[mlir] Add operator<< for printing Block (#92550)

Turns out it was already in Analysis/CFGLoopInfo, so just move it
to IR/AsmPrinter.

Author: kparzysz

mlir/include/mlir/Analysis/CFGLoopInfo.h

@@ -49,8 +49,6 @@ class CFGLoopInfo : public llvm::LoopInfoBase<mlir::Block, mlir::CFGLoop> {
   CFGLoopInfo(const llvm::DominatorTreeBase<mlir::Block, false> &domTree);
 };
 
-raw_ostream &operator<<(raw_ostream &os, mlir::Block &block);
-
 } // namespace mlir
 
 #endif // MLIR_ANALYSIS_LOOPINFO_H

mlir/include/mlir/IR/Block.h

@@ -18,6 +18,7 @@
 
 namespace llvm {
 class BitVector;
+class raw_ostream;
 } // namespace llvm
 
 namespace mlir {
@@ -401,6 +402,8 @@ class Block : public IRObjectWithUseList<BlockOperand>,
 
   friend struct llvm::ilist_traits<Block>;
 };
+
+raw_ostream &operator<<(raw_ostream &, Block &);
 } // namespace mlir
 
 #endif // MLIR_IR_BLOCK_H

mlir/lib/Analysis/CFGLoopInfo.cpp

@@ -23,8 +23,3 @@ CFGLoopInfo::CFGLoopInfo(
     const llvm::DominatorTreeBase<mlir::Block, false> &domTree) {
   analyze(domTree);
 }
-
-raw_ostream &mlir::operator<<(raw_ostream &os, mlir::Block &block) {
-  block.print(os);
-  return os;
-}

mlir/lib/IR/AsmPrinter.cpp

@@ -3984,6 +3984,11 @@ void Block::printAsOperand(raw_ostream &os, AsmState &state) {
   printer.printBlockName(this);
 }
 
+raw_ostream &mlir::operator<<(raw_ostream &os, Block &block) {
+  block.print(os);
+  return os;
+}
+
 //===--------------------------------------------------------------------===//
 // Custom printers
 //===--------------------------------------------------------------------===//