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Revert "[LLVM][Casting.h] Add trivial self-cast" 

This reverts commit 0809f63826.  The patch appears not to have included corresponding isa<Ty> support.

This was revealed when reintroducing the required isa<Ty> asserts in cast<Ty>.  See https://discourse.llvm.org/t/cast-x-is-broken-implications-and-proposal-to-address/63033 for context.

Here's the template instantiation error:
In file included from /home/preames/llvm-repo/llvm-project/llvm/unittests/Support/Casting.cpp:9:
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h: In instantiation of ‘static bool llvm::isa_impl<To, From, Enabler>::doit(const From&) [with To = llvm::bar*; From = llvm::bar; Enabler = void]’:
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:110:36:   required from ‘static bool llvm::isa_impl_cl<To, const From*>::doit(const From*) [with To = llvm::bar*; From = llvm::bar]’
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:137:41:   required from ‘static bool llvm::isa_impl_wrap<To, FromTy, FromTy>::doit(const FromTy&) [with To = llvm::bar*; FromTy = const llvm::bar*]’
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:129:13:   required from ‘static bool llvm::isa_impl_wrap<To, From, SimpleFrom>::doit(const From&) [with To = llvm::bar*; From = const llvm::bar* const; SimpleFrom = const llvm::bar*]’
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:263:62:   required from ‘static bool llvm::CastIsPossible<To, From, Enable>::isPossible(const From&) [with To = llvm::bar*; From = const llvm::bar*; Enable = void]’
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:517:38:   required from ‘static bool llvm::CastInfo<To, From, typename std::enable_if<(! llvm::is_simple_type<From>::value), void>::type>::isPossible(From&) [with To = llvm::bar*; From = llvm::bar* const]’
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:556:46:   required from ‘bool llvm::isa(const From&) [with To = llvm::bar*; From = llvm::bar*]’
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:585:3:   required from ‘decltype(auto) llvm::cast(From*) [with To = llvm::bar*; From = llvm::bar]’
/home/preames/llvm-repo/llvm-project/llvm/unittests/Support/Casting.cpp:181:27:   required from here
/home/preames/llvm-repo/llvm-project/llvm/include/llvm/Support/Casting.h:64:64: error: ‘classof’ is not a member of ‘llvm::bar*’
   64 |   static inline bool doit(const From &Val) { return To::classof(&Val); }
This commit is contained in:
Philip Reames 2022-06-07 12:23:43 -07:00 committed by Philip Reames
parent dd2a6d78ee
commit 781de11f42
2 changed files with 1 additions and 31 deletions
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9
llvm/include/llvm/Support/Casting.h
View File

@ -192,12 +192,6 @@ template <class To, class From> struct cast_retty {
To, From, typename simplify_type<From>::SimpleType>::ret_type;
};
template <class T> struct cast_retty<T, T> {
// Casting T to itself, but have to use a ref if so we don't get a copy if
// it's not a pointer.
using ret_type = std::conditional_t<std::is_pointer<T>::value, T, T &>;
};
//===----------------------------------------------------------------------===//
// cast_convert_val
//===----------------------------------------------------------------------===//
@ -282,8 +276,7 @@ struct CastIsPossible<To, Optional<From>> {
/// always be possible.
template <typename To, typename From>
struct CastIsPossible<To, From,
std::enable_if_t<std::is_same<To, From>::value ||
std::is_base_of<To, From>::value>> {
std::enable_if_t<std::is_base_of<To, From>::value>> {
static inline bool isPossible(const From &f) { return true; }
};

23
llvm/unittests/Support/Casting.cpp
View File

@ -144,7 +144,6 @@ extern const bar *B2;
// test various configurations of const
const bar &B3 = B1;
const bar *const B4 = B2;
bar *B5 = &B;
TEST(CastingTest, isa) {
EXPECT_TRUE(isa<foo>(B1));
@ -176,17 +175,6 @@ TEST(CastingTest, cast) {
foo *F8 = B1.baz();
EXPECT_NE(F8, null_foo);
// Ensure cast-to-self works (with the type in the template verbatim
// equivalent to the type in the input).
auto B9 = cast<bar *>(B5);
static_assert(std::is_same<bar *, decltype(B9)>::value,
"Inccorrect return type!");
EXPECT_EQ(B9, B5);
auto B10 = cast<const bar *>(B2);
static_assert(std::is_same<const bar *, decltype(B10)>::value,
"Inccorrect return type!");
EXPECT_EQ(B10, B2);
std::unique_ptr<const bar> BP(B2);
auto FP = cast<foo>(std::move(BP));
static_assert(std::is_same<std::unique_ptr<const foo>, decltype(FP)>::value,
@ -224,17 +212,6 @@ TEST(CastingTest, dyn_cast) {
// EXPECT_EQ(F4, null_foo);
foo *F5 = B1.daz();
EXPECT_NE(F5, null_foo);
// Ensure cast-to-self works (with the type in the template verbatim
// equivalent to the type in the input).
auto B9 = dyn_cast<bar *>(B5);
static_assert(std::is_same<bar *, decltype(B9)>::value,
"Inccorrect return type!");
EXPECT_EQ(B9, B5);
auto B10 = dyn_cast<const bar *>(B2);
static_assert(std::is_same<const bar *, decltype(B10)>::value,
"Inccorrect return type!");
EXPECT_EQ(B10, B2);
}
// All these tests forward to dyn_cast_if_present, so they also provde an