[llvm] [RISCV] Remove the mucounteren alternate name for CSR 0x320. (PR #132498)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mc

Author: Craig Topper (topperc)

<details>
<summary>Changes</summary>

This is the old name for 0x320 from privilege spec 1.9. It has different semantics than mcountinhibit that is at that address now.

It doesn't look like binutils supports this name anymore so I don't think llvm should.

---
Full diff: https://github.com/llvm/llvm-project/pull/132498.diff


2 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVSystemOperands.td (-2) 
- (modified) llvm/test/MC/RISCV/machine-csr-names.s (-14) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVSystemOperands.td b/llvm/lib/Target/RISCV/RISCVSystemOperands.td
index 5b46e7df25fc8..c03ebe585079a 100644
--- a/llvm/lib/Target/RISCV/RISCVSystemOperands.td
+++ b/llvm/lib/Target/RISCV/RISCVSystemOperands.td
@@ -301,8 +301,6 @@ foreach i = 3...31 in
 // Machine Counter Setup
 //===----------------------------------------------------------------------===//
 def : SysReg<"mcountinhibit", 0x320>;
-let isAltName = 1 in
-def : SysReg<"mucounteren", 0x320>;
 
 // mhpmevent3-mhpmevent31 at 0x323-0x33F.
 foreach i = 3...31 in
diff --git a/llvm/test/MC/RISCV/machine-csr-names.s b/llvm/test/MC/RISCV/machine-csr-names.s
index ba2a79f1f6aa1..356a28b347b45 100644
--- a/llvm/test/MC/RISCV/machine-csr-names.s
+++ b/llvm/test/MC/RISCV/machine-csr-names.s
@@ -1972,20 +1972,6 @@ csrrs t1, mcountinhibit, zero
 # uimm12
 csrrs t2, 0x320, zero
 
-# mucounteren
-# name
-# CHECK-INST: csrrs t1, mcountinhibit, zero
-# CHECK-ENC:  encoding: [0x73,0x23,0x00,0x32]
-# CHECK-INST-ALIAS: csrr t1, mcountinhibit
-# uimm12
-# CHECK-INST: csrrs t2, mcountinhibit, zero
-# CHECK-ENC:  encoding: [0xf3,0x23,0x00,0x32]
-# CHECK-INST-ALIAS: csrr t2, mcountinhibit
-# name
-csrrs t1, mucounteren, zero
-# uimm12
-csrrs t2, 0x320, zero
-
 # mhpmevent3
 # name
 # CHECK-INST: csrrs t1, mhpmevent3, zero

``````````

</details>


https://github.com/llvm/llvm-project/pull/132498