Author: rsmith Date: Fri Sep 20 16:08:59 2019 New Revision: 372437 URL: http://llvm.org/viewvc/llvm-project?rev=372437&view=rev Log: Fix assertion failure when constant evaluation of a switch jumps over an uninitialized variable in an init-statement of a 'for' or 'if'.
Modified: cfe/trunk/lib/AST/ExprConstant.cpp cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp Modified: cfe/trunk/lib/AST/ExprConstant.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=372437&r1=372436&r2=372437&view=diff ============================================================================== --- cfe/trunk/lib/AST/ExprConstant.cpp (original) +++ cfe/trunk/lib/AST/ExprConstant.cpp Fri Sep 20 16:08:59 2019 @@ -4131,6 +4131,21 @@ static EvalStmtResult EvaluateStmt(StmtR // preceded by our switch label. BlockScopeRAII Scope(Info); + // Step into the init statement in case it brings an (uninitialized) + // variable into scope. + if (const Stmt *Init = IS->getInit()) { + EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); + if (ESR != ESR_CaseNotFound) { + assert(ESR != ESR_Succeeded); + return ESR; + } + } + + // Condition variable must be initialized if it exists. + // FIXME: We can skip evaluating the body if there's a condition + // variable, as there can't be any case labels within it. + // (The same is true for 'for' statements.) + EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case); if (ESR != ESR_CaseNotFound || !IS->getElse()) return ESR; @@ -4147,6 +4162,18 @@ static EvalStmtResult EvaluateStmt(StmtR case Stmt::ForStmtClass: { const ForStmt *FS = cast<ForStmt>(S); + BlockScopeRAII Scope(Info); + + // Step into the init statement in case it brings an (uninitialized) + // variable into scope. + if (const Stmt *Init = FS->getInit()) { + EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); + if (ESR != ESR_CaseNotFound) { + assert(ESR != ESR_Succeeded); + return ESR; + } + } + EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody(), Case); if (ESR != ESR_Continue) Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp?rev=372437&r1=372436&r2=372437&view=diff ============================================================================== --- cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp (original) +++ cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp Fri Sep 20 16:08:59 2019 @@ -620,4 +620,17 @@ namespace Uninit { constexpr int s1 = switch_var(1); constexpr int s2 = switch_var(2); static_assert(s1 == 1 && s2 == 2); + + constexpr bool switch_into_init_stmt() { + switch (1) { + if (int n; false) { + for (int m; false;) { + case 1: + n = m = 1; + return n == 1 && m == 1; + } + } + } + } + static_assert(switch_into_init_stmt()); } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits