[mlir][Math] Support fold SqrtOp with constant dense.

[jacquesguan]

Summary

This patch uses constFoldUnaryOpConditional to replace current folder in order to support constant dense.

[rriddle]

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

129–138

Can this be a switch instead?

[jacquesguan]

Address comment.

[jacquesguan]

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

129–138

Done.

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

return constFoldBinaryOpConditional<FloatAttr>(
         if (a.getSizeInBits(a.getSemantics()) == 32 &&
             b.getSizeInBits(b.getSemantics()) == 32)
           return APFloat(powf(a.convertToFloat(), b.convertToFloat()));
 
         return {};
       });
 }
 
-OpFoldResult math::SqrtOp::fold(ArrayRef<Attribute> operands) {
-  auto constOperand = operands.front();
-  if (!constOperand)
-    return {};
-
-  auto attr = constOperand.dyn_cast<FloatAttr>();
-  if (!attr)
-    return {};
-
-  auto ft = getType().cast<FloatType>();
-
-  APFloat apf = attr.getValue();
+//===----------------------------------------------------------------------===//
+// SqrtOp folder
+//===----------------------------------------------------------------------===//
 
-  if (apf.isNegative())
+OpFoldResult math::SqrtOp::fold(ArrayRef<Attribute> operands) {
+  return constFoldUnaryOpConditional<FloatAttr>(
+      operands, [](const APFloat &a) -> Optional<APFloat> {
+        if (a.isNegative())
           return {};
 
-  if (ft.getWidth() == 64)
-    return FloatAttr::get(getType(), sqrt(apf.convertToDouble()));
-
-  if (ft.getWidth() == 32)
-    return FloatAttr::get(getType(), sqrtf(apf.convertToFloat()));
-
+        switch (a.getSizeInBits(a.getSemantics())) {
+        case 64:
+          return APFloat(sqrt(a.convertToDouble()));
+        case 32:
+          return APFloat(sqrtf(a.convertToFloat()));
+        default:
           return {};
         }
+      });
+}
 
 /// Materialize an integer or floating point constant.
 Operation *math::MathDialect::materializeConstant(OpBuilder &builder,
                                                   Attribute value, Type type,
                                                   Location loc) {
   return builder.create<arith::ConstantOp>(loc, value, type);
 }

mlir/test/Dialect/Math/canonicalize.mlir

 // CHECK: %[[cst:.+]] = arith.constant 2.000000e+00 : f32
 // CHECK: return %[[cst]]
 func.func @sqrt_fold() -> f32 {
   %c = arith.constant 4.0 : f32
   %r = math.sqrt %c : f32
   return %r : f32
 }
 
+// CHECK-LABEL: @sqrt_fold_vec
+// CHECK: %[[cst:.+]] = arith.constant dense<[1.000000e+00, 1.41421354, 1.73205078, 2.000000e+00]> : vector<4xf32>
+// CHECK: return %[[cst]]
+func.func @sqrt_fold_vec() -> (vector<4xf32>) {
+  %v1 = arith.constant dense<[1.0, 2.0, 3.0, 4.0]> : vector<4xf32>
+  %0 = math.sqrt %v1 : vector<4xf32>
+  return %0 : vector<4xf32>
+}
+
 // CHECK-LABEL: @abs_fold
 // CHECK: %[[cst:.+]] = arith.constant 4.000000e+00 : f32
 // CHECK: return %[[cst]]
 func.func @abs_fold() -> f32 {
   %c = arith.constant -4.0 : f32
   %r = math.abs %c : f32
   return %r : f32
 }