Convert TableGen assert to error

[stephenneuendorffer]

Summary

This gives a nice message about the location of errors in a large
tablegen file, which is much more useful for users

[stephenneuendorffer]

Ping... in general is there an issue converting asserts() to proper error messages in tablegen?

[craig.topper]

Seems fine, but is there a way to write this in tablegen that would trigger the assert?

[stephenneuendorffer]

In D102740#2791585, @craig.topper wrote:

Seems fine, but is there a way to write this in tablegen that would trigger the assert?

Yes, I hit it with an out of tree backend, but I don't have an easy way to recreate it. Are you concerned about a test?

[craig.topper]

In D102740#2791964, @stephenneuendorffer wrote:

In D102740#2791585, @craig.topper wrote:

Seems fine, but is there a way to write this in tablegen that would trigger the assert?

Yes, I hit it with an out of tree backend, but I don't have an easy way to recreate it. Are you concerned about a test?

I'm not all that concerned about a test just trying to get my head around this. I just realized this is counting the number of results from the thing that is being cast which makes a lot more sense. I thought it was trying to count the number of results for the ValueType itself and I couldn't figure out how to write that.

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

2857

case -> cast ?

[stephenneuendorffer]

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

2857

ooo yeah, I'll fix that.

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

if (Operator->isSubClassOf("ValueType")) {
     // node.
     if (Dag->getNumArgs() != 1)
       error("Type cast only takes one operand!");
 
     TreePatternNodePtr New =
         ParseTreePattern(Dag->getArg(0), Dag->getArgNameStr(0));
 
     // Apply the type cast.
-    assert(New->getNumTypes() == 1 && "FIXME: Unhandled");
+    if (New->getNumTypes() != 1)
+      error("Type cast can only have one type!");
     const CodeGenHwModes &CGH = getDAGPatterns().getTargetInfo().getHwModes();
     New->UpdateNodeType(0, getValueTypeByHwMode(Operator, CGH), *this);
 
     if (!OpName.empty())
       error("ValueType cast should not have a name!");
     return New;
   }