diff --git a/mlir/lib/Dialect/Math/Transforms/ExpandPatterns.cpp b/mlir/lib/Dialect/Math/Transforms/ExpandPatterns.cpp
index 1750171b81a10..fceafcff8490c 100644
--- a/mlir/lib/Dialect/Math/Transforms/ExpandPatterns.cpp
+++ b/mlir/lib/Dialect/Math/Transforms/ExpandPatterns.cpp
@@ -108,7 +108,7 @@ static LogicalResult convertTanhOp(math::TanhOp op, PatternRewriter &rewriter) {
   // Compute sign(x) = cast<float_type>(x < 0) * (-2) + 1
   Value sign = rewriter.create<arith::CmpFOp>(loc, arith::CmpFPredicate::OLT,
                                               op.getOperand(), zero);
-  sign = rewriter.create<arith::SIToFPOp>(loc, floatType, sign);
+  sign = rewriter.create<arith::UIToFPOp>(loc, floatType, sign);
   sign = rewriter.create<arith::MulFOp>(loc, sign, negTwo);
   sign = rewriter.create<arith::AddFOp>(loc, sign, one);
 
diff --git a/mlir/test/Dialect/Math/expand-math.mlir b/mlir/test/Dialect/Math/expand-math.mlir
index 86ee5c8620472..6326d3a71874b 100644
--- a/mlir/test/Dialect/Math/expand-math.mlir
+++ b/mlir/test/Dialect/Math/expand-math.mlir
@@ -9,7 +9,7 @@ func.func @tanh(%arg: f32) -> f32 {
 // CHECK-DAG: %[[ONE:.+]] = arith.constant 1.000000e+00 : f32
 // CHECK-DAG: %[[TWO:.+]] = arith.constant -2.000000e+00 : f32
 // CHECK: %[[VAL0:.+]] = arith.cmpf olt, %arg0, %[[ZERO]] : f32
-// CHECK: %[[VAL1:.+]] = arith.sitofp %[[VAL0]] : i1 to f32
+// CHECK: %[[VAL1:.+]] = arith.uitofp %[[VAL0]] : i1 to f32
 // CHECK: %[[VAL2:.+]] = arith.mulf %[[VAL1]], %[[TWO]] : f32
 // CHECK: %[[SIGN:.+]] = arith.addf %[[VAL2]], %[[ONE]] : f32
 // CHECK: %[[POSX:.+]] = arith.mulf %[[SIGN]], %arg0 : f32
diff --git a/mlir/test/mlir-cpu-runner/test-expand-math-approx.mlir b/mlir/test/mlir-cpu-runner/test-expand-math-approx.mlir
index 541a201c94c58..e2229a392bbf7 100644
--- a/mlir/test/mlir-cpu-runner/test-expand-math-approx.mlir
+++ b/mlir/test/mlir-cpu-runner/test-expand-math-approx.mlir
@@ -683,6 +683,24 @@ func.func @cosh() {
  return
 }
 
+// -------------------------------------------------------------------------- //
+// Tanh.
+// -------------------------------------------------------------------------- //
+
+func.func @tanh_8xf32(%a : vector<8xf32>) {
+  %r = math.tanh %a : vector<8xf32>
+  vector.print %r : vector<8xf32>
+  return
+}
+
+func.func @tanh() {
+  // CHECK: -1, -0.761594, -0.291313, 0, 0.291313, 0.761594, 1, 1
+  %v3 = arith.constant dense<[0xff800000, -1.0, -0.3, 0.0, 0.3, 1.0, 10.0, 0x7f800000]> : vector<8xf32>
+  call @tanh_8xf32(%v3) : (vector<8xf32>) -> ()
+
+ return
+}
+
 func.func @main() {
   call @exp2f() : () -> ()
   call @roundf() : () -> ()
@@ -690,5 +708,6 @@ func.func @main() {
   call @roundeven() : () -> ()
   call @sinh() : () -> ()
   call @cosh() : () -> ()
+  call @tanh() : () -> ()
   return
 }