[MLIR][Arith] add and(a, or(a,b)) folder

Author: wsmoses

mlir/lib/Dialect/Arith/IR/ArithOps.cpp

@@ -896,6 +896,18 @@ OpFoldResult arith::AndIOp::fold(FoldAdaptor adaptor) {
   if (Value result = foldAndIofAndI(*this))
     return result;
 
+  /// and(a, or(a, b)) -> a
+  for (int i = 0; i < 2; i++) {
+    auto a = getOperand(1 - i);
+    if (auto orOp = getOperand(i).getDefiningOp<arith::OrIOp>()) {
+      for (int j = 0; j < 2; j++) {
+        if (orOp->getOperand(j) == a) {
+          return a;
+        }
+      }
+    }
+  }
+
   return constFoldBinaryOp<IntegerAttr>(
       adaptor.getOperands(),
       [](APInt a, const APInt &b) { return std::move(a) & b; });

mlir/test/Dialect/Arith/canonicalize.mlir

@@ -2901,6 +2901,15 @@ func.func @andand3(%a : i32, %b : i32) -> i32 {
   return %res : i32
 }
 
+// CHECK-LABEL: @andor
+//  CHECK-SAME:   (%[[A:.*]]: i32, %[[B:.*]]: i32)
+//       CHECK:   return %[[A]]
+func.func @andor(%a : i32, %b : i32) -> i32 {
+  %c = arith.ori %a, %b : i32
+  %res = arith.andi %a, %b : i32
+  return %res : i32
+}
+
 // -----
 
 // CHECK-LABEL: @truncIShrSIToTrunciShrUI