[PATCH] D142348: [RISCV][Docs] Document code generation for vector extension

[Luke Lau via Phabricator via llvm-commits]

luke added inline comments.


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Comment at: llvm/docs/RISCV/RISCVVectorExtension.rst:185
+
+One downside of this design is that doesn’t allow vectors of i128 (this is, ELEN=128). In that case vscale would have to be 1/2 under :math:`\text{LMUL}=1`. This type (and its fp counterpart float128) are not that common and in case of extreme necessity types for :math:`\text{LMUL}=2` could be used instead.
+
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craig.topper wrote:
> This mapping also prevents the value of vscale from being examined if ELEN and VLEN are both 32.
I'm not sure if I understand, could you clarified by what you mean by examined? Is it related to https://reviews.llvm.org/D128286


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Comment at: llvm/docs/RISCV/RISCVVectorExtension.rst:293
+To assist with this, an intermediate layer of nodes that take an explicit ``VL`` operand is used.
+The nodes and their patterns are defined in ``RISCVInstrInfoVVLPatterns.td``.
+
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craig.topper wrote:
> This file is also used VP intrinsics for scalable vectors.
This is mentioned in the vector predication section below


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