sdesmalen marked an inline comment as done.
sdesmalen added a comment.
Thanks for having a look @SjoerdMeijer
================
Comment at: clang/utils/TableGen/SveEmitter.cpp:68
TypeSpec TS;
+ bool IsSplat;
bool Float, Signed, Immediate, Void, Constant, Pointer;
----------------
SjoerdMeijer wrote:
> I was wondering if IsSplat belongs here or somewhere else. It doesn't sound
> like a type, like the other members do, but more a specific case of a vector?
> But saying this off the top of my head, haven't looked at the code and the
> context, but perhaps you can comment on this if this is where it should be or
> not.
This is for type modifiers like `a` which is defined as:
a: scalar of element type (splat to vector type)
which is used in the definition of the `_n` forms of builtins like:
svuint16_t svadd_n_u16_z(svbool_t pg, svuint16_t op1, uint16_t op2)
Here `op2` is `uint16_t` instead of `svuint16_t`. This operand is conceptually
splat to a SVE vector for the operation (that is what the instruction will do).
This is also how we implement it in CGBuiltin, because there is only a LLVM IR
intrinsic for the (vector, vector) form. In CodeGen we may map the (vector,
vector) form back onto a (vector, imm) instruction if the value fits the
immediate.
Because it is part of the modifier, I thought it made sense to add that
information to SVEType so that `applyModifier` can set that property, avoiding
the very opaque `Proto.find_first_of("ajfrKLR")` in `hasSplat` to determine
this. Maybe it isn't strictly part of the type (although you can probably also
argue it kind of is), but in any case I thought might make the code a bit more
readable because now all such information can live in one place
(`applyModifier`).
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D78995/new/
https://reviews.llvm.org/D78995
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