aaron.ballman added a comment.
Personally, I think this behavior is a bit mysterious given that there are
*much* better ways to silence unused variable warnings (like casting to `void`)
that have been well-supported by compilers for a long time and I'd prefer not
to penalize every call expression for such an unusual code pattern. That said,
it should probably not be much of a performance hit, so it may be reasonable
(having compile time performance numbers pre and post patch would be nice,
though).
================
Comment at: clang/lib/Analysis/UninitializedValues.cpp:409-410
+static bool hasTrivialBody(CallExpr *CE) {
+ if (FunctionDecl *fd = CE->getDirectCallee()) {
+ if (FunctionTemplateDecl *ftd = fd->getPrimaryTemplate())
+ return ftd->getTemplatedDecl()->hasTrivialBody();
----------------
These names don't match the usual coding styles, should probably be `FD` and
`FTD`.
Also, what about calls to something other than a function, like a block?
================
Comment at: clang/lib/Analysis/UninitializedValues.cpp:435
if ((*I)->getType().isConstQualified())
- classify((*I), ConstRefUse);
+ if (!hasTrivialBody(CE))
+ classify((*I), ConstRefUse);
----------------
This can be hoisted out of the loop so that we don't have to check the same
thing on every argument.
================
Comment at: clang/test/SemaCXX/warn-uninitialized-const-reference.cpp:13
+template <class T>
+inline void ignore_template(T const &) {}
+void ignore(const int &i) {}
----------------
hans wrote:
> I think "const T &" would be the more common ordering. Also the "inline"
> isn't really necessary.
I'd also appreciate an example that explicitly shows we mean *empty* and not
*trivial*:
```
void dont_ignore_non_empty(const int &) { ; } // Calling this won't silence the
warning for you
```
Also, should we test a function try block? (I would consider those to never
have an empty body, but I don't recall how that API reports it.)
```
void ignore_function_try_block_maybe_who_knows(const int &) try {} catch (...)
{}
```
(If we add support for other callables like blocks, those should be tested as
well.)
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D82425/new/
https://reviews.llvm.org/D82425
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