[mlir] std.call reference function return types in failure

[jpienaar]

Summary

Makes it easier to see type mismatch from failure locally.

[ftynse]

Can we have/update the test for this?

[jpienaar]

Adding test

[jpienaar]

Add new line at end

mlir/lib/Dialect/StandardOps/IR/Ops.cpp

if (getOperand(i).getType() != fnType.getInput(i))
       return emitOpError("operand type mismatch: expected operand type ")
              << fnType.getInput(i) << ", but provided "
              << getOperand(i).getType() << " for operand number " << i;
 
   if (fnType.getNumResults() != getNumResults())
     return emitOpError("incorrect number of results for callee");
 
   for (unsigned i = 0, e = fnType.getNumResults(); i != e; ++i)
-    if (getResult(i).getType() != fnType.getResult(i))
-      return emitOpError("result type mismatch");
+    if (getResult(i).getType() != fnType.getResult(i)) {
+      auto diag = emitOpError("result type mismatch at index ") << i;
+      diag.attachNote() << "      op result types: " << getResultTypes();
+      diag.attachNote() << "function result types: " << fnType.getResults();
+      return diag;
+    }
 
   return success();
 }
 
 FunctionType CallOp::getCalleeType() {
   return FunctionType::get(getContext(), getOperandTypes(), getResultTypes());
 }
 

mlir/test/Dialect/Standard/invalid.mlir

 
 // -----
 
 func @complex_constant_two_different_element_types() {
   // expected-error @+1 {{requires attribute's element types ('f32', 'f64') to match the element type of the op's return type ('f64')}}
   %0 = constant [1.0 : f32, -1.0 : f64] : complex<f64>
   return
 }
+
+// -----
+
+func @return_i32_f32() -> (i32, f32) {
+  %0 = constant 1 : i32
+  %1 = constant 1. : f32
+  return %0, %1 : i32, f32
+}
+
+func @call() {
+  // expected-error @+3 {{op result type mismatch at index 0}}
+  // expected-note @+2 {{op result types: 'f32', 'i32'}}
+  // expected-note @+1 {{function result types: 'i32', 'f32'}}
+  %0:2 = call @return_i32_f32() : () -> (f32, i32)
+  return
+}