  %add = linalg.map { arith.addf }
+  func.return %add : tensor<64xf32>
+}
+
+// -----
+
 func.func @reduce_input_vs_init_dimension_mismatch(
     %input: tensor<16x32x64xf32>,
     %init: tensor<16x64xf32>)  -> tensor<16x64xf32> {
@@ -676,6 +702,30 @@ func.func @transpose_input_init_rank_mismatch(%input: tensor<16x32xf32>,
 
 // -----
 
+func.func @transpose_no_operands1() {
+  // expected-error @+1 {{'linalg.transpose' op expected 2 operands, but found 0}}
+  linalg.transpose permutation = [1, 0, 2]
+}
+
+// -----
+
+func.func @transpose_no_operands2() {
+  // expected-error @+1 {{'linalg.transpose' op expected 2 operands, but found 0}}
+  "linalg.transpose"() <{permutation = array<i64: 1, 0, 2>}> ({
+    ^bb0:
+  }) : () -> ()
+}
+
+// -----
+
+func.func @transpose_no_operands3() -> tensor<32x64x16xf32> {
+  // expected-error @+1 {{cannot name an operation with no results}}
+  %transpose = linalg.transpose permutation = [1, 0, 2]
+  func.return %transpose : tensor<32x64x16xf32>
+}
+
+// -----
+
 func.func @broadcast_input_dims_rank_mismatch(
     %input: tensor<4x16xf32>, %init: tensor<4x8x16xf32>)
     -> tensor<4x8x16xf32> {
@@ -728,6 +778,31 @@ func.func @broadcast_size_1_extension_not_supported(
 
 // -----
 
+func.func @broadcast_no_operands1() {
+  // expected-error @+1 {{'linalg.broadcast' op expected 2 operands, but found 0}}
+  linalg.broadcast dimensions = [1]
+}
+
+// -----
+
+func.func @broadcast_no_operands2() {
+  // expected-error @+1 {{'linalg.broadcast' op expected 2 operands, but found 0}}
+  "linalg.broadcast"() <{dimensions = array<i64: 1>}> ({
+    ^bb0:
+  }) : () -> ()
+}
+
+// -----
+
+func.func @broadcast_no_operands3()
+    -> tensor<4x?x16xf32> {
+  // expected-error @+1 {{cannot name an operation with no results}}
+  %broadcast = linalg.broadcast dimensions = [1]
+  func.return %broadcast : tensor<32x64x16xf32>
+}
+
+// -----
+
 func.func @missing_iterator_types() {
   // expected-error @below {{expected "iterator_types" array attribute}}
   linalg.generic {} ins() outs()