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
@@ -1075,6 +1075,28 @@
   return success();
 }
 
+//----------------------------------------------------------------------------//
+// Tan decomposition to sin / cos.
+//----------------------------------------------------------------------------//
+
+namespace {
+struct TanDecomposition : public OpRewritePattern<math::TanOp> {
+  using OpRewritePattern::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(math::TanOp op,
+                                PatternRewriter &rewriter) const final {
+    ImplicitLocOpBuilder b(op->getLoc(), rewriter);
+    Value operand = op.getOperand();
+    Type type = operand.getType();
+    Value sin = b.create<math::SinOp>(type, operand);
+    Value cos = b.create<math::CosOp>(type, operand);
+    Value div = b.create<arith::DivFOp>(type, sin, cos);
+    rewriter.replaceOp(op, div);
+    return success();
+  }
+};
+} // namespace
+
 //----------------------------------------------------------------------------//
 // Sin and Cos approximation.
 //----------------------------------------------------------------------------//
@@ -1291,7 +1313,7 @@
   patterns.add<AtanApproximation, Atan2Approximation, TanhApproximation,
                LogApproximation, Log2Approximation, Log1pApproximation,
                ErfPolynomialApproximation, ExpApproximation, ExpM1Approximation,
-               ReuseF32Expansion<math::Atan2Op>,
+               ReuseF32Expansion<math::Atan2Op>, TanDecomposition,
                SinAndCosApproximation<true, math::SinOp>,
                SinAndCosApproximation<false, math::CosOp>>(
       patterns.getContext());
diff --git a/mlir/test/Dialect/Math/polynomial-approximation.mlir b/mlir/test/Dialect/Math/polynomial-approximation.mlir
--- a/mlir/test/Dialect/Math/polynomial-approximation.mlir
+++ b/mlir/test/Dialect/Math/polynomial-approximation.mlir
@@ -593,3 +593,10 @@
   %0 = math.atan2 %arg0, %arg1 : f16
   return %0 : f16
 }
+
+// CHECK-LABEL: @tan_scalar
+func.func @tan_scalar(%arg0 : f32) -> f32 {
+  // CHECK-NOT: math.tan
+  %0 = math.tan %arg0 : f32
+  return %0 : f32
+}