LLC-CLANG-MCU-CPU-TARGET.TXT

================================================================================
*** A handful of LLC/LLVM command-line flags are provided here for the
*** convenience to configure Tulu-C-IDE so that it can autocomplete
*** codes being written for different compiler backend targets and different
*** MCU/CPU units.
License: Boost Software License v1.0
Link to Tulu-C-IDE on GitHub:
https://github.com/Pinaki82/Tulu-C-IDE.git
================================================================================


https://stackoverflow.com/questions/15036909/clang-how-to-list-supported-target-architectures
llc -march=armeb -mattr=help
llc -march=arm -mattr=help
llc --version | grep Default
llc --version | grep armeb
llc --version | grep Default
llvm-config --host-target
clang -v 2>&1 | grep Target
clang-11 -print-targets
clang -print-targets
================================================================================

================================================================================
llc -march=armeb -mattr=help
Available CPUs for this target:

  arm1020e      - Select the arm1020e processor.
  arm1020t      - Select the arm1020t processor.
  arm1022e      - Select the arm1022e processor.
  arm10e        - Select the arm10e processor.
  arm10tdmi     - Select the arm10tdmi processor.
  arm1136j-s    - Select the arm1136j-s processor.
  arm1136jf-s   - Select the arm1136jf-s processor.
  arm1156t2-s   - Select the arm1156t2-s processor.
  arm1156t2f-s  - Select the arm1156t2f-s processor.
  arm1176j-s    - Select the arm1176j-s processor.
  arm1176jz-s   - Select the arm1176jz-s processor.
  arm1176jzf-s  - Select the arm1176jzf-s processor.
  arm710t       - Select the arm710t processor.
  arm720t       - Select the arm720t processor.
  arm7tdmi      - Select the arm7tdmi processor.
  arm7tdmi-s    - Select the arm7tdmi-s processor.
  arm8          - Select the arm8 processor.
  arm810        - Select the arm810 processor.
  arm9          - Select the arm9 processor.
  arm920        - Select the arm920 processor.
  arm920t       - Select the arm920t processor.
  arm922t       - Select the arm922t processor.
  arm926ej-s    - Select the arm926ej-s processor.
  arm940t       - Select the arm940t processor.
  arm946e-s     - Select the arm946e-s processor.
  arm966e-s     - Select the arm966e-s processor.
  arm968e-s     - Select the arm968e-s processor.
  arm9e         - Select the arm9e processor.
  arm9tdmi      - Select the arm9tdmi processor.
  cortex-a12    - Select the cortex-a12 processor.
  cortex-a15    - Select the cortex-a15 processor.
  cortex-a17    - Select the cortex-a17 processor.
  cortex-a32    - Select the cortex-a32 processor.
  cortex-a35    - Select the cortex-a35 processor.
  cortex-a5     - Select the cortex-a5 processor.
  cortex-a53    - Select the cortex-a53 processor.
  cortex-a55    - Select the cortex-a55 processor.
  cortex-a57    - Select the cortex-a57 processor.
  cortex-a7     - Select the cortex-a7 processor.
  cortex-a72    - Select the cortex-a72 processor.
  cortex-a73    - Select the cortex-a73 processor.
  cortex-a75    - Select the cortex-a75 processor.
  cortex-a76    - Select the cortex-a76 processor.
  cortex-a76ae  - Select the cortex-a76ae processor.
  cortex-a77    - Select the cortex-a77 processor.
  cortex-a78    - Select the cortex-a78 processor.
  cortex-a8     - Select the cortex-a8 processor.
  cortex-a9     - Select the cortex-a9 processor.
  cortex-m0     - Select the cortex-m0 processor.
  cortex-m0plus - Select the cortex-m0plus processor.
  cortex-m1     - Select the cortex-m1 processor.
  cortex-m23    - Select the cortex-m23 processor.
  cortex-m3     - Select the cortex-m3 processor.
  cortex-m33    - Select the cortex-m33 processor.
  cortex-m35p   - Select the cortex-m35p processor.
  cortex-m4     - Select the cortex-m4 processor.
  cortex-m55    - Select the cortex-m55 processor.
  cortex-m7     - Select the cortex-m7 processor.
  cortex-r4     - Select the cortex-r4 processor.
  cortex-r4f    - Select the cortex-r4f processor.
  cortex-r5     - Select the cortex-r5 processor.
  cortex-r52    - Select the cortex-r52 processor.
  cortex-r7     - Select the cortex-r7 processor.
  cortex-r8     - Select the cortex-r8 processor.
  cortex-x1     - Select the cortex-x1 processor.
  cyclone       - Select the cyclone processor.
  ep9312        - Select the ep9312 processor.
  exynos-m3     - Select the exynos-m3 processor.
  exynos-m4     - Select the exynos-m4 processor.
  exynos-m5     - Select the exynos-m5 processor.
  generic       - Select the generic processor.
  iwmmxt        - Select the iwmmxt processor.
  krait         - Select the krait processor.
  kryo          - Select the kryo processor.
  mpcore        - Select the mpcore processor.
  mpcorenovfp   - Select the mpcorenovfp processor.
  neoverse-n1   - Select the neoverse-n1 processor.
  sc000         - Select the sc000 processor.
  sc300         - Select the sc300 processor.
  strongarm     - Select the strongarm processor.
  strongarm110  - Select the strongarm110 processor.
  strongarm1100 - Select the strongarm1100 processor.
  strongarm1110 - Select the strongarm1110 processor.
  swift         - Select the swift processor.
  xscale        - Select the xscale processor.

Available features for this target:

  32bit                    - Prefer 32-bit Thumb instrs.
  8msecext                 - Enable support for ARMv8-M Security Extensions.
  a12                      - Cortex-A12 ARM processors.
  a15                      - Cortex-A15 ARM processors.
  a17                      - Cortex-A17 ARM processors.
  a32                      - Cortex-A32 ARM processors.
  a35                      - Cortex-A35 ARM processors.
  a5                       - Cortex-A5 ARM processors.
  a53                      - Cortex-A53 ARM processors.
  a55                      - Cortex-A55 ARM processors.
  a57                      - Cortex-A57 ARM processors.
  a7                       - Cortex-A7 ARM processors.
  a72                      - Cortex-A72 ARM processors.
  a73                      - Cortex-A73 ARM processors.
  a75                      - Cortex-A75 ARM processors.
  a76                      - Cortex-A76 ARM processors.
  a77                      - Cortex-A77 ARM processors.
  a8                       - Cortex-A8 ARM processors.
  a9                       - Cortex-A9 ARM processors.
  aclass                   - Is application profile ('A' series).
  acquire-release          - Has v8 acquire/release (lda/ldaex  etc) instructions.
  aes                      - Enable AES support.
  armv2                    - ARMv2 architecture.
  armv2a                   - ARMv2a architecture.
  armv3                    - ARMv3 architecture.
  armv3m                   - ARMv3m architecture.
  armv4                    - ARMv4 architecture.
  armv4t                   - ARMv4t architecture.
  armv5t                   - ARMv5t architecture.
  armv5te                  - ARMv5te architecture.
  armv5tej                 - ARMv5tej architecture.
  armv6                    - ARMv6 architecture.
  armv6-m                  - ARMv6m architecture.
  armv6j                   - ARMv7a architecture.
  armv6k                   - ARMv6k architecture.
  armv6kz                  - ARMv6kz architecture.
  armv6s-m                 - ARMv6sm architecture.
  armv6t2                  - ARMv6t2 architecture.
  armv7-a                  - ARMv7a architecture.
  armv7-m                  - ARMv7m architecture.
  armv7-r                  - ARMv7r architecture.
  armv7e-m                 - ARMv7em architecture.
  armv7k                   - ARMv7a architecture.
  armv7s                   - ARMv7a architecture.
  armv7ve                  - ARMv7ve architecture.
  armv8-a                  - ARMv8a architecture.
  armv8-m.base             - ARMv8mBaseline architecture.
  armv8-m.main             - ARMv8mMainline architecture.
  armv8-r                  - ARMv8r architecture.
  armv8.1-a                - ARMv81a architecture.
  armv8.1-m.main           - ARMv81mMainline architecture.
  armv8.2-a                - ARMv82a architecture.
  armv8.3-a                - ARMv83a architecture.
  armv8.4-a                - ARMv84a architecture.
  armv8.5-a                - ARMv85a architecture.
  armv8.6-a                - ARMv86a architecture.
  avoid-movs-shop          - Avoid movs instructions with shifter operand.
  avoid-partial-cpsr       - Avoid CPSR partial update for OOO execution.
  bf16                     - Enable support for BFloat16 instructions.
  cde                      - Support CDE instructions.
  cdecp0                   - Coprocessor 0 ISA is CDEv1.
  cdecp1                   - Coprocessor 1 ISA is CDEv1.
  cdecp2                   - Coprocessor 2 ISA is CDEv1.
  cdecp3                   - Coprocessor 3 ISA is CDEv1.
  cdecp4                   - Coprocessor 4 ISA is CDEv1.
  cdecp5                   - Coprocessor 5 ISA is CDEv1.
  cdecp6                   - Coprocessor 6 ISA is CDEv1.
  cdecp7                   - Coprocessor 7 ISA is CDEv1.
  cheap-predicable-cpsr    - Disable +1 predication cost for instructions updating CPSR.
  cortex-a78               - Cortex-A78 ARM processors.
  cortex-x1                - Cortex-X1 ARM processors.
  crc                      - Enable support for CRC instructions.
  crypto                   - Enable support for Cryptography extensions.
  d32                      - Extend FP to 32 double registers.
  db                       - Has data barrier (dmb/dsb) instructions.
  dfb                      - Has full data barrier (dfb) instruction.
  disable-postra-scheduler - Don't schedule again after register allocation.
  dont-widen-vmovs         - Don't widen VMOVS to VMOVD.
  dotprod                  - Enable support for dot product instructions.
  dsp                      - Supports DSP instructions in ARM and/or Thumb2.
  execute-only             - Enable the generation of execute only code..
  expand-fp-mlx            - Expand VFP/NEON MLA/MLS instructions.
  exynos                   - Samsung Exynos processors.
  fp-armv8                 - Enable ARMv8 FP.
  fp-armv8d16              - Enable ARMv8 FP with only 16 d-registers.
  fp-armv8d16sp            - Enable ARMv8 FP with only 16 d-registers and no double precision.
  fp-armv8sp               - Enable ARMv8 FP with no double precision.
  fp16                     - Enable half-precision floating point.
  fp16fml                  - Enable full half-precision floating point fml instructions.
  fp64                     - Floating point unit supports double precision.
  fpao                     - Enable fast computation of positive address offsets.
  fpregs                   - Enable FP registers.
  fpregs16                 - Enable 16-bit FP registers.
  fpregs64                 - Enable 64-bit FP registers.
  fullfp16                 - Enable full half-precision floating point.
  fuse-aes                 - CPU fuses AES crypto operations.
  fuse-literals            - CPU fuses literal generation operations.
  hwdiv                    - Enable divide instructions in Thumb.
  hwdiv-arm                - Enable divide instructions in ARM mode.
  i8mm                     - Enable Matrix Multiply Int8 Extension.
  iwmmxt                   - ARMv5te architecture.
  iwmmxt2                  - ARMv5te architecture.
  krait                    - Qualcomm Krait processors.
  kryo                     - Qualcomm Kryo processors.
  lob                      - Enable Low Overhead Branch extensions.
  long-calls               - Generate calls via indirect call instructions.
  loop-align               - Prefer 32-bit alignment for loops.
  m3                       - Cortex-M3 ARM processors.
  mclass                   - Is microcontroller profile ('M' series).
  mp                       - Supports Multiprocessing extension.
  muxed-units              - Has muxed AGU and NEON/FPU.
  mve                      - Support M-Class Vector Extension with integer ops.
  mve.fp                   - Support M-Class Vector Extension with integer and floating ops.
  mve1beat                 - Model MVE instructions as a 1 beat per tick architecture.
  mve2beat                 - Model MVE instructions as a 2 beats per tick architecture.
  mve4beat                 - Model MVE instructions as a 4 beats per tick architecture.
  nacl-trap                - NaCl trap.
  neon                     - Enable NEON instructions.
  neon-fpmovs              - Convert VMOVSR, VMOVRS, VMOVS to NEON.
  neonfp                   - Use NEON for single precision FP.
  no-branch-predictor      - Has no branch predictor.
  no-movt                  - Don't use movt/movw pairs for 32-bit imms.
  no-neg-immediates        - Convert immediates and instructions to their negated or complemented equivalent when the immediate does not fit in the encoding..
  noarm                    - Does not support ARM mode execution.
  nonpipelined-vfp         - VFP instructions are not pipelined.
  perfmon                  - Enable support for Performance Monitor extensions.
  prefer-ishst             - Prefer ISHST barriers.
  prefer-vmovsr            - Prefer VMOVSR.
  prof-unpr                - Is profitable to unpredicate.
  r4                       - Cortex-R4 ARM processors.
  r5                       - Cortex-R5 ARM processors.
  r52                      - Cortex-R52 ARM processors.
  r7                       - Cortex-R7 ARM processors.
  ras                      - Enable Reliability, Availability and Serviceability extensions.
  rclass                   - Is realtime profile ('R' series).
  read-tp-hard             - Reading thread pointer from register.
  reserve-r9               - Reserve R9, making it unavailable as GPR.
  ret-addr-stack           - Has return address stack.
  sb                       - Enable v8.5a Speculation Barrier.
  sha2                     - Enable SHA1 and SHA256 support.
  slow-fp-brcc             - FP compare + branch is slow.
  slow-load-D-subreg       - Loading into D subregs is slow.
  slow-odd-reg             - VLDM/VSTM starting with an odd register is slow.
  slow-vdup32              - Has slow VDUP32 - prefer VMOV.
  slow-vgetlni32           - Has slow VGETLNi32 - prefer VMOV.
  slowfpvfmx               - Disable VFP / NEON FMA instructions.
  slowfpvmlx               - Disable VFP / NEON MAC instructions.
  soft-float               - Use software floating point features..
  splat-vfp-neon           - Splat register from VFP to NEON.
  strict-align             - Disallow all unaligned memory access.
  swift                    - Swift ARM processors.
  thumb-mode               - Thumb mode.
  thumb2                   - Enable Thumb2 instructions.
  trustzone                - Enable support for TrustZone security extensions.
  use-misched              - Use the MachineScheduler.
  v4t                      - Support ARM v4T instructions.
  v5t                      - Support ARM v5T instructions.
  v5te                     - Support ARM v5TE, v5TEj, and v5TExp instructions.
  v6                       - Support ARM v6 instructions.
  v6k                      - Support ARM v6k instructions.
  v6m                      - Support ARM v6M instructions.
  v6t2                     - Support ARM v6t2 instructions.
  v7                       - Support ARM v7 instructions.
  v7clrex                  - Has v7 clrex instruction.
  v8                       - Support ARM v8 instructions.
  v8.1a                    - Support ARM v8.1a instructions.
  v8.1m.main               - Support ARM v8-1M Mainline instructions.
  v8.2a                    - Support ARM v8.2a instructions.
  v8.3a                    - Support ARM v8.3a instructions.
  v8.4a                    - Support ARM v8.4a instructions.
  v8.5a                    - Support ARM v8.5a instructions.
  v8.6a                    - Support ARM v8.6a instructions.
  v8m                      - Support ARM v8M Baseline instructions.
  v8m.main                 - Support ARM v8M Mainline instructions.
  vfp2                     - Enable VFP2 instructions.
  vfp2sp                   - Enable VFP2 instructions with no double precision.
  vfp3                     - Enable VFP3 instructions.
  vfp3d16                  - Enable VFP3 instructions with only 16 d-registers.
  vfp3d16sp                - Enable VFP3 instructions with only 16 d-registers and no double precision.
  vfp3sp                   - Enable VFP3 instructions with no double precision.
  vfp4                     - Enable VFP4 instructions.
  vfp4d16                  - Enable VFP4 instructions with only 16 d-registers.
  vfp4d16sp                - Enable VFP4 instructions with only 16 d-registers and no double precision.
  vfp4sp                   - Enable VFP4 instructions with no double precision.
  virtualization           - Supports Virtualization extension.
  vldn-align               - Check for VLDn unaligned access.
  vmlx-forwarding          - Has multiplier accumulator forwarding.
  vmlx-hazards             - Has VMLx hazards.
  wide-stride-vfp          - Use a wide stride when allocating VFP registers.
  xscale                   - ARMv5te architecture.
  zcz                      - Has zero-cycle zeroing instructions.

Use +feature to enable a feature, or -feature to disable it.
For example, llc -mcpu=mycpu -mattr=+feature1,-feature2


================================================================================
llc -march=arm -mattr=help
Available CPUs for this target:

  arm1020e      - Select the arm1020e processor.
  arm1020t      - Select the arm1020t processor.
  arm1022e      - Select the arm1022e processor.
  arm10e        - Select the arm10e processor.
  arm10tdmi     - Select the arm10tdmi processor.
  arm1136j-s    - Select the arm1136j-s processor.
  arm1136jf-s   - Select the arm1136jf-s processor.
  arm1156t2-s   - Select the arm1156t2-s processor.
  arm1156t2f-s  - Select the arm1156t2f-s processor.
  arm1176j-s    - Select the arm1176j-s processor.
  arm1176jz-s   - Select the arm1176jz-s processor.
  arm1176jzf-s  - Select the arm1176jzf-s processor.
  arm710t       - Select the arm710t processor.
  arm720t       - Select the arm720t processor.
  arm7tdmi      - Select the arm7tdmi processor.
  arm7tdmi-s    - Select the arm7tdmi-s processor.
  arm8          - Select the arm8 processor.
  arm810        - Select the arm810 processor.
  arm9          - Select the arm9 processor.
  arm920        - Select the arm920 processor.
  arm920t       - Select the arm920t processor.
  arm922t       - Select the arm922t processor.
  arm926ej-s    - Select the arm926ej-s processor.
  arm940t       - Select the arm940t processor.
  arm946e-s     - Select the arm946e-s processor.
  arm966e-s     - Select the arm966e-s processor.
  arm968e-s     - Select the arm968e-s processor.
  arm9e         - Select the arm9e processor.
  arm9tdmi      - Select the arm9tdmi processor.
  cortex-a12    - Select the cortex-a12 processor.
  cortex-a15    - Select the cortex-a15 processor.
  cortex-a17    - Select the cortex-a17 processor.
  cortex-a32    - Select the cortex-a32 processor.
  cortex-a35    - Select the cortex-a35 processor.
  cortex-a5     - Select the cortex-a5 processor.
  cortex-a53    - Select the cortex-a53 processor.
  cortex-a55    - Select the cortex-a55 processor.
  cortex-a57    - Select the cortex-a57 processor.
  cortex-a7     - Select the cortex-a7 processor.
  cortex-a72    - Select the cortex-a72 processor.
  cortex-a73    - Select the cortex-a73 processor.
  cortex-a75    - Select the cortex-a75 processor.
  cortex-a76    - Select the cortex-a76 processor.
  cortex-a76ae  - Select the cortex-a76ae processor.
  cortex-a77    - Select the cortex-a77 processor.
  cortex-a78    - Select the cortex-a78 processor.
  cortex-a8     - Select the cortex-a8 processor.
  cortex-a9     - Select the cortex-a9 processor.
  cortex-m0     - Select the cortex-m0 processor.
  cortex-m0plus - Select the cortex-m0plus processor.
  cortex-m1     - Select the cortex-m1 processor.
  cortex-m23    - Select the cortex-m23 processor.
  cortex-m3     - Select the cortex-m3 processor.
  cortex-m33    - Select the cortex-m33 processor.
  cortex-m35p   - Select the cortex-m35p processor.
  cortex-m4     - Select the cortex-m4 processor.
  cortex-m55    - Select the cortex-m55 processor.
  cortex-m7     - Select the cortex-m7 processor.
  cortex-r4     - Select the cortex-r4 processor.
  cortex-r4f    - Select the cortex-r4f processor.
  cortex-r5     - Select the cortex-r5 processor.
  cortex-r52    - Select the cortex-r52 processor.
  cortex-r7     - Select the cortex-r7 processor.
  cortex-r8     - Select the cortex-r8 processor.
  cortex-x1     - Select the cortex-x1 processor.
  cyclone       - Select the cyclone processor.
  ep9312        - Select the ep9312 processor.
  exynos-m3     - Select the exynos-m3 processor.
  exynos-m4     - Select the exynos-m4 processor.
  exynos-m5     - Select the exynos-m5 processor.
  generic       - Select the generic processor.
  iwmmxt        - Select the iwmmxt processor.
  krait         - Select the krait processor.
  kryo          - Select the kryo processor.
  mpcore        - Select the mpcore processor.
  mpcorenovfp   - Select the mpcorenovfp processor.
  neoverse-n1   - Select the neoverse-n1 processor.
  sc000         - Select the sc000 processor.
  sc300         - Select the sc300 processor.
  strongarm     - Select the strongarm processor.
  strongarm110  - Select the strongarm110 processor.
  strongarm1100 - Select the strongarm1100 processor.
  strongarm1110 - Select the strongarm1110 processor.
  swift         - Select the swift processor.
  xscale        - Select the xscale processor.

Available features for this target:

  32bit                    - Prefer 32-bit Thumb instrs.
  8msecext                 - Enable support for ARMv8-M Security Extensions.
  a12                      - Cortex-A12 ARM processors.
  a15                      - Cortex-A15 ARM processors.
  a17                      - Cortex-A17 ARM processors.
  a32                      - Cortex-A32 ARM processors.
  a35                      - Cortex-A35 ARM processors.
  a5                       - Cortex-A5 ARM processors.
  a53                      - Cortex-A53 ARM processors.
  a55                      - Cortex-A55 ARM processors.
  a57                      - Cortex-A57 ARM processors.
  a7                       - Cortex-A7 ARM processors.
  a72                      - Cortex-A72 ARM processors.
  a73                      - Cortex-A73 ARM processors.
  a75                      - Cortex-A75 ARM processors.
  a76                      - Cortex-A76 ARM processors.
  a77                      - Cortex-A77 ARM processors.
  a8                       - Cortex-A8 ARM processors.
  a9                       - Cortex-A9 ARM processors.
  aclass                   - Is application profile ('A' series).
  acquire-release          - Has v8 acquire/release (lda/ldaex  etc) instructions.
  aes                      - Enable AES support.
  armv2                    - ARMv2 architecture.
  armv2a                   - ARMv2a architecture.
  armv3                    - ARMv3 architecture.
  armv3m                   - ARMv3m architecture.
  armv4                    - ARMv4 architecture.
  armv4t                   - ARMv4t architecture.
  armv5t                   - ARMv5t architecture.
  armv5te                  - ARMv5te architecture.
  armv5tej                 - ARMv5tej architecture.
  armv6                    - ARMv6 architecture.
  armv6-m                  - ARMv6m architecture.
  armv6j                   - ARMv7a architecture.
  armv6k                   - ARMv6k architecture.
  armv6kz                  - ARMv6kz architecture.
  armv6s-m                 - ARMv6sm architecture.
  armv6t2                  - ARMv6t2 architecture.
  armv7-a                  - ARMv7a architecture.
  armv7-m                  - ARMv7m architecture.
  armv7-r                  - ARMv7r architecture.
  armv7e-m                 - ARMv7em architecture.
  armv7k                   - ARMv7a architecture.
  armv7s                   - ARMv7a architecture.
  armv7ve                  - ARMv7ve architecture.
  armv8-a                  - ARMv8a architecture.
  armv8-m.base             - ARMv8mBaseline architecture.
  armv8-m.main             - ARMv8mMainline architecture.
  armv8-r                  - ARMv8r architecture.
  armv8.1-a                - ARMv81a architecture.
  armv8.1-m.main           - ARMv81mMainline architecture.
  armv8.2-a                - ARMv82a architecture.
  armv8.3-a                - ARMv83a architecture.
  armv8.4-a                - ARMv84a architecture.
  armv8.5-a                - ARMv85a architecture.
  armv8.6-a                - ARMv86a architecture.
  avoid-movs-shop          - Avoid movs instructions with shifter operand.
  avoid-partial-cpsr       - Avoid CPSR partial update for OOO execution.
  bf16                     - Enable support for BFloat16 instructions.
  cde                      - Support CDE instructions.
  cdecp0                   - Coprocessor 0 ISA is CDEv1.
  cdecp1                   - Coprocessor 1 ISA is CDEv1.
  cdecp2                   - Coprocessor 2 ISA is CDEv1.
  cdecp3                   - Coprocessor 3 ISA is CDEv1.
  cdecp4                   - Coprocessor 4 ISA is CDEv1.
  cdecp5                   - Coprocessor 5 ISA is CDEv1.
  cdecp6                   - Coprocessor 6 ISA is CDEv1.
  cdecp7                   - Coprocessor 7 ISA is CDEv1.
  cheap-predicable-cpsr    - Disable +1 predication cost for instructions updating CPSR.
  cortex-a78               - Cortex-A78 ARM processors.
  cortex-x1                - Cortex-X1 ARM processors.
  crc                      - Enable support for CRC instructions.
  crypto                   - Enable support for Cryptography extensions.
  d32                      - Extend FP to 32 double registers.
  db                       - Has data barrier (dmb/dsb) instructions.
  dfb                      - Has full data barrier (dfb) instruction.
  disable-postra-scheduler - Don't schedule again after register allocation.
  dont-widen-vmovs         - Don't widen VMOVS to VMOVD.
  dotprod                  - Enable support for dot product instructions.
  dsp                      - Supports DSP instructions in ARM and/or Thumb2.
  execute-only             - Enable the generation of execute only code..
  expand-fp-mlx            - Expand VFP/NEON MLA/MLS instructions.
  exynos                   - Samsung Exynos processors.
  fp-armv8                 - Enable ARMv8 FP.
  fp-armv8d16              - Enable ARMv8 FP with only 16 d-registers.
  fp-armv8d16sp            - Enable ARMv8 FP with only 16 d-registers and no double precision.
  fp-armv8sp               - Enable ARMv8 FP with no double precision.
  fp16                     - Enable half-precision floating point.
  fp16fml                  - Enable full half-precision floating point fml instructions.
  fp64                     - Floating point unit supports double precision.
  fpao                     - Enable fast computation of positive address offsets.
  fpregs                   - Enable FP registers.
  fpregs16                 - Enable 16-bit FP registers.
  fpregs64                 - Enable 64-bit FP registers.
  fullfp16                 - Enable full half-precision floating point.
  fuse-aes                 - CPU fuses AES crypto operations.
  fuse-literals            - CPU fuses literal generation operations.
  hwdiv                    - Enable divide instructions in Thumb.
  hwdiv-arm                - Enable divide instructions in ARM mode.
  i8mm                     - Enable Matrix Multiply Int8 Extension.
  iwmmxt                   - ARMv5te architecture.
  iwmmxt2                  - ARMv5te architecture.
  krait                    - Qualcomm Krait processors.
  kryo                     - Qualcomm Kryo processors.
  lob                      - Enable Low Overhead Branch extensions.
  long-calls               - Generate calls via indirect call instructions.
  loop-align               - Prefer 32-bit alignment for loops.
  m3                       - Cortex-M3 ARM processors.
  mclass                   - Is microcontroller profile ('M' series).
  mp                       - Supports Multiprocessing extension.
  muxed-units              - Has muxed AGU and NEON/FPU.
  mve                      - Support M-Class Vector Extension with integer ops.
  mve.fp                   - Support M-Class Vector Extension with integer and floating ops.
  mve1beat                 - Model MVE instructions as a 1 beat per tick architecture.
  mve2beat                 - Model MVE instructions as a 2 beats per tick architecture.
  mve4beat                 - Model MVE instructions as a 4 beats per tick architecture.
  nacl-trap                - NaCl trap.
  neon                     - Enable NEON instructions.
  neon-fpmovs              - Convert VMOVSR, VMOVRS, VMOVS to NEON.
  neonfp                   - Use NEON for single precision FP.
  no-branch-predictor      - Has no branch predictor.
  no-movt                  - Don't use movt/movw pairs for 32-bit imms.
  no-neg-immediates        - Convert immediates and instructions to their negated or complemented equivalent when the immediate does not fit in the encoding..
  noarm                    - Does not support ARM mode execution.
  nonpipelined-vfp         - VFP instructions are not pipelined.
  perfmon                  - Enable support for Performance Monitor extensions.
  prefer-ishst             - Prefer ISHST barriers.
  prefer-vmovsr            - Prefer VMOVSR.
  prof-unpr                - Is profitable to unpredicate.
  r4                       - Cortex-R4 ARM processors.
  r5                       - Cortex-R5 ARM processors.
  r52                      - Cortex-R52 ARM processors.
  r7                       - Cortex-R7 ARM processors.
  ras                      - Enable Reliability, Availability and Serviceability extensions.
  rclass                   - Is realtime profile ('R' series).
  read-tp-hard             - Reading thread pointer from register.
  reserve-r9               - Reserve R9, making it unavailable as GPR.
  ret-addr-stack           - Has return address stack.
  sb                       - Enable v8.5a Speculation Barrier.
  sha2                     - Enable SHA1 and SHA256 support.
  slow-fp-brcc             - FP compare + branch is slow.
  slow-load-D-subreg       - Loading into D subregs is slow.
  slow-odd-reg             - VLDM/VSTM starting with an odd register is slow.
  slow-vdup32              - Has slow VDUP32 - prefer VMOV.
  slow-vgetlni32           - Has slow VGETLNi32 - prefer VMOV.
  slowfpvfmx               - Disable VFP / NEON FMA instructions.
  slowfpvmlx               - Disable VFP / NEON MAC instructions.
  soft-float               - Use software floating point features..
  splat-vfp-neon           - Splat register from VFP to NEON.
  strict-align             - Disallow all unaligned memory access.
  swift                    - Swift ARM processors.
  thumb-mode               - Thumb mode.
  thumb2                   - Enable Thumb2 instructions.
  trustzone                - Enable support for TrustZone security extensions.
  use-misched              - Use the MachineScheduler.
  v4t                      - Support ARM v4T instructions.
  v5t                      - Support ARM v5T instructions.
  v5te                     - Support ARM v5TE, v5TEj, and v5TExp instructions.
  v6                       - Support ARM v6 instructions.
  v6k                      - Support ARM v6k instructions.
  v6m                      - Support ARM v6M instructions.
  v6t2                     - Support ARM v6t2 instructions.
  v7                       - Support ARM v7 instructions.
  v7clrex                  - Has v7 clrex instruction.
  v8                       - Support ARM v8 instructions.
  v8.1a                    - Support ARM v8.1a instructions.
  v8.1m.main               - Support ARM v8-1M Mainline instructions.
  v8.2a                    - Support ARM v8.2a instructions.
  v8.3a                    - Support ARM v8.3a instructions.
  v8.4a                    - Support ARM v8.4a instructions.
  v8.5a                    - Support ARM v8.5a instructions.
  v8.6a                    - Support ARM v8.6a instructions.
  v8m                      - Support ARM v8M Baseline instructions.
  v8m.main                 - Support ARM v8M Mainline instructions.
  vfp2                     - Enable VFP2 instructions.
  vfp2sp                   - Enable VFP2 instructions with no double precision.
  vfp3                     - Enable VFP3 instructions.
  vfp3d16                  - Enable VFP3 instructions with only 16 d-registers.
  vfp3d16sp                - Enable VFP3 instructions with only 16 d-registers and no double precision.
  vfp3sp                   - Enable VFP3 instructions with no double precision.
  vfp4                     - Enable VFP4 instructions.
  vfp4d16                  - Enable VFP4 instructions with only 16 d-registers.
  vfp4d16sp                - Enable VFP4 instructions with only 16 d-registers and no double precision.
  vfp4sp                   - Enable VFP4 instructions with no double precision.
  virtualization           - Supports Virtualization extension.
  vldn-align               - Check for VLDn unaligned access.
  vmlx-forwarding          - Has multiplier accumulator forwarding.
  vmlx-hazards             - Has VMLx hazards.
  wide-stride-vfp          - Use a wide stride when allocating VFP registers.
  xscale                   - ARMv5te architecture.
  zcz                      - Has zero-cycle zeroing instructions.

Use +feature to enable a feature, or -feature to disable it.
For example, llc -mcpu=mycpu -mattr=+feature1,-feature2


================================================================================
llc --version | grep Default
Default target: x86_64-pc-msys

================================================================================
llc --version | grep armeb
armeb      - ARM (big endian)

================================================================================
llc --version | grep Default
Default target: x86_64-pc-msys

================================================================================
llvm-config --host-target
x86_64-pc-windows-msys

================================================================================
clang -v 2>&1 | grep Target
Target: x86_64-pc-windows-msys

================================================================================
clang-11 -print-targets
  Registered Targets:
    aarch64    - AArch64 (little endian)
    aarch64_32 - AArch64 (little endian ILP32)
    aarch64_be - AArch64 (big endian)
    amdgcn     - AMD GCN GPUs
    arm        - ARM
    arm64      - ARM64 (little endian)
    arm64_32   - ARM64 (little endian ILP32)
    armeb      - ARM (big endian)
    avr        - Atmel AVR Microcontroller
    bpf        - BPF (host endian)
    bpfeb      - BPF (big endian)
    bpfel      - BPF (little endian)
    hexagon    - Hexagon
    lanai      - Lanai
    mips       - MIPS (32-bit big endian)
    mips64     - MIPS (64-bit big endian)
    mips64el   - MIPS (64-bit little endian)
    mipsel     - MIPS (32-bit little endian)
    msp430     - MSP430 [experimental]
    nvptx      - NVIDIA PTX 32-bit
    nvptx64    - NVIDIA PTX 64-bit
    ppc32      - PowerPC 32
    ppc64      - PowerPC 64
    ppc64le    - PowerPC 64 LE
    r600       - AMD GPUs HD2XXX-HD6XXX
    riscv32    - 32-bit RISC-V
    riscv64    - 64-bit RISC-V
    sparc      - Sparc
    sparcel    - Sparc LE
    sparcv9    - Sparc V9
    systemz    - SystemZ
    thumb      - Thumb
    thumbeb    - Thumb (big endian)
    wasm32     - WebAssembly 32-bit
    wasm64     - WebAssembly 64-bit
    x86        - 32-bit X86: Pentium-Pro and above
    x86-64     - 64-bit X86: EM64T and AMD64
    xcore      - XCore


================================================================================
clang -print-targets
  Registered Targets:
    aarch64    - AArch64 (little endian)
    aarch64_32 - AArch64 (little endian ILP32)
    aarch64_be - AArch64 (big endian)
    amdgcn     - AMD GCN GPUs
    arm        - ARM
    arm64      - ARM64 (little endian)
    arm64_32   - ARM64 (little endian ILP32)
    armeb      - ARM (big endian)
    avr        - Atmel AVR Microcontroller
    bpf        - BPF (host endian)
    bpfeb      - BPF (big endian)
    bpfel      - BPF (little endian)
    hexagon    - Hexagon
    lanai      - Lanai
    mips       - MIPS (32-bit big endian)
    mips64     - MIPS (64-bit big endian)
    mips64el   - MIPS (64-bit little endian)
    mipsel     - MIPS (32-bit little endian)
    msp430     - MSP430 [experimental]
    nvptx      - NVIDIA PTX 32-bit
    nvptx64    - NVIDIA PTX 64-bit
    ppc32      - PowerPC 32
    ppc64      - PowerPC 64
    ppc64le    - PowerPC 64 LE
    r600       - AMD GPUs HD2XXX-HD6XXX
    riscv32    - 32-bit RISC-V
    riscv64    - 64-bit RISC-V
    sparc      - Sparc
    sparcel    - Sparc LE
    sparcv9    - Sparc V9
    systemz    - SystemZ
    thumb      - Thumb
    thumbeb    - Thumb (big endian)
    wasm32     - WebAssembly 32-bit
    wasm64     - WebAssembly 64-bit
    x86        - 32-bit X86: Pentium-Pro and above
    x86-64     - 64-bit X86: EM64T and AMD64
    xcore      - XCore
================================================================================


clang --target=avr -mmcu=atmega328p
https://lists.llvm.org/pipermail/llvm-dev/2020-March/140262.html
https://lists.llvm.org/pipermail/llvm-dev/2020-March/140320.html
================================================================================


llc -march=avr -mattr=help

Available CPUs for this target:

  at43usb320      - Select the at43usb320 processor.
  at43usb355      - Select the at43usb355 processor.
  at76c711        - Select the at76c711 processor.
  at86rf401       - Select the at86rf401 processor.
  at90c8534       - Select the at90c8534 processor.
  at90can128      - Select the at90can128 processor.
  at90can32       - Select the at90can32 processor.
  at90can64       - Select the at90can64 processor.
  at90pwm1        - Select the at90pwm1 processor.
  at90pwm161      - Select the at90pwm161 processor.
  at90pwm2        - Select the at90pwm2 processor.
  at90pwm216      - Select the at90pwm216 processor.
  at90pwm2b       - Select the at90pwm2b processor.
  at90pwm3        - Select the at90pwm3 processor.
  at90pwm316      - Select the at90pwm316 processor.
  at90pwm3b       - Select the at90pwm3b processor.
  at90pwm81       - Select the at90pwm81 processor.
  at90s1200       - Select the at90s1200 processor.
  at90s2313       - Select the at90s2313 processor.
  at90s2323       - Select the at90s2323 processor.
  at90s2333       - Select the at90s2333 processor.
  at90s2343       - Select the at90s2343 processor.
  at90s4414       - Select the at90s4414 processor.
  at90s4433       - Select the at90s4433 processor.
  at90s4434       - Select the at90s4434 processor.
  at90s8515       - Select the at90s8515 processor.
  at90s8535       - Select the at90s8535 processor.
  at90scr100      - Select the at90scr100 processor.
  at90usb1286     - Select the at90usb1286 processor.
  at90usb1287     - Select the at90usb1287 processor.
  at90usb162      - Select the at90usb162 processor.
  at90usb646      - Select the at90usb646 processor.
  at90usb647      - Select the at90usb647 processor.
  at90usb82       - Select the at90usb82 processor.
  at94k           - Select the at94k processor.
  ata5272         - Select the ata5272 processor.
  ata5505         - Select the ata5505 processor.
  ata5790         - Select the ata5790 processor.
  ata5795         - Select the ata5795 processor.
  ata6285         - Select the ata6285 processor.
  ata6286         - Select the ata6286 processor.
  ata6289         - Select the ata6289 processor.
  atmega103       - Select the atmega103 processor.
  atmega128       - Select the atmega128 processor.
  atmega1280      - Select the atmega1280 processor.
  atmega1281      - Select the atmega1281 processor.
  atmega1284      - Select the atmega1284 processor.
  atmega1284p     - Select the atmega1284p processor.
  atmega1284rfr2  - Select the atmega1284rfr2 processor.
  atmega128a      - Select the atmega128a processor.
  atmega128rfa1   - Select the atmega128rfa1 processor.
  atmega128rfr2   - Select the atmega128rfr2 processor.
  atmega16        - Select the atmega16 processor.
  atmega161       - Select the atmega161 processor.
  atmega162       - Select the atmega162 processor.
  atmega163       - Select the atmega163 processor.
  atmega164a      - Select the atmega164a processor.
  atmega164p      - Select the atmega164p processor.
  atmega164pa     - Select the atmega164pa processor.
  atmega165       - Select the atmega165 processor.
  atmega165a      - Select the atmega165a processor.
  atmega165p      - Select the atmega165p processor.
  atmega165pa     - Select the atmega165pa processor.
  atmega168       - Select the atmega168 processor.
  atmega168a      - Select the atmega168a processor.
  atmega168p      - Select the atmega168p processor.
  atmega168pa     - Select the atmega168pa processor.
  atmega169       - Select the atmega169 processor.
  atmega169a      - Select the atmega169a processor.
  atmega169p      - Select the atmega169p processor.
  atmega169pa     - Select the atmega169pa processor.
  atmega16a       - Select the atmega16a processor.
  atmega16hva     - Select the atmega16hva processor.
  atmega16hva2    - Select the atmega16hva2 processor.
  atmega16hvb     - Select the atmega16hvb processor.
  atmega16hvbrevb - Select the atmega16hvbrevb processor.
  atmega16m1      - Select the atmega16m1 processor.
  atmega16u2      - Select the atmega16u2 processor.
  atmega16u4      - Select the atmega16u4 processor.
  atmega2560      - Select the atmega2560 processor.
  atmega2561      - Select the atmega2561 processor.
  atmega2564rfr2  - Select the atmega2564rfr2 processor.
  atmega256rfr2   - Select the atmega256rfr2 processor.
  atmega32        - Select the atmega32 processor.
  atmega323       - Select the atmega323 processor.
  atmega324a      - Select the atmega324a processor.
  atmega324p      - Select the atmega324p processor.
  atmega324pa     - Select the atmega324pa processor.
  atmega325       - Select the atmega325 processor.
  atmega3250      - Select the atmega3250 processor.
  atmega3250a     - Select the atmega3250a processor.
  atmega3250p     - Select the atmega3250p processor.
  atmega3250pa    - Select the atmega3250pa processor.
  atmega325a      - Select the atmega325a processor.
  atmega325p      - Select the atmega325p processor.
  atmega325pa     - Select the atmega325pa processor.
  atmega328       - Select the atmega328 processor.
  atmega328p      - Select the atmega328p processor.
  atmega329       - Select the atmega329 processor.
  atmega3290      - Select the atmega3290 processor.
  atmega3290a     - Select the atmega3290a processor.
  atmega3290p     - Select the atmega3290p processor.
  atmega3290pa    - Select the atmega3290pa processor.
  atmega329a      - Select the atmega329a processor.
  atmega329p      - Select the atmega329p processor.
  atmega329pa     - Select the atmega329pa processor.
  atmega32a       - Select the atmega32a processor.
  atmega32c1      - Select the atmega32c1 processor.
  atmega32hvb     - Select the atmega32hvb processor.
  atmega32hvbrevb - Select the atmega32hvbrevb processor.
  atmega32m1      - Select the atmega32m1 processor.
  atmega32u2      - Select the atmega32u2 processor.
  atmega32u4      - Select the atmega32u4 processor.
  atmega32u6      - Select the atmega32u6 processor.
  atmega406       - Select the atmega406 processor.
  atmega48        - Select the atmega48 processor.
  atmega48a       - Select the atmega48a processor.
  atmega48p       - Select the atmega48p processor.
  atmega48pa      - Select the atmega48pa processor.
  atmega64        - Select the atmega64 processor.
  atmega640       - Select the atmega640 processor.
  atmega644       - Select the atmega644 processor.
  atmega644a      - Select the atmega644a processor.
  atmega644p      - Select the atmega644p processor.
  atmega644pa     - Select the atmega644pa processor.
  atmega644rfr2   - Select the atmega644rfr2 processor.
  atmega645       - Select the atmega645 processor.
  atmega6450      - Select the atmega6450 processor.
  atmega6450a     - Select the atmega6450a processor.
  atmega6450p     - Select the atmega6450p processor.
  atmega645a      - Select the atmega645a processor.
  atmega645p      - Select the atmega645p processor.
  atmega649       - Select the atmega649 processor.
  atmega6490      - Select the atmega6490 processor.
  atmega6490a     - Select the atmega6490a processor.
  atmega6490p     - Select the atmega6490p processor.
  atmega649a      - Select the atmega649a processor.
  atmega649p      - Select the atmega649p processor.
  atmega64a       - Select the atmega64a processor.
  atmega64c1      - Select the atmega64c1 processor.
  atmega64hve     - Select the atmega64hve processor.
  atmega64m1      - Select the atmega64m1 processor.
  atmega64rfr2    - Select the atmega64rfr2 processor.
  atmega8         - Select the atmega8 processor.
  atmega8515      - Select the atmega8515 processor.
  atmega8535      - Select the atmega8535 processor.
  atmega88        - Select the atmega88 processor.
  atmega88a       - Select the atmega88a processor.
  atmega88p       - Select the atmega88p processor.
  atmega88pa      - Select the atmega88pa processor.
  atmega8a        - Select the atmega8a processor.
  atmega8hva      - Select the atmega8hva processor.
  atmega8u2       - Select the atmega8u2 processor.
  attiny10        - Select the attiny10 processor.
  attiny102       - Select the attiny102 processor.
  attiny104       - Select the attiny104 processor.
  attiny11        - Select the attiny11 processor.
  attiny12        - Select the attiny12 processor.
  attiny13        - Select the attiny13 processor.
  attiny13a       - Select the attiny13a processor.
  attiny15        - Select the attiny15 processor.
  attiny1634      - Select the attiny1634 processor.
  attiny167       - Select the attiny167 processor.
  attiny20        - Select the attiny20 processor.
  attiny22        - Select the attiny22 processor.
  attiny2313      - Select the attiny2313 processor.
  attiny2313a     - Select the attiny2313a processor.
  attiny24        - Select the attiny24 processor.
  attiny24a       - Select the attiny24a processor.
  attiny25        - Select the attiny25 processor.
  attiny26        - Select the attiny26 processor.
  attiny261       - Select the attiny261 processor.
  attiny261a      - Select the attiny261a processor.
  attiny28        - Select the attiny28 processor.
  attiny4         - Select the attiny4 processor.
  attiny40        - Select the attiny40 processor.
  attiny4313      - Select the attiny4313 processor.
  attiny43u       - Select the attiny43u processor.
  attiny44        - Select the attiny44 processor.
  attiny44a       - Select the attiny44a processor.
  attiny45        - Select the attiny45 processor.
  attiny461       - Select the attiny461 processor.
  attiny461a      - Select the attiny461a processor.
  attiny48        - Select the attiny48 processor.
  attiny5         - Select the attiny5 processor.
  attiny828       - Select the attiny828 processor.
  attiny84        - Select the attiny84 processor.
  attiny84a       - Select the attiny84a processor.
  attiny85        - Select the attiny85 processor.
  attiny861       - Select the attiny861 processor.
  attiny861a      - Select the attiny861a processor.
  attiny87        - Select the attiny87 processor.
  attiny88        - Select the attiny88 processor.
  attiny9         - Select the attiny9 processor.
  atxmega128a1    - Select the atxmega128a1 processor.
  atxmega128a1u   - Select the atxmega128a1u processor.
  atxmega128a3    - Select the atxmega128a3 processor.
  atxmega128a3u   - Select the atxmega128a3u processor.
  atxmega128a4u   - Select the atxmega128a4u processor.
  atxmega128b1    - Select the atxmega128b1 processor.
  atxmega128b3    - Select the atxmega128b3 processor.
  atxmega128c3    - Select the atxmega128c3 processor.
  atxmega128d3    - Select the atxmega128d3 processor.
  atxmega128d4    - Select the atxmega128d4 processor.
  atxmega16a4     - Select the atxmega16a4 processor.
  atxmega16a4u    - Select the atxmega16a4u processor.
  atxmega16c4     - Select the atxmega16c4 processor.
  atxmega16d4     - Select the atxmega16d4 processor.
  atxmega16e5     - Select the atxmega16e5 processor.
  atxmega192a3    - Select the atxmega192a3 processor.
  atxmega192a3u   - Select the atxmega192a3u processor.
  atxmega192c3    - Select the atxmega192c3 processor.
  atxmega192d3    - Select the atxmega192d3 processor.
  atxmega256a3    - Select the atxmega256a3 processor.
  atxmega256a3b   - Select the atxmega256a3b processor.
  atxmega256a3bu  - Select the atxmega256a3bu processor.
  atxmega256a3u   - Select the atxmega256a3u processor.
  atxmega256c3    - Select the atxmega256c3 processor.
  atxmega256d3    - Select the atxmega256d3 processor.
  atxmega32a4     - Select the atxmega32a4 processor.
  atxmega32a4u    - Select the atxmega32a4u processor.
  atxmega32c4     - Select the atxmega32c4 processor.
  atxmega32d4     - Select the atxmega32d4 processor.
  atxmega32e5     - Select the atxmega32e5 processor.
  atxmega32x1     - Select the atxmega32x1 processor.
  atxmega384c3    - Select the atxmega384c3 processor.
  atxmega384d3    - Select the atxmega384d3 processor.
  atxmega64a1     - Select the atxmega64a1 processor.
  atxmega64a1u    - Select the atxmega64a1u processor.
  atxmega64a3     - Select the atxmega64a3 processor.
  atxmega64a3u    - Select the atxmega64a3u processor.
  atxmega64a4u    - Select the atxmega64a4u processor.
  atxmega64b1     - Select the atxmega64b1 processor.
  atxmega64b3     - Select the atxmega64b3 processor.
  atxmega64c3     - Select the atxmega64c3 processor.
  atxmega64d3     - Select the atxmega64d3 processor.
  atxmega64d4     - Select the atxmega64d4 processor.
  atxmega8e5      - Select the atxmega8e5 processor.
  avr1            - Select the avr1 processor.
  avr2            - Select the avr2 processor.
  avr25           - Select the avr25 processor.
  avr3            - Select the avr3 processor.
  avr31           - Select the avr31 processor.
  avr35           - Select the avr35 processor.
  avr4            - Select the avr4 processor.
  avr5            - Select the avr5 processor.
  avr51           - Select the avr51 processor.
  avr6            - Select the avr6 processor.
  avrtiny         - Select the avrtiny processor.
  avrxmega1       - Select the avrxmega1 processor.
  avrxmega2       - Select the avrxmega2 processor.
  avrxmega3       - Select the avrxmega3 processor.
  avrxmega4       - Select the avrxmega4 processor.
  avrxmega5       - Select the avrxmega5 processor.
  avrxmega6       - Select the avrxmega6 processor.
  avrxmega7       - Select the avrxmega7 processor.
  m3000           - Select the m3000 processor.

Available features for this target:

  addsubiw      - Enable 16-bit register-immediate addition and subtraction instructions.
  avr0          - The device is a part of the avr0 family.
  avr1          - The device is a part of the avr1 family.
  avr2          - The device is a part of the avr2 family.
  avr25         - The device is a part of the avr25 family.
  avr3          - The device is a part of the avr3 family.
  avr31         - The device is a part of the avr31 family.
  avr35         - The device is a part of the avr35 family.
  avr4          - The device is a part of the avr4 family.
  avr5          - The device is a part of the avr5 family.
  avr51         - The device is a part of the avr51 family.
  avr6          - The device is a part of the avr6 family.
  avrtiny       - The device is a part of the avrtiny family.
  break         - The device supports the `BREAK` debugging instruction.
  des           - The device supports the `DES k` encryption instruction.
  eijmpcall     - The device supports the `EIJMP`/`EICALL` instructions.
  elpm          - The device supports the ELPM instruction.
  elpmx         - The device supports the `ELPM Rd, Z[+]` instructions.
  ijmpcall      - The device supports `IJMP`/`ICALL`instructions.
  jmpcall       - The device supports the `JMP` and `CALL` instructions.
  lpm           - The device supports the `LPM` instruction.
  lpmx          - The device supports the `LPM Rd, Z[+]` instruction.
  memmappedregs - The device has CPU registers mapped in data address space.
  movw          - The device supports the 16-bit MOVW instruction.
  mul           - The device supports the multiplication instructions.
  rmw           - The device supports the read-write-modify instructions: XCH, LAS, LAC, LAT.
  smallstack    - The device has an 8-bit stack pointer.
  special       - Enable use of the entire instruction set - used for debugging.
  spm           - The device supports the `SPM` instruction.
  spmx          - The device supports the `SPM Z+` instruction.
  sram          - The device has random access memory.
  tinyencoding  - The device has Tiny core specific instruction encodings.
  xmega         - The device is a part of the xmega family.
  xmegau        - The device is a part of the xmegau family.

Use +feature to enable a feature, or -feature to disable it.
For example, llc -mcpu=mycpu -mattr=+feature1,-feature2