[clang] [clang][bytecode] Fix reinterpret casts of two non-primitive types (PR #107564)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

We don't want to allow e.g. cast from a record to an array or the other way arround.

---
Full diff: https://github.com/llvm/llvm-project/pull/107564.diff


1 Files Affected:

- (modified) clang/lib/AST/ByteCode/Compiler.cpp (+9-2) 


``````````diff
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index a831f196abdcb5..c376dd8325fe2e 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -2478,8 +2478,15 @@ bool Compiler<Emitter>::VisitCXXReinterpretCastExpr(
     const CXXReinterpretCastExpr *E) {
   const Expr *SubExpr = E->getSubExpr();
 
-  bool TypesMatch = classify(E) == classify(SubExpr);
-  if (!this->emitInvalidCast(CastKind::Reinterpret, /*Fatal=*/!TypesMatch, E))
+  bool Fatal = false;
+  std::optional<PrimType> FromT = classify(SubExpr);
+  std::optional<PrimType> ToT = classify(E);
+  if (!FromT || !ToT)
+    Fatal = true;
+  else
+    Fatal = (ToT != FromT);
+
+  if (!this->emitInvalidCast(CastKind::Reinterpret, Fatal, E))
     return false;
 
   return this->delegate(SubExpr);

``````````

</details>


https://github.com/llvm/llvm-project/pull/107564