107 Commits

Author SHA1 Message Date
Craig Topper
bc91f3cdd5
[RISCV] Add 32 bit GPR sub-register for Zfinx. (#108336)
This patches adds a 32 bit register class for use with Zfinx instructions. This makes them more similar to F instructions and allows us to only spill 32 bits.
    
I've added CodeGenOnly instructions for load/store using GPRF32 as that gave better results than insert_subreg/extract_subreg.
    
Function arguments use this new GPRF32 register class for f32 arguments with Zfinx. Eliminating the need to use RISCVISD::FMV* nodes.
    
This is similar to #107446 which adds a 16 bit register class.
2024-10-01 22:09:27 -07:00
Craig Topper
8a7843ca0f
[RISCV] Add 16 bit GPR sub-register for Zhinx. (#107446)
This patches adds a 16 bit register class for use with Zhinx
instructions. This makes them more similar to Zfh instructions and
allows us to only spill 16 bits.

I've added CodeGenOnly instructions for load/store using GPRF16 as that
gave better results than insert_subreg/extract_subreg. I'm using FSGNJ
for GPRF16 copy with Zhinx as that gave better results. Zhinxmin will
use ADDI+subreg operations.

Function arguments use this new GPRF16 register class for f16 arguments
with Zhinxmin. Eliminating the need to use RISCVISD::FMV* nodes.

I plan to extend this idea to Zfinx next.
2024-09-26 22:56:12 -07:00
Craig Topper
5537ae87b3 [RISCV] Fix fneg.d/fabs.d aliasing handling for Zdinx. Add missing fmv.s/d aliases.
We were missing test coverage for fneg.d/fabs.d for Zdinx. When I
added it revealed it only worked on RV64. The assembler was not
creating a GPRPair register class on RV32 so the alias couldn't match.
The disassembler was also not using GPRPair registers preventing the
aliases from printing in disassembly too.

I've fixed the assembler by adding new parsing methods in an attempt
to get decent diagnostics. This is hard since the mnemonics are
ambiguous between D and Zdinx. Tests have been adjusted for some
differences in what errors are reported first.
2024-09-10 11:44:04 -07:00
R
3c5f929ad0
[RISCV] Add QingKe "XW" compressed opcode extension (#97925)
This extension consists of 8 additional 16-bit compressed forms for
existing standard load/store opcodes.

These opcodes are found in some RISC-V microcontrollers from WCH /
Nanjing Qinheng Microelectronics.

As discussed in the Discourse forums, this uses incompatible extension
and opcode names vs the vendor binary toolchain. The chosen names
instead follow the conventions for other vendor extensions listed on the
"riscv-non-isa" project.
2024-07-11 11:10:02 +08:00
Craig Topper
618adc762e
[RISCV] Support instruction sizes up to 176-bits in disassembler. (#90371)
We don't have any instructions defined yet, but that we can still read the correct number of bytes when disassembling. This should better match GNU objdump behavior.
2024-04-29 10:11:28 -07:00
Craig Topper
5569c219d3
[RISCV] Split RISCVDisassembler::getInstruction into a 16-bit and 32-bit version. (#90254)
This reduces nesting of the common 32-bit case and makes it easier to
add longer instruction lengths in the future.
2024-04-26 15:52:05 -07:00
Craig Topper
5dd46d93fb [RISCV] Fix off by 1 typo in decodeVMaskReg. NFC
We're decoding a 1 bit field, but checked that the value was <= 2
instead of <= 1.

This isn't a functional change because the generated disassembler code
that calls this only extracts 1 bit.
2024-04-26 12:10:24 -07:00
Craig Topper
ac45bb5cbc [RISCV] Consistently use uint32_t in Disassembler decode functions. NFC
We had some uses of uint64_t and unsigned. These all come from tblgen
code that is templated on InsnType which is currently uint32_t.
2024-04-26 11:58:20 -07:00
Craig Topper
016ce9ed5c
[RISCV] Rename FeatureRVE to FeatureStdExtE. NFC (#89174)
Planning to declare all extensions in tablegen so we can generate the
tables for RISCVISAInfo.cpp. This requires making "e" consistent with
other extensions.
2024-04-19 12:39:32 -07:00
Craig Topper
207e45fb67
[RISCV] Add back SiFive's cdiscard.d.l1, cflush.d.l1, and cease instructions. (#83896)
These were in LLVM 17 but removed from LLVM 18 due to an incorrect
extension name being used.

This restores them with new extension names that match SiFive's
downstream compiler. The extension name has been used internally for
some time. It uses XSiFive instead of XSf like the newer extensions.
`cease` did not have an internal extension name so its using the `XSf`
convention.

The spec for the instructions is here
https://sifive.cdn.prismic.io/sifive/767804da-53b2-4893-97d5-b7c030ae0a94_s76mc_core_complex_manual_21G3.pdf
though the extension name is not listed.

Column width in the extension printing had to be changed to accommodate
a longer extension name.
2024-03-13 14:56:25 -07:00
Yeting Kuo
0716d31649
[RISCV][NFC] Use maybe_unused instead of casting to void to fix unused variable warning. (#80651) 2024-02-06 14:41:47 +08:00
Craig Topper
c053e9f0f4
[RISCV] Re-implement Zacas MC layer support to make it usable for CodeGen. (#77418)
This changes the register class to GPRPair and adds the destination
register as a source with a tied operand constraint.
    
Parsing for the paired register is done with a custom parser that
checks for even register and converts it to its pair version. A
bit of care needs to be taken so that we only parse as a pair register
based on which instruction we're parsing and the mode in the subtarget.
This allows amocas.w to be parsed correcty in both modes.
    
I've added a FIXME to note that we should be creating pair registers
for Zdinx on RV32 to match the instructions CodeGen generates.
2024-01-10 09:18:40 -08:00
Craig Topper
c9da4dc77f
[RISCV] Refactor GPRF64 register class to make it usable for Zacas. (#77408)
-Rename to GPRPair.
-Rename registers to be named like X10_X11 instead of X10_PD. Except X0
 which is now X0_Pair since it is not paired with X1.
-Use unknown size and offset for the subreg indices. This might
 be a functional change, but does not affect any lit tests.
2024-01-09 09:21:27 -08:00
Yeting Kuo
3dc0638cfc
[RISCV] Add MC layer support for Zicfiss. (#66043)
The patch adds the instructions in Zicfiss extension. Zicfiss extension
is to support shadow stack for control flow integrity. This patch is
based on version [0.3.1].

[0.3.1]: https://github.com/riscv/riscv-cfi/releases/tag/v0.3.1
2023-12-30 15:40:20 +08:00
Craig Topper
6dc5ba4cca [RISCV] Remove XSfcie extension.
This reverts 0d3eee33f262402562a1ff28106dbb2f59031bdb and
4c37d30e22ae655394c8b3a7e292c06d393b9b44.

XSfcie is not an official SiFive extension name. It stands for
SiFive Custom Instruction Extension, which is mentioned in the S76
manual, but then elsewhere in the manual says it is not supported
for S76.

LLVM had various instructions and CSRs listed as part of this
extension, but as far as SiFive is concerned, none of them are part
of it. There are no documented extension names for these instructions
and CSRs either externally or internally.

If these are important to LLVM users, I can facilitate creating
extension names for them and have them documented. For now I'm
removing everything.

Unfortunately, these instructions and CSRs are in LLVM 17 so this
is an incompatible change.
2023-12-28 13:54:15 -08:00
Yeting Kuo
256bf56afa
[RISCV] Update DecoderMethod and MCOperandPredicate of spimm. (#76061)
he spimm operand is an immediate whose only 4-5th bit could be setted
and not based on rlist operand
2023-12-27 09:11:34 +08:00
LiaoChunyu
71a7108ee9 [RISCV][MC] MC layer support for xcvmem and xcvelw extensions
This commit is part of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.
Several other extensions have been merged.
Spec:
https://github.com/openhwgroup/cv32e40p/blob/master/docs/source/instruction_set_extensions.rst
Contributors: @CharKeaney, @jeremybennett, @lewis-revill, Nandni Jamnadas, @PaoloS, @simoncook, @xmj, @realqhc, @melonedo, @adeelahmad81299

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D158824
2023-11-16 09:46:11 +08:00
Brandon Wu
74f38df1d1
[RISCV] Support Xsfvfnrclipxfqf extensions (#68297)
FP32-to-int8 Ranged Clip Instructions

https://sifive.cdn.prismic.io/sifive/0aacff47-f530-43dc-8446-5caa2260ece0_xsfvfnrclipxfqf-spec.pdf
2023-11-03 10:52:37 +08:00
Brandon Wu
945d2e6e60
[RISCV] Support Xsfvfwmaccqqq extensions (#68296)
Bfloat16 Matrix Multiply Accumulate Instruction

https://sifive.cdn.prismic.io/sifive/c391d53e-ffcf-4091-82f6-c37bf3e883ed_xsfvfwmaccqqq-spec.pdf
2023-11-03 10:08:26 +08:00
flyingcat
e6971e5a41
[RISCV][NFC] Simplify vector register decoding methods (#70423)
Combine redundant 'if' statements and simplify 'switch' statements.
2023-10-31 10:01:07 +08:00
Brandon Wu
d1985e3d1f
[RISCV] Support Xsfvqmaccdod and Xsfvqmaccqoq extensions (#68295)
SiFive Int8 Matrix Multiplication Extensions Specification

https://sifive.cdn.prismic.io/sifive/c4f0e51d-4dd3-402a-98bc-1ffad6011259_int8-matmul-spec.pdf
2023-10-20 11:16:20 +08:00
Jim Lin
f3c0eaeb2e [RISCV] Rename Ventana DecoderNamespace to XVentana for matching other extension. NFC.
All of them have prefix 'X' in DecoderNamespace.
2023-08-19 12:44:59 +08:00
Craig Topper
b4bb111b80 [RISCV] Rename XTHead DecoderNamespaces to match their extension names include the 'X'. NFC
This is consistent with other vendor extensions.
2023-07-30 12:09:03 -07:00
Craig Topper
0c7d897627 [RISCV] Rename DecoderNamespace for XCVsimd to be consistent with other XCV extensions. NFC 2023-07-30 12:00:46 -07:00
melonedo
afb9c04a5a [RISCV] Add support for XCVbi extension in CV32E40P
Implement XCVbi intrinsics for CV32E40P according to the specification.

This commit is part of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.

Contributors: @CharKeaney, @jeremybennett, @lewis-revill, @liaolucy, Nandni Jamnadas, @paolos, @simoncook, @xmj.

bf2ad26b4ff856aab9a62ad168e6bdefeedc374f originally commited.
e4777dc4b9cb371971523cc603e1b8a5c7255e7e reverted due to test failures caused by a merge conflict marker in llvm/test/CodeGen/RISCV/attributes that was accidentally checked in.
This commit removed the conflict marker and recommitted.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D154412
2023-07-28 21:54:10 +08:00
melonedo
e4777dc4b9 Revert "[RISCV] Add support for XCVbi extension in CV32E40P"
This reverts commit bf2ad26b4ff856aab9a62ad168e6bdefeedc374f as it
checked in merge conflict markers.
2023-07-28 19:28:20 +08:00
melonedo
bf2ad26b4f [RISCV] Add support for XCVbi extension in CV32E40P
Implement XCVbi intrinsics for CV32E40P according to the specification.

This commit is part of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.

Contributors: @CharKeaney, @jeremybennett, @lewis-revill, @liaolucy, Nandni Jamnadas, @PaoloS, @simoncook, @xmj.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D154412
2023-07-28 17:36:57 +08:00
melonedo
3c0604b224 [RISCV] Add support for XCVsimd extension in CV32E40P
Implement XCVsimd intrinsics for CV32E40P according to the specification.

This commit is part of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.

Contributors: @CharKeaney, @jeremybennett, @lewis-revill, @liaolucy, Nandni Jamnadas, @PaoloS, @simoncook, @xmj.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D153721
2023-07-28 16:52:32 +08:00
Qihan Cai
092e60a3fc [RISCV] Add support for XCValu extension in CV32E40P
Implement XCValu intrinsics for CV32E40P according to the specification.

This is a commit of the patch-set to upstream the 7 vendor specific extensions of CV32E40P.

Contributors: @CharKeaney, Nandni Jamnadas, Serkan Muhcu, @jeremybennett, @lewis-revill, @liaolucy, @simoncook, @xmj

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D153748
2023-07-28 11:37:31 +08:00
Garvit Gupta
4c37d30e22 [RISCV] Add support for custom instructions for Sifive S76.
Support for below instruction is added
1. CFLUSH.D.L1
2. CDISCARD.D.L1
3. CEASE

Additionally, Zihintpause extension is added to sifive s76 for pause
instruction.

Spec - https://sifive.cdn.prismic.io/sifive/767804da-53b2-4893-97d5-b7c030ae0a94_s76mc_core_complex_manual_21G3.pdf

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D153370
2023-06-26 11:36:00 -07:00
Qihan Cai
e219dd88d1 [RISCV] Add support for XCVmac extension in CV32E40P
Implement XCVmac intrinsics for CV32E40P according to the specification.

This is the first commit of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.

The patch-set aims at upstreaming the extensions on MC. The following will be on CodeGen, and the final patch-set will be on builtins if possible. The implemented version is on [0].

Contributors: @CharKeaney, Serkan Muhcu, @jeremybennett, @lewis-revill, @liaolucy, @simoncook, @xmj

Spec: 62bec66b36/docs/source/instruction_set_extensions.rst

[0] https://github.com/openhwgroup/corev-llvm-project

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D152821
2023-06-21 23:08:49 +08:00
melonedo
c5a412dad5 [RISCV] Add support for XCVbitmanip extension in CV32E40P
Implement XCVbitmanip intrinsics for CV32E40P according to the specification.

This commit is part of a patch-set to upstream the 7 vendor specific extensions of CV32E40P.

Contributors: @CharKeaney, @jeremybennett, @lewis-revill, @liaolucy, @simoncook, @xmj.

Spec: 62bec66b36/docs/source/instruction_set_extensions.rst

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D152915
2023-06-19 21:16:07 +08:00
wangpc
92723d5a32 [RISCV][NFC] Simplify decoding code of disassembler
The decoding parts are reduplicative, we add a macro to simplify
the code.

Reviewed By: craig.topper, kito-cheng

Differential Revision: https://reviews.llvm.org/D151309
2023-05-25 15:24:41 +08:00
Craig Topper
8f43c3f49e [RISCV] Rework how implied SP operands work in the disassembler. NFC
Previously we added the SP operands when an immediate operand was added
to certain opcodes.

This patch moves it to a post processing step using the information
in MCInstrDesc. This avoids an explicit opcode list in RISCVDisassembler.cpp.

In considered using a custom DecoderMethod, but the bit swizzling we
need to do for the immediates on these instructions made that
unattractive.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D149931
2023-05-16 09:43:38 -07:00
WuXinlong
6b55e9117e [RISCV] Add MC support of RISCV zcmp Extension
This patch add the instructions of zcmp extension.

Instructions in zcmp extension try to optimise `mv` inst and the prologue & epilogue in functions

co-author: @Scott Egerton, @ZirconLiu, @Lukacma, @Heda Chen, @luxufan, @heyiliang, @liaochunyu

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D132819
2023-05-08 14:29:50 +08:00
Craig Topper
7b3b178c82 [RISCV] Add DecoderNamespace to Zcmt instructions.
The Zcmt instructions overlap encoding space with some C extension
instructions. Isolate to a separate namespace.

Reviewed By: VincentWu

Differential Revision: https://reviews.llvm.org/D149891
2023-05-05 10:08:43 -07:00
Craig Topper
d421c5f81a [RISCV] Directly create MCOperands from addImplySP in Disassembler. NFC
Instead of passing a constant to DecodeGPRRegisterClass, just create
the X2 register directly.
2023-05-04 22:18:33 -07:00
Nelson Chu
0b9a620b83 [RISCV] Support assembler and dis-assembler for VCIX extension.
Spec: https://sifive.cdn.prismic.io/sifive/c3829e36-8552-41f0-a841-79945784241b_vcix-spec-software.pdf

Differential Revision: https://reviews.llvm.org/D144530
2023-04-09 20:41:01 -07:00
Craig Topper
29463612d2 [RISCV] Replace RISCV -> RISC-V in comments. NFC
To be consistent with RISC-V branding guidelines
https://riscv.org/about/risc-v-branding-guidelines/
Think we should be using RISC-V where possible.

More patches will follow.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D146449
2023-03-27 09:50:17 -07:00
Job Noorman
c39dd7c1db [RISCV][MC] Add support for RV64E
Implement MC support for the recently ratified RV64E base instruction
set.

Differential Revision: https://reviews.llvm.org/D143570
2023-03-23 12:32:25 +00:00
Philipp Tomsich
f68f04d07c [RISCV] Add vendor-defined XTheadCondMov (conditional move) extension
The vendor-defined XTheadCondMov (somewhat related to the upcoming
Zicond and XVentanaCondOps) extension add conditional move
instructions with $rd being an input and an ouput instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=73442230966a22b3238b2074691a71d7b4ed914a

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D144681
2023-02-24 21:40:42 +01:00
Manolis Tsamis
7b79e8d455 [RISCV] Add vendor-defined XTheadFMemIdx (FP Indexed Memory Operations) extension
The vendor-defined XTHeadFMemIdx (no comparable standard extension exists
at the time of writing) extension adds indexed load/store instructions
for floating-point registers.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f511f80fa3fcaf6bcbe727fb902b8bd5ec8f9c20

Depends on D144249

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D144647
2023-02-24 00:35:37 +01:00
Manolis Tsamis
f6262201d8 [RISCV] Add vendor-defined XTheadMemIdx (Indexed Memory Operations) extension
The vendor-defined XTHeadMemIdx (no comparable standard extension exists
at the time of writing) extension adds indexed load/store instructions
as well as load/store and update register instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=27cfd142d0a7e378d19aa9a1278e2137f849b71b

Depends on D144002

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D144249
2023-02-24 00:17:58 +01:00
Manolis Tsamis
16a6cf6a99 [RISCV] Add vendor-defined XTheadSync (Multi-core synchronization) extension
The vendor-defined XTheadSync (no comparable standard extension exists
at the time of writing) extension adds multi-core synchronization
instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=547c18d9bb95571261dbd17f4767194037eb82bd

Depends on D144496

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D144501
2023-02-22 11:15:40 +01:00
Manolis Tsamis
f5b484c56f [RISCV] Add vendor-defined XTheadCmo (Cache Management Operations) extension
The vendor-defined XTHeadCmo (there are some similarities with the
Zicbom standard extension) extension adds cache management instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a9ba8bc2d396fb8ae2b892f3bc6be8cdfe4b555c

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D144496
2023-02-22 10:57:48 +01:00
Manolis Tsamis
bbb58a2302 [RISCV] Add vendor-defined XTheadMemPair (two-GPR Memory Operations) extension
The vendor-defined XTHeadMemPair (no comparable standard extension exists
at the time of writing) extension adds two-GPR load/store pair instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=6e17ae625570ff8f3c12c8765b8d45d4db8694bd

Depends on D143847

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D144002
2023-02-21 12:21:49 +01:00
Craig Topper
34aff47521 [RISCV] Use MCSubtargetInfo::hasFeature where possible. NFC
Rather than using operator[] on getFeatureBits we can use
hasFeature to shorten the code.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D144300
2023-02-17 14:36:48 -08:00
Philipp Tomsich
16a66af0a0 Revert "[RISCV] Add vendor-defined XTheadMemPair (two-GPR Memory Operations) extension"
This reverts commit d2918544a7fc4b5443879fe12f32a712e6dfe325.
2023-02-17 19:45:55 +01:00
Manolis Tsamis
d2918544a7 [RISCV] Add vendor-defined XTheadMemPair (two-GPR Memory Operations) extension
The vendor-defined XTHeadMemPair (no comparable standard extension exists
at the time of writing) extension adds two-GPR load/store pair instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=6e17ae625570ff8f3c12c8765b8d45d4db8694bd

Depends on D143847

Differential Revision: https://reviews.llvm.org/D144002
2023-02-17 19:45:22 +01:00
Manolis Tsamis
d4012bc43f [RISCV] Add vendor-defined XTheadMAC (multiply-accumulate) extension
The vendor-defined XTHeadMAC (no comparable standard extension exists
at the time of writing) extension adds multiply accumulate instructions.

It is supported by the C9xx cores (e.g., found in the wild in the
Allwinner D1) by Alibaba T-Head.

The current (as of this commit) public documentation for this
extension is available at:
  https://github.com/T-head-Semi/thead-extension-spec/releases/download/2.2.2/xthead-2023-01-30-2.2.2.pdf

Support for these instructions has already landed in GNU Binutils:
  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=4041e11db3ec3611921d10150572a92689aa3154

Co-authored-by: Philipp Tomsich <philipp.tomsich@vrull.eu>

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D143847
2023-02-14 20:25:47 +01:00