llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: ofAlpaca (ofAlpaca) <details> <summary>Changes</summary> Resolves #<!-- -->102064 I think the problem is that the function `bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp)` return default `false` directly when visiting expression of `__noop`. Thus, `__noop` cannot be evaluated as constant initializer in here. https://github.com/llvm/llvm-project/blob/b6603e1bf11dee4761e49af6581c8b8f074b705d/clang/lib/Sema/SemaDecl.cpp#L14402 By adding a `BI__noop` case in `bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp)` should fix the problem. Correct me if there is anything I misunderstood. --- Full diff: https://github.com/llvm/llvm-project/pull/105983.diff 4 Files Affected: - (modified) clang/docs/ReleaseNotes.rst (+2) - (modified) clang/include/clang/Basic/Builtins.td (+1-1) - (modified) clang/lib/AST/ExprConstant.cpp (+4) - (added) clang/test/SemaCXX/GH102064.cpp (+3) ``````````diff diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 971df672b6ca1e..e60407061ccd3b 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -861,6 +861,8 @@ Bug Fixes to Compiler Builtins - Clang now allows pointee types of atomic builtin arguments to be complete template types that was not instantiated elsewhere. +- Fix ``__noop`` not marked as constexpr. (#GH102064) + Bug Fixes to Attribute Support ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td index f5b15cf90d1f83..b42f7ea1d9de68 100644 --- a/clang/include/clang/Basic/Builtins.td +++ b/clang/include/clang/Basic/Builtins.td @@ -2516,7 +2516,7 @@ def IsoVolatileStore : MSLangBuiltin, Int8_16_32_64Template { def Noop : MSLangBuiltin { let Spellings = ["__noop"]; - let Attributes = [NoThrow]; + let Attributes = [NoThrow, Constexpr]; let Prototype = "int(...)"; } diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 5af712dd7257b1..d505346bccd9b3 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -12586,6 +12586,10 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, return false; } + case Builtin::BI__noop: + // __noop always evaluates successfully + return true; + case Builtin::BI__builtin_is_constant_evaluated: { const auto *Callee = Info.CurrentCall->getCallee(); if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression && diff --git a/clang/test/SemaCXX/GH102064.cpp b/clang/test/SemaCXX/GH102064.cpp new file mode 100644 index 00000000000000..0ed930439e3d75 --- /dev/null +++ b/clang/test/SemaCXX/GH102064.cpp @@ -0,0 +1,3 @@ +// RUN: %clang_cc1 -std=c++20 -fms-extensions %s +// expected-no-diagnostics +constexpr int x = []{ __noop; return 0; }(); `````````` </details> https://github.com/llvm/llvm-project/pull/105983 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
