[all-commits] [llvm/llvm-project] de65b6: [Clang] Add __builtin_vectorelements to get number...

[Lawrence Benson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: de65b6bec6771fe50f3aa73fdb79594f675be456
      https://github.com/llvm/llvm-project/commit/de65b6bec6771fe50f3aa73fdb79594f675be456
  Author: Lawrence Benson <github at lawben.com>
  Date:   2023-10-19 (Thu, 19 Oct 2023)

  Changed paths:
    M clang/docs/LanguageExtensions.rst
    M clang/docs/ReleaseNotes.rst
    M clang/include/clang/AST/Type.h
    M clang/include/clang/Basic/Builtins.def
    M clang/include/clang/Basic/DiagnosticASTKinds.td
    M clang/include/clang/Basic/DiagnosticSemaKinds.td
    M clang/include/clang/Basic/TokenKinds.def
    M clang/lib/AST/ExprConstant.cpp
    M clang/lib/AST/ItaniumMangle.cpp
    M clang/lib/AST/Type.cpp
    M clang/lib/CodeGen/CGExprScalar.cpp
    M clang/lib/Parse/ParseExpr.cpp
    M clang/lib/Sema/SemaChecking.cpp
    M clang/lib/Sema/SemaExpr.cpp
    A clang/test/CodeGen/builtin_vectorelements.c
    A clang/test/Sema/builtin_vectorelements.c
    M clang/test/Sema/convertvector.c
    A clang/test/SemaCXX/builtin_vectorelements.cpp

  Log Message:
  -----------
  [Clang] Add __builtin_vectorelements to get number of elements in vector (#69010)

Adds a new `__builtin_vectorelements()` function which returns the
number of elements for a given vector either at compile-time for
fixed-sized vectors, e.g., created via `__attribute__((vector_size(N)))`
or at runtime via a call to `@llvm.vscale.i32()` for scalable vectors,
e.g., SVE or RISCV V.

The new builtin follows a similar path as `sizeof()`, as it essentially
does the same thing but for the number of elements in vector instead of
the number of bytes. This allows us to re-use a lot of the existing
logic to handle types etc.

A small side addition is `Type::isSizelessVectorType()`, which we need
to distinguish between sizeless vectors (SVE, RISCV V) and sizeless
types (WASM).

This is the [corresponding
discussion](https://discourse.llvm.org/t/new-builtin-function-to-get-number-of-lanes-in-simd-vectors/73911).