enable printing bf16 - TBD

Bf16 seems not well supported. On X86 is a promotion to f32.
See: https://reviews.llvm.org/rGfb34d531af953119593be74753b89baf99fbc194

Author: chelini

mlir/include/mlir/Dialect/LLVMIR/FunctionCallUtils.h

@@ -34,6 +34,7 @@ class LLVMFuncOp;
 /// of the libc).
 LLVM::LLVMFuncOp lookupOrCreatePrintI64Fn(ModuleOp moduleOp);
 LLVM::LLVMFuncOp lookupOrCreatePrintU64Fn(ModuleOp moduleOp);
+LLVM::LLVMFuncOp lookupOrCreatePrintBF16Fn(ModuleOp moduleOp);
 LLVM::LLVMFuncOp lookupOrCreatePrintF32Fn(ModuleOp moduleOp);
 LLVM::LLVMFuncOp lookupOrCreatePrintF64Fn(ModuleOp moduleOp);
 LLVM::LLVMFuncOp lookupOrCreatePrintOpenFn(ModuleOp moduleOp);

mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp

@@ -1082,7 +1082,10 @@ class VectorPrintOpConversion : public ConvertOpToLLVMPattern<vector::PrintOp> {
     VectorType vectorType = printType.dyn_cast<VectorType>();
     Type eltType = vectorType ? vectorType.getElementType() : printType;
     Operation *printer;
-    if (eltType.isF32()) {
+    if (eltType.isBF16()) {
+      printer =
+          LLVM::lookupOrCreatePrintBF16Fn(printOp->getParentOfType<ModuleOp>());
+    } else if (eltType.isF32()) {
       printer =
           LLVM::lookupOrCreatePrintF32Fn(printOp->getParentOfType<ModuleOp>());
     } else if (eltType.isF64()) {

mlir/lib/Dialect/LLVMIR/IR/FunctionCallUtils.cpp

@@ -26,6 +26,7 @@ using namespace mlir::LLVM;
 /// part of the libc).
 static constexpr llvm::StringRef kPrintI64 = "printI64";
 static constexpr llvm::StringRef kPrintU64 = "printU64";
+static constexpr llvm::StringRef kPrintBF16 = "printBF16";
 static constexpr llvm::StringRef kPrintF32 = "printF32";
 static constexpr llvm::StringRef kPrintF64 = "printF64";
 static constexpr llvm::StringRef kPrintOpen = "printOpen";
@@ -66,6 +67,12 @@ LLVM::LLVMFuncOp mlir::LLVM::lookupOrCreatePrintU64Fn(ModuleOp moduleOp) {
                           LLVM::LLVMVoidType::get(moduleOp->getContext()));
 }
 
+LLVM::LLVMFuncOp mlir::LLVM::lookupOrCreatePrintBF16Fn(ModuleOp moduleOp) {
+  return lookupOrCreateFn(moduleOp, kPrintBF16,
+                          FloatType::getBF16(moduleOp->getContext()),
+                          LLVM::LLVMVoidType::get(moduleOp->getContext()));
+}
+
 LLVM::LLVMFuncOp mlir::LLVM::lookupOrCreatePrintF32Fn(ModuleOp moduleOp) {
   return lookupOrCreateFn(moduleOp, kPrintF32,
                           Float32Type::get(moduleOp->getContext()),