add baseline signi/signf ops

Author: j2kun

mlir/include/mlir/Dialect/Math/IR/MathOps.td

@@ -437,6 +437,45 @@ def Math_CoshOp : Math_FloatUnaryOp<"cosh"> {
   let hasFolder = 1;
 }
 
+//===----------------------------------------------------------------------===//
+// SignIOp
+//===----------------------------------------------------------------------===//
+
+def Math_SignIOp : Math_IntegerUnaryOp<"signi"> {
+  let summary = "ternary-valued sign of an integer";
+  let description = [{
+    The `signi` operation computes -1 if the operand is negative, 0 if it is
+    zero, and 1 if it is positive.
+
+    Example:
+
+    ```mlir
+    %a = math.signi %b : i64
+    ```
+  }];
+  let hasFolder = 1;
+}
+
+
+//===----------------------------------------------------------------------===//
+// SignFOp
+//===----------------------------------------------------------------------===//
+
+def Math_SignFOp : Math_FloatUnaryOp<"signf"> {
+  let summary = "ternary-valued sign of a floating point value";
+  let description = [{
+    The `signf` operation computes -1.0 if the operand is negative, 0.0 if it
+    is zero, 1.0 if it is positive, and `NaN` if the operand is `NaN`.
+
+    Example:
+
+    ```mlir
+    %a = math.signf %b : f32
+    ```
+  }];
+  let hasFolder = 1;
+}
+
 //===----------------------------------------------------------------------===//
 // SinOp
 //===----------------------------------------------------------------------===//

mlir/lib/Dialect/Math/IR/MathOps.cpp

@@ -266,6 +266,34 @@ OpFoldResult math::SinOp::fold(FoldAdaptor adaptor) {
       });
 }
 
+//===----------------------------------------------------------------------===//
+// SignIOp folder
+//===----------------------------------------------------------------------===//
+
+OpFoldResult math::SignIOp::fold(FoldAdaptor adaptor) {
+  return constFoldUnaryOp<IntegerAttr>(
+      adaptor.getOperands(), [](const APInt &a) {
+        return a.isNegative() ? APInt(a.getBitWidth(), -1)
+                              : (a.isZero() ? APInt(a.getBitWidth(), 0)
+                                            : APInt(a.getBitWidth(), 1));
+      });
+}
+
+//===----------------------------------------------------------------------===//
+// SignFOp folder
+//===----------------------------------------------------------------------===//
+
+OpFoldResult math::SignFOp::fold(FoldAdaptor adaptor) {
+  return constFoldUnaryOp<FloatAttr>(
+      adaptor.getOperands(), [](const APFloat &a) {
+        if (a.isNaN())
+          return APFloat::getNaN(a.getSemantics());
+        return a.isNegative() ? APFloat(a.getSemantics(), -1)
+                              : (a.isZero() ? APFloat(a.getSemantics(), 0)
+                                            : APFloat(a.getSemantics(), 1));
+      });
+}
+
 //===----------------------------------------------------------------------===//
 // SinhOp folder
 //===----------------------------------------------------------------------===//