hintonda added a comment.
In D59802#1443527 <https://reviews.llvm.org/D59802#1443527>, @aaron.ballman
wrote:
> Would it make sense to transform `if (dyn_cast_or_null<T>(Obj))` into `if
> (Obj && isa<T>(Obj))` or are there bad transformations from that?
Sure, that sounds reasonable. I only see about 12 cases across all repos, so
it isn't that common. Whereas the idiom you present is used quite often.
I haven't looked yet, but wouldn't the use of `isa_or_null<>` be more efficient
in cases like this?
./clang/lib/Sema/AnalysisBasedWarnings.cpp:401: if (B->getTerminator()
&& isa<CXXTryStmt>(B->getTerminator()))
./clang/lib/AST/Expr.cpp:2734: if (MCE->getMethodDecl() &&
isa<CXXConversionDecl>(MCE->getMethodDecl()))
Granted, there aren't a lot of these.
>
>
>> Btw, I also found the same pattern used for `while()`, so I'll add that too.
>> Here's a sample of the patterns I'm seeing:
>>
>> ./lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp:213:
>> while (dyn_cast<NullStmt>(last_stmt)) {
>
> Hah, good catch!
>
>> ./clang/lib/CodeGen/CodeGenModule.cpp:1390: if
>> (dyn_cast_or_null<NamedDecl>(D)) . // <--- this one's okay
>
> I think this could be expressed as `if (D && isa<NamedDecl>(D))`, no?
Repository:
rG LLVM Github Monorepo
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https://reviews.llvm.org/D59802/new/
https://reviews.llvm.org/D59802
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