[llvm-commits] [PATCH] Allow targets to prefer vector splitting over integer promotion

[Justin Holewinski]

The attached patch adds a new back-end hook that allows targets to prefer
vector splitting over integer promotion for type legalization.  Right now,
TargetLowering::computeRegisterProperties() will first try to promote <N x
iM> to <N x iP> where P > M if <N x iM> is illegal.  However, for some
targets, it is desirable to instead prefer splitting the vector.

The in-tree use case is the NVPTX back-end.  <N x i1> is not a legal type,
but promotion to <N x i8> or <N x i32> is not desirable.  Instead, we want
to force scalarization of vector code using these types (e.g. vselect).

-- 

Thanks,

Justin Holewinski
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