[PATCH] D119375: [Clang][Sema] Do not evaluate value-dependent immediate invocations

[Evgeny Shulgin via Phabricator via cfe-commits]

Izaron updated this revision to Diff 407564.
Izaron added a comment.

Add test comments


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119375/new/

https://reviews.llvm.org/D119375

Files:
  clang/lib/Sema/SemaExpr.cpp
  clang/test/SemaCXX/cxx2a-consteval.cpp


Index: clang/test/SemaCXX/cxx2a-consteval.cpp
===================================================================
--- clang/test/SemaCXX/cxx2a-consteval.cpp
+++ clang/test/SemaCXX/cxx2a-consteval.cpp
@@ -613,6 +613,32 @@
 
 } // namespace unevaluated
 
+namespace value_dependent {
+
+consteval int foo(int x) {
+  return x;
+}
+
+template <int X> constexpr int bar() {
+  // Previously this call was rejected as value-dependent constant expressions
+  // can't be immediately evaluated. Now we show that we don't immediately
+  // evaluate them until they are instantiated.
+  return foo(X);
+}
+
+template <typename T> constexpr int baz() {
+  constexpr int t = sizeof(T);
+  // Previously this call was rejected as `t` is value-dependent and its value
+  // is unknown until the function is instantiated. Now we show that we don't
+  // reject such calls.
+  return foo(t);
+}
+
+static_assert(bar<15>() == 15);
+static_assert(baz<int>() == sizeof(int));
+
+} // namespace value_dependent
+
 namespace PR50779 {
 struct derp {
   int b = 0;
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -16747,7 +16747,10 @@
       ConstantExpr::getStorageKind(Decl->getReturnType().getTypePtr(),
                                    getASTContext()),
       /*IsImmediateInvocation*/ true);
-  ExprEvalContexts.back().ImmediateInvocationCandidates.emplace_back(Res, 0);
+  /// Value-dependent constant expressions should not be immediately
+  /// evaluated until they are instantiated.
+  if (!Res->isValueDependent())
+    ExprEvalContexts.back().ImmediateInvocationCandidates.emplace_back(Res, 0);
   return Res;
 }
 


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