[mlir] Add attribute constraints for sorted order.

We often have constraints for array attributes that they are sorted
non-decreasing or strictly increasing. This change adds AttrConstraint classes
that support DenseArrayAttr for integer types.

Differential Revision: https://reviews.llvm.org/D134944

Author: akuegel

mlir/include/mlir/IR/OpBase.td

@@ -1636,6 +1636,21 @@ class ArrayCount<int n> : AttrConstraint<
     CPred<"$_self.cast<::mlir::ArrayAttr>().size() == " #n>,
     "with exactly " # n # " elements">;
 
+class DenseArraySorted<DenseArrayAttrBase arrayType> : AttrConstraint<
+    CPred<"llvm::is_sorted($_self.cast<" # arrayType # ">().asArrayRef())">,
+    "should be in non-decreasing order">;
+
+class DenseArrayStrictlySorted<DenseArrayAttrBase arrayType> : AttrConstraint<
+    And<[
+      CPred<"llvm::is_sorted($_self.cast<" # arrayType # ">().asArrayRef())">,
+      // Check that no two adjacent elements are the same.
+      CPred<"[](" # arrayType.returnType # " a) {\n"
+        "return std::adjacent_find(std::begin(a), std::end(a)) == "
+        "std::end(a);\n"
+        "}($_self.cast<" # arrayType # ">().asArrayRef())"
+      >]>,
+    "should be in increasing order">;
+
 class IntArrayNthElemEq<int index, int value> : AttrConstraint<
     And<[
       CPred<"$_self.cast<::mlir::ArrayAttr>().size() > " # index>,

mlir/test/IR/attribute.mlir

@@ -633,6 +633,41 @@ func.func @dense_array_attr() attributes {
 
 // -----
 
+func.func @testConfinedDenseArrayAttr() {
+  "test.confined_dense_array_attr"() {
+    i64attr = array<i64: 0, 2, 3>,
+    i32attr = array<i32: 1>,
+    emptyattr = array<i16>
+  } : () -> ()
+  func.return
+}
+
+// -----
+
+func.func @testConfinedDenseArrayAttrDuplicateValues() {
+  // expected-error@+1{{'test.confined_dense_array_attr' op attribute 'i64attr' failed to satisfy constraint: i64 dense array attribute should be in increasing order}}
+  "test.confined_dense_array_attr"() {
+    emptyattr = array<i16>,
+    i32attr = array<i32: 1, 1>,
+    i64attr = array<i64: 0, 2, 2>
+  } : () -> ()
+  func.return
+}
+
+// -----
+
+func.func @testConfinedDenseArrayAttrDecreasingOrder() {
+  // expected-error@+1{{'test.confined_dense_array_attr' op attribute 'i32attr' failed to satisfy constraint: i32 dense array attribute should be in non-decreasing order}}
+  "test.confined_dense_array_attr"() {
+    emptyattr = array<i16>,
+    i32attr = array<i32: 1, 0>,
+    i64attr = array<i64: 0, 2, 3>
+  } : () -> ()
+  func.return
+}
+
+// -----
+
 //===----------------------------------------------------------------------===//
 // Test SymbolRefAttr
 //===----------------------------------------------------------------------===//

mlir/test/lib/Dialect/Test/TestOps.td

@@ -303,6 +303,17 @@ def DenseArrayAttrOp : TEST_Op<"dense_array_attr"> {
   }];
 }
 
+def ConfinedDenseArrayAttrOp : TEST_Op<"confined_dense_array_attr"> {
+  let arguments = (ins
+      ConfinedAttr<DenseI16ArrayAttr,
+                   [DenseArrayStrictlySorted<DenseI16ArrayAttr>]>:$emptyattr,
+      ConfinedAttr<DenseI32ArrayAttr,
+                   [DenseArraySorted<DenseI32ArrayAttr>]>:$i32attr,
+      ConfinedAttr<DenseI64ArrayAttr,
+                   [DenseArrayStrictlySorted<DenseI64ArrayAttr>]>:$i64attr
+  );
+}
+
 //===----------------------------------------------------------------------===//
 // Test Enum Attributes
 //===----------------------------------------------------------------------===//