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path: root/llvm/lib/Target/RISCV/Utils/RISCVMatInt.cpp
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* [RISCV] Avoid signed integer overflow UB in RISCVMatInt::generateInstSeqAlex Bradbury2019-07-181-1/+1
| | | | | | Found by UBSan. llvm-svn: 366398
* [RISCV] Prevent re-ordering some adds after shiftsSam Elliott2019-06-181-4/+19
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: DAGCombine will normally turn a `(shl (add x, c1), c2)` into `(add (shl x, c2), c1 << c2)`, where `c1` and `c2` are constants. This can be prevented by a callback in TargetLowering. On RISC-V, materialising the constant `c1 << c2` can be more expensive than materialising `c1`, because materialising the former may take more instructions, and may use a register, where materialising the latter would not. This patch implements the hook in RISCVTargetLowering to prevent this transform, in the cases where: - `c1` fits into the immediate field in an `addi` instruction. - `c1` takes fewer instructions to materialise than `c1 << c2`. In future, DAGCombine could do the check to see whether `c1` fits into an add immediate, which might simplify more targets hooks than just RISC-V. Reviewers: asb, luismarques, efriedma Reviewed By: asb Subscribers: xbolva00, lebedev.ri, craig.topper, lewis-revill, Jim, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, PkmX, jocewei, psnobl, benna, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D62857 llvm-svn: 363736
* Update the file headers across all of the LLVM projects in the monorepoChandler Carruth2019-01-191-4/+3
| | | | | | | | | | | | | | | | | to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
* [RISCV] Introduce the RISCVMatInt::generateInstSeq helperAlex Bradbury2018-11-151-0/+79
Logic to load 32-bit and 64-bit immediates is currently present in RISCVAsmParser::emitLoadImm in order to support the li pseudoinstruction. With the introduction of RV64 codegen, there is a greater benefit of sharing immediate materialisation logic between the MC layer and codegen. The generateInstSeq helper allows this by producing a vector of simple structs representing the chosen instructions. This can then be consumed in the MC layer to produce MCInsts or at instruction selection time to produce appropriate SelectionDAG node. Sharing this logic means that both the li pseudoinstruction and codegen can benefit from future optimisations, and that this logic can be used for materialising constants during RV64 codegen. This patch does contain a behaviour change: addi will now be produced on RV64 when no lui is necessary to materialise the constant. In that case addiw takes x0 as the source register, so is semantically identical to addi. Differential Revision: https://reviews.llvm.org/D52961 llvm-svn: 346937
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