[llvm] [RISCV] Add hasSideEffects = true to ReadFRM (PR #139864)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Gergely Futo (futog)

<details>
<summary>Changes</summary>

ReadFRM should not be optimized out.

---
Full diff: https://github.com/llvm/llvm-project/pull/139864.diff


1 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVInstrInfo.td (+2) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
index e9bdeb88e4ca8..88ee311b51543 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -2006,7 +2006,9 @@ class SwapSysRegImm<SysReg SR, list<Register> Regs>
   let Defs = Regs;
 }
 
+let hasSideEffects = true in
 def ReadFRM : ReadSysReg<SysRegFRM, [FRM]>;
+
 let hasPostISelHook = 1 in {
 def WriteFRM : WriteSysReg<SysRegFRM, [FRM]>;
 def WriteFRMImm : WriteSysRegImm<SysRegFRM, [FRM]>;

``````````

</details>


https://github.com/llvm/llvm-project/pull/139864