[PATCH] D13157: Teach -Wtautological-overlap-compare about enums

[George Burgess IV via cfe-commits]

george.burgess.iv closed this revision.
george.burgess.iv marked 4 inline comments as done.
george.burgess.iv added a comment.

Changed code to address all feedback + committed as r249053. Thanks for the reviews!


================
Comment at: lib/Analysis/CFG.cpp:49
@@ +48,3 @@
+tryNormalizeBinaryOperator(const BinaryOperator *B) {
+  auto TryTransformToIntOrEnumConstant = [](const Expr *E) -> const Expr * {
+    E = E->IgnoreParens();
----------------
rtrieu wrote:
> Why is this a lambda instead of a helper function?
Because it's small + super specific to `tryNormalizeBinaryOperator`, and making it a lambda lets me scope it it only to where it's useful. It's now a helper function. :)

================
Comment at: lib/Analysis/CFG.cpp:99-104
@@ +98,8 @@
+  // Currently we're only given EnumConstantDecls or IntegerLiterals
+  auto *C1 = cast<EnumConstantDecl>(cast<DeclRefExpr>(A)->getDecl());
+  auto *C2 = cast<EnumConstantDecl>(cast<DeclRefExpr>(B)->getDecl());
+
+  const TagDecl *E1 = TagDecl::castFromDeclContext(C1->getDeclContext());
+  const TagDecl *E2 = TagDecl::castFromDeclContext(C2->getDeclContext());
+  return E1 == E2;
+}
----------------
rtrieu wrote:
> There's a few extra casts in here, plus some blind conversions between types.  Add your assumptions for the types in asserts.  Also, DeclContext should use cast<> to get to Decl types.  I recommend the following:
> 
> ```
>   assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
>   auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
>   auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
> 
>   assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
>   const DeclContext *DC1 = Decl1->getDeclContext();
>   const DeclContext *DC2 = Decl2->getDeclContext();
> 
>   assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
>   return DC1 == DC2;
> 
> ```
I was under the impression that the `cast<Foo>(Bar)` asserts `isa<Foo>(Bar)` for me, so I thought that asserts like those would just be redundant. Changed to your version anyway :)


http://reviews.llvm.org/D13157