Index: llvm/include/llvm/ADT/FloatingPointMode.h
===================================================================
--- llvm/include/llvm/ADT/FloatingPointMode.h
+++ llvm/include/llvm/ADT/FloatingPointMode.h
@@ -288,6 +288,9 @@
   return NewMask;
 }
 
+/// Write a human readable form of \p Mask to \p OS
+raw_ostream &operator<<(raw_ostream &OS, FPClassTest Mask);
+
 } // namespace llvm
 
 #endif // LLVM_ADT_FLOATINGPOINTMODE_H
Index: llvm/lib/IR/Attributes.cpp
===================================================================
--- llvm/lib/IR/Attributes.cpp
+++ llvm/lib/IR/Attributes.cpp
@@ -421,56 +421,6 @@
   llvm_unreachable("Invalid ModRefInfo");
 }
 
-// Every bitfield has a unique name and one or more aliasing names that cover
-// multiple bits. Names should be listed in order of preference, with higher
-// popcounts listed first.
-//
-// Bits are consumed as printed. Each field should only be represented in one
-// printed field.
-static constexpr std::pair<unsigned, StringLiteral> NoFPClassName[] = {
-  {fcAllFlags, "all"},
-  {fcNan, "nan"},
-  {fcSNan, "snan"},
-  {fcQNan, "qnan"},
-  {fcInf, "inf"},
-  {fcNegInf, "ninf"},
-  {fcPosInf, "pinf"},
-  {fcZero, "zero"},
-  {fcNegZero, "nzero"},
-  {fcPosZero, "pzero"},
-  {fcSubnormal, "sub"},
-  {fcNegSubnormal, "nsub"},
-  {fcPosSubnormal, "psub"},
-  {fcNormal, "norm"},
-  {fcNegNormal, "nnorm"},
-  {fcPosNormal, "pnorm"}
-};
-
-static std::string getNoFPClassAttrAsString(unsigned Mask) {
-  std::string Result("nofpclass(");
-  raw_string_ostream OS(Result);
-
-  if (Mask == 0) {
-    OS << "none)";
-    return Result;
-  }
-
-  ListSeparator LS(" ");
-  for (auto [BitTest, Name] : NoFPClassName) {
-    if ((Mask & BitTest) == BitTest) {
-      OS << LS << Name;
-
-      // Clear the bits so we don't print any aliased names later.
-      Mask &= ~BitTest;
-    }
-  }
-
-  assert(Mask == 0 && "didn't print some mask bits");
-
-  OS << ')';
-  return Result;
-}
-
 std::string Attribute::getAsString(bool InAttrGrp) const {
   if (!pImpl) return {};
 
@@ -604,8 +554,12 @@
     return Result;
   }
 
-  if (hasAttribute(Attribute::NoFPClass))
-    return getNoFPClassAttrAsString(getValueAsInt());
+  if (hasAttribute(Attribute::NoFPClass)) {
+    std::string Result = "nofpclass";
+    raw_string_ostream OS(Result);
+    OS << getNoFPClass();
+    return Result;
+  }
 
   // Convert target-dependent attributes to strings of the form:
   //
Index: llvm/lib/Support/CMakeLists.txt
===================================================================
--- llvm/lib/Support/CMakeLists.txt
+++ llvm/lib/Support/CMakeLists.txt
@@ -165,6 +165,7 @@
   FileCollector.cpp
   FileUtilities.cpp
   FileOutputBuffer.cpp
+  FloatingPointMode.cpp
   FoldingSet.cpp
   FormattedStream.cpp
   FormatVariadic.cpp
Index: llvm/lib/Support/FloatingPointMode.cpp
===================================================================
--- /dev/null
+++ llvm/lib/Support/FloatingPointMode.cpp
@@ -0,0 +1,61 @@
+//===- FloatingPointMode.cpp ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/FloatingPointMode.h"
+#include "llvm/ADT/StringExtras.h"
+
+using namespace llvm;
+
+// Every bitfield has a unique name and one or more aliasing names that cover
+// multiple bits. Names should be listed in order of preference, with higher
+// popcounts listed first.
+//
+// Bits are consumed as printed. Each field should only be represented in one
+// printed field.
+static constexpr std::pair<FPClassTest, StringLiteral> NoFPClassName[] = {
+  {fcAllFlags, "all"},
+  {fcNan, "nan"},
+  {fcSNan, "snan"},
+  {fcQNan, "qnan"},
+  {fcInf, "inf"},
+  {fcNegInf, "ninf"},
+  {fcPosInf, "pinf"},
+  {fcZero, "zero"},
+  {fcNegZero, "nzero"},
+  {fcPosZero, "pzero"},
+  {fcSubnormal, "sub"},
+  {fcNegSubnormal, "nsub"},
+  {fcPosSubnormal, "psub"},
+  {fcNormal, "norm"},
+  {fcNegNormal, "nnorm"},
+  {fcPosNormal, "pnorm"}
+};
+
+raw_ostream &operator<<(raw_ostream &OS, FPClassTest Mask) {
+  OS << '(';
+
+  if (Mask == fcNone) {
+    OS << "none)";
+    return OS;
+  }
+
+  ListSeparator LS(" ");
+  for (auto [BitTest, Name] : NoFPClassName) {
+    if ((Mask & BitTest) == BitTest) {
+      OS << LS << Name;
+
+      // Clear the bits so we don't print any aliased names later.
+      Mask &= ~BitTest;
+    }
+  }
+
+  assert(Mask == 0 && "didn't print some mask bits");
+
+  OS << ')';
+  return OS;
+}