Simon Tatham e9d4f961f1 [ARM] Set up infrastructure for MVE vector instructions. ... This commit prepares the way to start adding the main collection of MVE instructions, which operate on the 128-bit vector registers. The most obvious thing that's needed, and the simplest, is to add the MQPR register class, which is like the existing QPR except that it has fewer registers in it. The more complicated part: MVE defines a system of vector predication, in which instructions operating on 128-bit vector registers can be constrained to operate on only a subset of the lanes, using a system of prefix instructions similar to the existing Thumb IT, in that you have one prefix instruction which designates up to 4 following instructions as subject to predication, and within that sequence, the predicate can be inverted by means of T/E suffixes ('Then' / 'Else'). To support instructions of this type, we've added two new Tablegen classes `vpred_n` and `vpred_r` for standard clusters of MC operands to add to a predicated instruction. Both include a flag indicating how the instruction is predicated at all (options are T, E and 'not predicated'), and an input register field for the register controlling the set of active lanes. They differ from each other in that `vpred_r` also includes an input operand for the previous value of the output register, for instructions that leave inactive lanes unchanged. `vpred_n` lacks that extra operand; it will be used for instructions that don't preserve inactive lanes in their output register (either because inactive lanes are zeroed, as the MVE load instructions do, or because the output register isn't a vector at all). This commit also adds the family of prefix instructions themselves (VPT / VPST), and all the machinery needed to work with them in assembly and disassembly (e.g. generating the 't' and 'e' mnemonic suffixes on disassembled instructions within a predicated block) I've added a couple of demo instructions that derive from the new Tablegen base classes and use those two operand clusters. The bulk of the vector instructions will come in followup commits small enough to be manageable. (One exception is that I've added the full version of `isMnemonicVPTPredicable` in the AsmParser, because it seemed pointless to carefully split it up.) Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover Subscribers: javed.absar, kristof.beyls, hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D62669 llvm-svn: 363258		2019-06-13 13:11:13 +00:00
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ARMBaseInfo.cpp
ARMBaseInfo.h
CMakeLists.txt
LLVMBuild.txt