[llvm] [TableGen] Add PrintError family overload that take a print function (PR #107333)

[Craig Topper via llvm-commits]

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@@ -1600,18 +1601,13 @@ static TreePatternNode &getOperandNum(unsigned OpNo, TreePatternNode &N,
     return N;
   }
 
-  OpNo -= NumResults;
-
-  if (OpNo >= N.getNumChildren()) {
-    std::string S;
-    raw_string_ostream OS(S);
-    OS << "Invalid operand number in type constraint " << (OpNo + NumResults)
-       << " ";
-    N.print(OS);
-    PrintFatalError(S);
+  if (OpNo - NumResults >= N.getNumChildren()) {
+    PrintFatalError([&N, OpNo](raw_ostream &OS) {
+      OS << formatv("Invalid operand number {0} in type constraint ", OpNo);
----------------
topperc wrote:

Doesn't formatv create a buffer to hold the full string before printing? Would `OS << "Invalid operand number " << OpNo << "in type constraint" be better?

https://github.com/llvm/llvm-project/pull/107333