[clang] [clang][bytecode] Don't emit checkNull for function pointers (PR #164376)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

Diagnose them later when we try to call the function pointer.

---
Full diff: https://github.com/llvm/llvm-project/pull/164376.diff


2 Files Affected:

- (modified) clang/lib/AST/ByteCode/Compiler.cpp (+1-1) 
- (added) clang/test/AST/ByteCode/cxx14.cpp (+9) 


``````````diff
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 74cae030bb9bb..28b9d84f6a76d 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -6633,7 +6633,7 @@ bool Compiler<Emitter>::VisitUnaryOperator(const UnaryOperator *E) {
     if (!this->visit(SubExpr))
       return false;
 
-    if (!this->emitCheckNull(E))
+    if (!SubExpr->getType()->isFunctionPointerType() && !this->emitCheckNull(E))
       return false;
 
     if (classifyPrim(SubExpr) == PT_Ptr)
diff --git a/clang/test/AST/ByteCode/cxx14.cpp b/clang/test/AST/ByteCode/cxx14.cpp
new file mode 100644
index 0000000000000..9622311e100cb
--- /dev/null
+++ b/clang/test/AST/ByteCode/cxx14.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -std=c++14 -verify=both,expected %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -std=c++14 -verify=both,ref      %s
+
+
+
+constexpr int(*null_ptr)() = nullptr;
+constexpr int test4 = (*null_ptr)(); // both-error {{must be initialized by a constant expression}} \
+                                     // both-note {{evaluates to a null function pointer}}
+

``````````

</details>


https://github.com/llvm/llvm-project/pull/164376