[PATCH] D31757: [clang-tidy] Add a clang-tidy check for possible inefficient vector operations

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


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Comment at: clang-tidy/performance/InefficientVectorOperationCheck.cpp:109-111
+  auto AllVectorVarRefs = utils::decl_ref_expr::allDeclRefExprs(
+      *VectorVarDecl, *LoopParent, *Result.Context);
+  for (const auto *Ref : AllVectorVarRefs) {
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hokein wrote:
> aaron.ballman wrote:
> > aaron.ballman wrote:
> > > I'm not certain what types are being used here. Can you turn `AllVectorVarRefs` into something with an explicit type so that I can know what `Ref`'s type is?
> > I may not have been clear -- I don't mean that the variable name should contain type information, I mean that the type should not be automatically deduced. We only use `auto` when the type is spelled explicitly in the initialization or is otherwise obvious from context (like range-based for loops).
> I'd prefer to use `auto` to initialize `AllVectorVarRefExprs`, as its type is `SmallPtrSet<const DeclRefExpr *, 16>`, which is a long and noisy name. Using `auto` can increases readability here.
It doesn't increase readability when someone reviewing the code has no idea what types are involved and has to ask you for clarification. `auto` should only be used when the type is obvious from the context or spelling the type is *really* noisy. A single level of template goop is a very small amount of noise.


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Comment at: clang-tidy/performance/InefficientVectorOperationCheck.cpp:116
+      *VectorVarDecl, *LoopParent, *Result.Context);
+  for (const DeclRefExpr* RefExpr : AllVectorVarRefExprs) {
+    // Skip cases where there are usages (defined as DeclRefExpr that refers to
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Formatting (and you can use `auto` here once you correct the type above).


https://reviews.llvm.org/D31757