diff --git a/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp b/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
--- a/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
+++ b/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
@@ -182,16 +182,21 @@
 // Helper functions to build math functions approximations.
 //----------------------------------------------------------------------------//
 
-static Value min(ImplicitLocOpBuilder &builder, Value a, Value b) {
+// Return the minimum of the two values or NaN if value is NaN
+static Value min(ImplicitLocOpBuilder &builder, Value value, Value bound) {
   return builder.create<arith::SelectOp>(
-      builder.create<arith::CmpFOp>(arith::CmpFPredicate::OLT, a, b), a, b);
+      builder.create<arith::CmpFOp>(arith::CmpFPredicate::ULT, value, bound),
+      value, bound);
 }
 
-static Value max(ImplicitLocOpBuilder &builder, Value a, Value b) {
+// Return the maximum of the two values or NaN if value is NaN
+static Value max(ImplicitLocOpBuilder &builder, Value value, Value bound) {
   return builder.create<arith::SelectOp>(
-      builder.create<arith::CmpFOp>(arith::CmpFPredicate::OGT, a, b), a, b);
+      builder.create<arith::CmpFOp>(arith::CmpFPredicate::UGT, value, bound),
+      value, bound);
 }
 
+// Return the clamped value or NaN if value is NaN
 static Value clamp(ImplicitLocOpBuilder &builder, Value value, Value lowerBound,
                    Value upperBound) {
   return max(builder, min(builder, value, upperBound), lowerBound);