diff --git a/mlir/include/mlir/Dialect/Arith/IR/ArithOps.td b/mlir/include/mlir/Dialect/Arith/IR/ArithOps.td
--- a/mlir/include/mlir/Dialect/Arith/IR/ArithOps.td
+++ b/mlir/include/mlir/Dialect/Arith/IR/ArithOps.td
@@ -71,7 +71,7 @@
     Arguments<(ins FloatLike:$operand,
       DefaultValuedAttr<Arith_FastMathAttr, "FastMathFlags::none">:$fastmath)>,
     Results<(outs FloatLike:$result)> {
-  let assemblyFormat = [{ $operand custom<ArithFastMathAttr>($fastmath)
+  let assemblyFormat = [{ $operand (`fastmath` `` $fastmath^)?
                           attr-dict `:` type($result) }];
 }
 
@@ -83,7 +83,7 @@
     Arguments<(ins FloatLike:$lhs, FloatLike:$rhs,
       DefaultValuedAttr<Arith_FastMathAttr, "FastMathFlags::none">:$fastmath)>,
     Results<(outs FloatLike:$result)> {
-  let assemblyFormat = [{ $lhs `,` $rhs `` custom<ArithFastMathAttr>($fastmath)
+  let assemblyFormat = [{ $lhs `,` $rhs (`fastmath` `` $fastmath^)?
                           attr-dict `:` type($result) }];
 }
 
diff --git a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
--- a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
+++ b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
@@ -23,31 +23,6 @@
 using namespace mlir;
 using namespace mlir::arith;
 
-//===----------------------------------------------------------------------===//
-// Floating point op parse/print helpers
-//===----------------------------------------------------------------------===//
-static ParseResult parseArithFastMathAttr(OpAsmParser &parser,
-                                          Attribute &attr) {
-  if (succeeded(
-          parser.parseOptionalKeyword(FastMathFlagsAttr::getMnemonic()))) {
-    attr = FastMathFlagsAttr::parse(parser, Type{});
-    return success(static_cast<bool>(attr));
-  } else {
-    // No fastmath attribute mnemonic present - defer attribute creation and use
-    // the default value.
-    return success();
-  }
-}
-
-static void printArithFastMathAttr(OpAsmPrinter &printer, Operation *op,
-                                   FastMathFlagsAttr fmAttr) {
-  // Elide printing the fastmath attribute when fastmath=none
-  if (fmAttr && (fmAttr.getValue() != FastMathFlags::none)) {
-    printer << " " << FastMathFlagsAttr::getMnemonic();
-    fmAttr.print(printer);
-  }
-}
-
 //===----------------------------------------------------------------------===//
 // Pattern helpers
 //===----------------------------------------------------------------------===//