[PATCH] D156175: [clang][ConstExprEmitter] handle NullToPointer ImplicitCastExpr

[Eli Friedman via Phabricator via cfe-commits]

efriedma added inline comments.


================
Comment at: clang/lib/CodeGen/CGExprConstant.cpp:1131-1132
+    case CK_NullToPointer: {
+      if (llvm::Constant *C = Visit(subExpr, destType))
+        if (C->isNullValue())
+          return CGM.EmitNullConstant(destType);
----------------
nickdesaulniers wrote:
> FWIW, I would have thought these might be unnecessary, but we do trip 2 tests without these guards IIRC.
The fact that the Visit can fail doesn't surprise me; you can write arbitrary expressions of type nullptr_t (for example, `nullptr_t f(); void* g = f();`.  I can't think of any reason you'd need to check C->isNullValue(), though; do you have a testcase for that?


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  https://reviews.llvm.org/D156175/new/

https://reviews.llvm.org/D156175