70 lines · cpp
1// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify=ref %s2// RUN: %clang_cc1 -std=c++20 -fsyntax-only -fexperimental-new-constant-interpreter -verify %s3 4/// This is a version of the nqueens.cpp from SemaCXX/,5/// but we don't initialize the State variable in the6/// Board constructors.7/// This tests that InterpFrame::describe().8 9typedef unsigned long uint64_t;10 11struct Board {12 uint64_t State;13 bool Failed;14 15 constexpr Board() : Failed(false) {}16 constexpr Board(const Board &O) : Failed(O.Failed) {}17 constexpr Board(uint64_t State, bool Failed = false) :18 Failed(Failed) {}19 constexpr Board addQueen(int Row, int Col) const {20 return Board(State | ((uint64_t)Row << (Col * 4))); // ref-note {{read of uninitialized object}} \21 // expected-note {{read of uninitialized object}}22 }23 constexpr int getQueenRow(int Col) const {24 return (State >> (Col * 4)) & 0xf;25 }26 constexpr bool ok(int Row, int Col) const {27 return okRecurse(Row, Col, 0);28 }29 constexpr bool okRecurse(int Row, int Col, int CheckCol) const {30 return Col == CheckCol ? true :31 getQueenRow(CheckCol) == Row ? false :32 getQueenRow(CheckCol) == Row + (Col - CheckCol) ? false :33 getQueenRow(CheckCol) == Row + (CheckCol - Col) ? false :34 okRecurse(Row, Col, CheckCol + 1);35 }36 constexpr bool at(int Row, int Col) const {37 return getQueenRow(Col) == Row;38 }39 constexpr bool check(const char *, int=0, int=0) const;40};41 42constexpr Board buildBoardRecurse(int N, int Col, const Board &B);43constexpr Board buildBoardScan(int N, int Col, int Row, const Board &B);44constexpr Board tryBoard(const Board &Try,45 int N, int Col, int Row, const Board &B) {46 return Try.Failed ? buildBoardScan(N, Col, Row, B) : Try;47}48constexpr Board buildBoardScan(int N, int Col, int Row, const Board &B) {49 return Row == N ? Board(0, true) :50 B.ok(Row, Col) ?51 tryBoard(buildBoardRecurse(N, Col + 1, B.addQueen(Row, Col)), // ref-note {{in call to 'B.addQueen(0, 0)}} \52 // expected-note {{in call to 'B.addQueen(0, 0)}}53 N, Col, Row+1, B) :54 buildBoardScan(N, Col, Row + 1, B);55}56constexpr Board buildBoardRecurse(int N, int Col, const Board &B) {57 return Col == N ? B : buildBoardScan(N, Col, 0, B); // ref-note {{in call to 'buildBoardScan(8, 0, 0, Board())'}} \58 // expected-note {{in call to 'buildBoardScan(8, 0, 0, Board())'}}59 60}61constexpr Board buildBoard(int N) {62 return buildBoardRecurse(N, 0, Board()); // ref-note {{in call to 'buildBoardRecurse(8, 0, Board())'}} \63 // expected-note {{in call to 'buildBoardRecurse(8, 0, Board())'}}64}65 66constexpr Board q8 = buildBoard(8); // ref-error {{must be initialized by a constant expression}} \67 // ref-note {{in call to 'buildBoard(8)'}} \68 // expected-error {{must be initialized by a constant expression}} \69 // expected-note {{in call to 'buildBoard(8)'}}70