search for: getelementcount

...true. It is now impossible to construct a base VectorType. Additionally, FixedVectorType::get and ScalableVectorType::get functions have been added that allow you to directly construct these types. I have also added an overload of VectorType::get that takes a type, and a vector. This overload calls getElementCount() on the given vector and uses that to construct a new VectorType. This is a convenience helper for the cases where "I want a vector with the same shape as this other vector, but a different element type." Calls to VectorType::get(SomeTy, SomeVTy->getNumElements()) that try to implemen...

...true. It is now impossible to construct a base VectorType. Additionally, FixedVectorType::get and ScalableVectorType::get functions have been added that allow you to directly construct these types. I have also added an overload of VectorType::get that takes a type, and a vector. This overload calls getElementCount() on the given vector and uses that to construct a new VectorType. This is a convenience helper for the cases where “I want a vector with the same shape as this other vector, but a different element type.” Calls to VectorType::get(SomeTy, SomeVTy->getNumElements()) that try to implement this cas...

...all of this work is undone. Every place that has been fixed up to correctly have VectorType be used as a universal vector type will now incorrectly have the fixed width vector type being used as the universal vector type. Since VectorType will inherit from BaseVectorType, it will have inherited the getElementCount(), so the compiler will happily continue to compile this code. However, none of this code will even work with scalable vectors because the bool will always be false. There will be no compile time indication that this is going on, functions will just start mysteriously returning nullptr. Earlier thi...

...s have been written <n x ty> in IR, where n is a fixed number of elements known at compile time, and ty is some type. Scalable vectors are written <vscale x n x ty> where vscale is a runtime constant value. A new function has been added to VectorType (defined in llvm/IR/DerivedTypes.h), getElementCount(), that returns an ElementCount, which is defined as such in llvm/Support/TypeSize.h: class ElementCount { public: unsigned Min; bool Scalable; ... } Min is the minimum number of elements in the vector (the "n" in <vscale x n x ty>), and Scalabl...

...code to handle scalable vectors correctly. If the call site does not have test coverage with scalable vectors, this test coverage is being added. Even for obviously correct transformations such as `VectorType::get(SomeTy, SomeVecTy->getNumElements())` -> `VectorType::get(SomeTy, SomeVecTy->getElementCount())`, I have been required in code review to provide test coverage. We are taking this seriously. > “Vector” has a traditional and dominant meaning as a fixed-width SIMD type, and the fact that you’ve introduced a generalization doesn’t change that. Clang supports multiple kinds of pointer, but...

...s have been written <n x ty> in IR, where n is a fixed number of elements known at compile time, and ty is some type. Scalable vectors are written <vscale x n x ty> where vscale is a runtime constant value. A new function has been added to VectorType (defined in llvm/IR/DerivedTypes.h), getElementCount(), that returns an ElementCount, which is defined as such in llvm/Support/TypeSize.h: class ElementCount { public: unsigned Min; bool Scalable; ... } Min is the minimum number of elements in the vector (the "n" in <vscale x n x ty>), and Scalable is true if the vector is scalable (t...

...-scalable vectors (``Scalable=false``) the scale is considered to be equal to one and thus `Min` represents the exact number of elements in the vector. The intent for code working with vectors is to use convenience methods and avoid directly dealing with the number of elements. If needed, calling `getElementCount` on a vector type instead of `getVectorNumElements` can be used to obtain the (potentially scalable) number of elements. Overloaded division and multiplication operators allow an ElementCount instance to be used in much the same manner as an integer for most cases. This mixture of static and runti...

...ntCount and VectorType type hierarchy: ------------------------------------------- To represent the number of elements in a vector, the class ElementCount is used to describe N lanes of a fixed-width vector or vscale * N lanes of a scalable vector. Initially, we added the `ElementCount VectorType::getElementCount()` interface alongside `unsigned VectorType::getNumElements()`. In March this year, Christopher Tetreault took on the monumental task to distinguish vector types in the codebase by modifying the type hierarchy for VectorType (http://lists.llvm.org/pipermail/llvm-dev/2020-March/139811.html). Chris...

Bringing this up on llvm-dev for more general attention. The problem here is two fold: (1) Reuse of enumeration values is just a major no-go. (2) I'm not sure why the existing vector types had to be killed completely. But something clearly has to be done here. This majorly affects e.g. Mesa. Joerg ----- Forwarded message from Joerg Sonnenberger via llvm-commits <llvm-commits at

...-scalable vectors (``Scalable=false``) the scale is considered to be equal to one and thus `Min` represents the exact number of elements in the vector. The intent for code working with vectors is to use convenience methods and avoid directly dealing with the number of elements. If needed, calling `getElementCount` on a vector type instead of `getVectorNumElements` can be used to obtain the (potentially scalable) number of elements. Overloaded division and multiplication operators allow an ElementCount instance to be used in much the same manner as an integer for most cases. This mixture of compile-time and...

...nsidered to be >> equal to one and thus `Min` represents the exact number of elements in the >> vector. >> >> The intent for code working with vectors is to use convenience methods and avoid >> directly dealing with the number of elements. If needed, calling >> `getElementCount` on a vector type instead of `getVectorNumElements` can be used >> to obtain the (potentially scalable) number of elements. Overloaded division and >> multiplication operators allow an ElementCount instance to be used in much the >> same manner as an integer for most cases. >...

...=false``) the scale is considered to be > equal to one and thus `Min` represents the exact number of elements in the > vector. > > The intent for code working with vectors is to use convenience methods and avoid > directly dealing with the number of elements. If needed, calling > `getElementCount` on a vector type instead of `getVectorNumElements` can be used > to obtain the (potentially scalable) number of elements. Overloaded division and > multiplication operators allow an ElementCount instance to be used in much the > same manner as an integer for most cases. > > This mix...

...false``) the scale is considered to be > equal to one and thus `Min` represents the exact number of elements in the > vector. > > The intent for code working with vectors is to use convenience methods and avoid > directly dealing with the number of elements. If needed, calling > `getElementCount` on a vector type instead of `getVectorNumElements` can be used > to obtain the (potentially scalable) number of elements. Overloaded division and > multiplication operators allow an ElementCount instance to be used in much the > same manner as an integer for most cases. > > This mi...

...-scalable vectors (``Scalable=false``) the scale is considered to be equal to one and thus `Min` represents the exact number of elements in the vector. The intent for code working with vectors is to use convenience methods and avoid directly dealing with the number of elements. If needed, calling `getElementCount` on a vector type instead of `getVectorNumElements` can be used to obtain the (potentially scalable) number of elements. Overloaded division and multiplication operators allow an ElementCount instance to be used in much the same manner as an integer for most cases. This mixture of compile-time and...

...-scalable vectors (``Scalable=false``) the scale is considered to be equal to one and thus `Min` represents the exact number of elements in the vector. The intent for code working with vectors is to use convenience methods and avoid directly dealing with the number of elements. If needed, calling `getElementCount` on a vector type instead of `getVectorNumElements` can be used to obtain the (potentially scalable) number of elements. Overloaded division and multiplication operators allow an ElementCount instance to be used in much the same manner as an integer for most cases. This mixture of compile-time and...

...-scalable vectors (``Scalable=false``) the scale is considered to be equal to one and thus `Min` represents the exact number of elements in the vector. The intent for code working with vectors is to use convenience methods and avoid directly dealing with the number of elements. If needed, calling `getElementCount` on a vector type instead of `getVectorNumElements` can be used to obtain the (potentially scalable) number of elements. Overloaded division and multiplication operators allow an ElementCount instance to be used in much the same manner as an integer for most cases. This mixture of compile-time and...

...=false``) the scale is considered to be > equal to one and thus `Min` represents the exact number of elements in the > vector. > > The intent for code working with vectors is to use convenience methods and avoid > directly dealing with the number of elements. If needed, calling > `getElementCount` on a vector type instead of `getVectorNumElements` can be used > to obtain the (potentially scalable) number of elements. Overloaded division and > multiplication operators allow an ElementCount instance to be used in much the > same manner as an integer for most cases. > > This mix...

...hus `Min` represents the exact number of > elements in the > > vector. > > > > The intent for code working with vectors is to use convenience > methods and avoid > > directly dealing with the number of elements. If needed, calling > > `getElementCount` on a vector type instead of > `getVectorNumElements` can be used > > to obtain the (potentially scalable) number of elements. > Overloaded division and > > multiplication operators allow an ElementCount instance to be > used in much the > > same m...

...=false``) the scale is considered to be > equal to one and thus `Min` represents the exact number of elements in the > vector. > > The intent for code working with vectors is to use convenience methods and avoid > directly dealing with the number of elements. If needed, calling > `getElementCount` on a vector type instead of `getVectorNumElements` can be used > to obtain the (potentially scalable) number of elements. Overloaded division and > multiplication operators allow an ElementCount instance to be used in much the > same manner as an integer for most cases. > > This mix...

...between different scalable vector types without knowing their exact length. ## IR Interface: ```cpp static VectorType *get(Type *ELType, ElementCount EC); // Legacy interface whilst code is migrated. static VectorType *get(Type *ElType, unsigned NumEls, bool Scalable=false); ElementCount getElementCount(); bool isScalable(); ``` ## IR Textual Form: The textual IR for vectors becomes: `<[n x] <m> x <type>>` where `type` is the scalar type of each element, `m` corresponds to `Min` and the optional string literal `n x ` signifies `Scalable` is *true* when present, false otherw...