[CIR] Infer MLIRContext in attr builders when possible (llvm#136741)

Mirrors incubator changes from llvm/clangir#1582

Author: xlauko

clang/include/clang/CIR/Dialect/Builder/CIRBaseBuilder.h

@@ -166,8 +166,7 @@ class CIRBaseBuilderTy : public mlir::OpBuilder {
   mlir::TypedAttr getConstPtrAttr(mlir::Type type, int64_t value) {
     auto valueAttr = mlir::IntegerAttr::get(
         mlir::IntegerType::get(type.getContext(), 64), value);
-    return cir::ConstPtrAttr::get(
-        getContext(), mlir::cast<cir::PointerType>(type), valueAttr);
+    return cir::ConstPtrAttr::get(type, valueAttr);
   }
 
   mlir::Value createAlloca(mlir::Location loc, cir::PointerType addrType,

clang/include/clang/CIR/Dialect/IR/CIRAttrs.td

@@ -202,6 +202,11 @@ def ConstArrayAttr : CIR_Attr<"ConstArray", "const_array", [TypedAttrInterface]>
         zeros = typeSize - mlir::cast<mlir::ArrayAttr>(elts).size();
 
       return $_get(type.getContext(), type, elts, zeros);
+    }]>,
+    AttrBuilderWithInferredContext<(ins "cir::ArrayType":$type,
+                                        "mlir::Attribute":$elts,
+                                        "int":$trailingZerosNum), [{
+      return $_get(type.getContext(), type, elts, trailingZerosNum);
     }]>
   ];
 
@@ -234,11 +239,7 @@ def ConstPtrAttr : CIR_Attr<"ConstPtr", "ptr", [TypedAttrInterface]> {
                                         "mlir::IntegerAttr":$value), [{
       return $_get(type.getContext(), mlir::cast<cir::PointerType>(type),
                    value);
-    }]>,
-    AttrBuilder<(ins "mlir::Type":$type,
-                     "mlir::IntegerAttr":$value), [{
-      return $_get($_ctxt, mlir::cast<cir::PointerType>(type), value);
-    }]>,
+    }]>
   ];
   let extraClassDeclaration = [{
     bool isNullValue() const { return getValue().getInt() == 0; }