[clang] [llvm] [RISCV] SiFive CLIC Support (PR #132481)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-expensive-checks-debian` running on `gribozavr4` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/16/builds/17991

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/RISCV/sifive-interrupt-attr.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/llc -mtriple riscv32-unknown-elf -mattr=+experimental-xsfmclic -o - /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/RISCV/sifive-interrupt-attr.ll    | /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/RISCV/sifive-interrupt-attr.ll --check-prefix=RV32 # RUN: at line 2
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/llc -mtriple riscv32-unknown-elf -mattr=+experimental-xsfmclic -o - /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/RISCV/sifive-interrupt-attr.ll
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/RISCV/sifive-interrupt-attr.ll --check-prefix=RV32

# After Prologue/Epilogue Insertion & Frame Finalization
# Machine code for function preemptible_empty: NoPHIs, TracksLiveness, NoVRegs, TiedOpsRewritten, TracksDebugUserValues
Frame Objects:
  fi#0: size=4, align=4, at location [SP-4]
  fi#1: size=4, align=4, at location [SP-8]

bb.0 (%ir-block.0):
  $x2 = frame-setup ADDI $x2, -16
  frame-setup CFI_INSTRUCTION def_cfa_offset 16
  frame-setup SW killed $x8, $x2, 12 :: (store (s32) into %stack.0)
  frame-setup SW killed $x9, $x2, 8 :: (store (s32) into %stack.1)
  $x8 = frame-setup CSRRS 834, $x0
  $x9 = frame-setup CSRRS 833, $x0
  frame-setup CSRRSI $x0, 768, 8
  frame-setup CSRRCI $x0, 768, 8
  frame-setup CSRRW $x0, 833, killed $x9
  frame-setup CSRRW $x0, 834, killed $x8
  $x9 = frame-setup LW $x2, 8 :: (load (s32) from %stack.1)
  $x8 = frame-setup LW $x2, 12 :: (load (s32) from %stack.0)
  $x2 = frame-destroy ADDI $x2, 16
  frame-destroy CFI_INSTRUCTION def_cfa_offset 0
  MRET

# End machine code for function preemptible_empty.

*** Bad machine code: Explicit definition marked as use ***
- function:    preemptible_empty
- basic block: %bb.0  (0xa8170f0)
- instruction: frame-setup CSRRSI $x0, 768, 8
- operand 0:   $x0

*** Bad machine code: Explicit definition marked as use ***
- function:    preemptible_empty
- basic block: %bb.0  (0xa8170f0)
- instruction: frame-setup CSRRCI $x0, 768, 8
- operand 0:   $x0

*** Bad machine code: Explicit definition marked as use ***
- function:    preemptible_empty
- basic block: %bb.0  (0xa8170f0)
- instruction: frame-setup CSRRW $x0, 833, killed $x9
...

```

</details>

https://github.com/llvm/llvm-project/pull/132481