Author: Corentin Jabot Date: 2022-07-24T16:18:12+02:00 New Revision: c68baa73eb437556cd8abe40902182a6034930ac
URL: https://github.com/llvm/llvm-project/commit/c68baa73eb437556cd8abe40902182a6034930ac DIFF: https://github.com/llvm/llvm-project/commit/c68baa73eb437556cd8abe40902182a6034930ac.diff LOG: [clang] Fix incorrect constant folding of `if consteval` Fixes https://github.com/llvm/llvm-project/issues/55638. `if consteval` was evaluated incorrectly when in a non-constant context that could be constant-folded. Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D130437 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/AST/ExprConstant.cpp clang/test/CodeGenCXX/cxx2b-consteval-if.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index ac6c5bb543121..af64152666757 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -194,6 +194,8 @@ Bug Fixes move assignment operator. Fixes `Issue 56456 <https://github.com/llvm/llvm-project/issues/56456>`_. - Fixed a crash when a variable with a bool enum type that has no definition used in comparison operators. Fixes `Issue 56560 <https://github.com/llvm/llvm-project/issues/56560>`_. +- Fix that ``if consteval`` could evaluate to ``true`` at runtime because it was incorrectly + constant folded. Fixes `Issue 55638 <https://github.com/llvm/llvm-project/issues/55638>`_. Improvements to Clang's diagnostics ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 6ffb65d8e71d3..9d92c848ccb84 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -5266,10 +5266,14 @@ static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, } } bool Cond; - if (IS->isConsteval()) + if (IS->isConsteval()) { Cond = IS->isNonNegatedConsteval(); - else if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), - Cond)) + // If we are not in a constant context, if consteval should not evaluate + // to true. + if (!Info.InConstantContext) + Cond = !Cond; + } else if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), + Cond)) return ESR_Failed; if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) { diff --git a/clang/test/CodeGenCXX/cxx2b-consteval-if.cpp b/clang/test/CodeGenCXX/cxx2b-consteval-if.cpp index 2e38ce0e63639..a69a2271f661b 100644 --- a/clang/test/CodeGenCXX/cxx2b-consteval-if.cpp +++ b/clang/test/CodeGenCXX/cxx2b-consteval-if.cpp @@ -26,3 +26,30 @@ constexpr void f() { void g() { f(); } + +namespace GH55638 { + +constexpr bool is_constant_evaluated() noexcept { + if consteval { return true; } else { return false; } +} + +constexpr int compiletime(int) { + return 2; +} + +constexpr int runtime(int) { + return 1; +} + +constexpr int test(int x) { + if(is_constant_evaluated()) + return compiletime(x); // CHECK-NOT: call {{.*}}compiletime + return runtime(x); // CHECK: call {{.*}}runtime +} + +int f(int x) { + x = test(x); + return x; +} + +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
