These builtins are modeled on the clzg/ctzg builtins, which accept an
optional second argument. This second argument is returned if the first
argument is 0. These builtins unconditionally exhibit zero-is-undef
behaviour, regardless of target preference for the other ctz/clz
builtins. The builtins have constexpr support.
Fixes#154113
Added constant evaluation support for `__builtin_elementwise_abs` on integer, float and vector type.
fixes#152276
---------
Co-authored-by: Simon Pilgrim <llvm-dev@redking.me.uk>
This way, we can check a single uint8_t for != 0 to know whether this
block is accessible or not. If not, we still need to figure out why not
and diagnose appropriately of course.
This is a major change on how we represent nested name qualifications in
the AST.
* The nested name specifier itself and how it's stored is changed. The
prefixes for types are handled within the type hierarchy, which makes
canonicalization for them super cheap, no memory allocation required.
Also translating a type into nested name specifier form becomes a no-op.
An identifier is stored as a DependentNameType. The nested name
specifier gains a lightweight handle class, to be used instead of
passing around pointers, which is similar to what is implemented for
TemplateName. There is still one free bit available, and this handle can
be used within a PointerUnion and PointerIntPair, which should keep
bit-packing aficionados happy.
* The ElaboratedType node is removed, all type nodes in which it could
previously apply to can now store the elaborated keyword and name
qualifier, tail allocating when present.
* TagTypes can now point to the exact declaration found when producing
these, as opposed to the previous situation of there only existing one
TagType per entity. This increases the amount of type sugar retained,
and can have several applications, for example in tracking module
ownership, and other tools which care about source file origins, such as
IWYU. These TagTypes are lazily allocated, in order to limit the
increase in AST size.
This patch offers a great performance benefit.
It greatly improves compilation time for
[stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for
`test_on2.cpp` in that project, which is the slowest compiling test,
this patch improves `-c` compilation time by about 7.2%, with the
`-fsyntax-only` improvement being at ~12%.
This has great results on compile-time-tracker as well:
This patch also further enables other optimziations in the future, and
will reduce the performance impact of template specialization resugaring
when that lands.
It has some other miscelaneous drive-by fixes.
About the review: Yes the patch is huge, sorry about that. Part of the
reason is that I started by the nested name specifier part, before the
ElaboratedType part, but that had a huge performance downside, as
ElaboratedType is a big performance hog. I didn't have the steam to go
back and change the patch after the fact.
There is also a lot of internal API changes, and it made sense to remove
ElaboratedType in one go, versus removing it from one type at a time, as
that would present much more churn to the users. Also, the nested name
specifier having a different API avoids missing changes related to how
prefixes work now, which could make existing code compile but not work.
How to review: The important changes are all in
`clang/include/clang/AST` and `clang/lib/AST`, with also important
changes in `clang/lib/Sema/TreeTransform.h`.
The rest and bulk of the changes are mostly consequences of the changes
in API.
PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just
for easier to rebasing. I plan to rename it back after this lands.
Fixes#136624
Fixes https://github.com/llvm/llvm-project/issues/43179
Fixes https://github.com/llvm/llvm-project/issues/68670
Fixes https://github.com/llvm/llvm-project/issues/92757
To initialize all elements of a primitive array at once. This saves us
from creating the InitMap just to destroy it again after all elements
have been initialized.
As a way of writing atIndex(I).deref<T>(), which creates an intermediate
Pointer, which in turn adds (and removes) that pointer from the pointer
list of the Block. This way we can avoid that.
Static analysis flagged multiple places we could move instead of copy.
In one case I realized we could avoid computing the same thing multiple
times and did that fix instead.
…types usi… (#144676)"
This reverts commit 68471d29eed2c49f9b439e505b3f24d387d54f97.
IntegralAP contains a union:
union {
uint64_t *Memory = nullptr;
uint64_t Val;
};
On 64bit systems, both Memory and Val have the same size. However, on 32
bit system, Val is 64bit and Memory only 32bit. Which means the default
initializer for Memory will only zero half of Val. We fixed this by
zero-initializing Val explicitly in the IntegralAP(unsigned BitWidth)
constructor.
See also the discussion in
https://github.com/llvm/llvm-project/pull/144246
Both `APInt` and `APFloat` will heap-allocate memory themselves using
the system allocator when the size of their data exceeds 64 bits.
This is why clang has `APNumericStorage`, which allocates its memory
using an allocator (via `ASTContext`) instead. Calling `getValue()` on
an ast node like that will then create a new `APInt`/`APFloat` , which
will copy the data (in the `APFloat` case, we even copy it twice).
That's sad but whatever.
In the bytecode interpreter, we have a similar problem. Large integers
and floating-point values are placement-new allocated into the
`InterpStack` (or into the bytecode, which is a `vector<std::byte>`).
When we then later interrupt interpretation, we don't run the destructor
for all items on the stack, which means we leak the memory the
`APInt`/`APFloat` (which backs the `IntegralAP`/`Floating` the
interpreter uses).
Fix this by using an approach similar to the one used in the AST. Add an
allocator to `InterpState`, which is used for temporaries and local
values. Those values will be freed at the end of interpretation. For
global variables, we need to promote the values to global lifetime,
which we do via `InitGlobal` and `FinishInitGlobal` ops.
Interestingly, this results in a slight _improvement_ in compile times:
https://llvm-compile-time-tracker.com/compare.php?from=6bfcdda9b1ddf0900f82f7e30cb5e3253a791d50&to=88d1d899127b408f0fb0f385c2c58e6283195049&stat=instructions:u
(but don't ask me why).
Fixes https://github.com/llvm/llvm-project/issues/139012
Instead of just peek()ing the values when evaluating the builtins and
later classify()ing all the call args once again to remove them, just do
it while evaluating. This saves quite a bit of code.
A previous change to InterpBuiltin.cpp fixed an unused variable warning
by using [[maybe unused]] and (void).
The code actually serves no useful purpose in non-debug builds, so let's
not include it there.
For some builtins, we dont' need to do anything, but due to the cleanup
code being the same for all builtins, we still had to duplicate the
value on the stack. Remove that and get rid of all the unnecessary
pressure on the InterpStack.
