diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -1195,43 +1195,35 @@
   let Uses = Regs;
 }
 
-class WriteSysReg<SysReg SR, list<Register> Regs>
-  : Pseudo<(outs), (ins GPR:$val),
-           [(riscv_write_csr (XLenVT SR.Encoding), GPR:$val)]>,
-    PseudoInstExpansion<(CSRRW X0, SR.Encoding, GPR:$val)> {
-  let hasSideEffects = 0;
-  let Defs = Regs;
-}
-
-class WriteSysRegImm<SysReg SR, list<Register> Regs>
-  : Pseudo<(outs), (ins uimm5:$val),
-           [(riscv_write_csr (XLenVT SR.Encoding), uimm5:$val)]>,
-    PseudoInstExpansion<(CSRRWI X0, SR.Encoding, uimm5:$val)> {
-  let hasSideEffects = 0;
-  let Defs = Regs;
-}
-
-class SwapSysReg<SysReg SR, list<Register> Regs>
-  : Pseudo<(outs GPR:$rd), (ins GPR:$val),
-           [(set GPR:$rd, (riscv_swap_csr (XLenVT SR.Encoding), GPR:$val))]>,
-    PseudoInstExpansion<(CSRRW GPR:$rd, SR.Encoding, GPR:$val)> {
-  let hasSideEffects = 0;
-  let Uses = Regs;
-  let Defs = Regs;
+// Need to use GPRNoX0 for $val to prevent X0 copies coalescing into this
+// causing it to become CSRRW x0, x0 which is a NOP.
+multiclass WriteSysReg<SysReg SR, list<Register> Regs> {
+  let hasSideEffects = 0, Defs = Regs in {
+    def NAME : Pseudo<(outs), (ins GPRNoX0:$val),
+                      [(riscv_write_csr (XLenVT SR.Encoding), GPRNoX0:$val)]>,
+               PseudoInstExpansion<(CSRRW X0, SR.Encoding, GPR:$val)>;
+    def Imm : Pseudo<(outs), (ins uimm5:$val),
+                     [(riscv_write_csr (XLenVT SR.Encoding), uimm5:$val)]>,
+              PseudoInstExpansion<(CSRRWI X0, SR.Encoding, uimm5:$val)>;
+  }
 }
 
-class SwapSysRegImm<SysReg SR, list<Register> Regs>
-  : Pseudo<(outs GPR:$rd), (ins uimm5:$val),
-           [(set GPR:$rd, (riscv_swap_csr (XLenVT SR.Encoding), uimm5:$val))]>,
-    PseudoInstExpansion<(CSRRWI GPR:$rd, SR.Encoding, uimm5:$val)> {
-  let hasSideEffects = 0;
-  let Uses = Regs;
-  let Defs = Regs;
+// Need to use GPRNoX0 for $val to prevent copies from X0 coalescing into this
+// causing it to become CSRRW rd, x0 which will not write the CSR.
+multiclass SwapSysReg<SysReg SR, list<Register> Regs> {
+  let hasSideEffects = 0, Uses = Regs, Defs = Regs in {
+    def NAME : Pseudo<(outs GPR:$rd), (ins GPRNoX0:$val),
+                      [(set GPR:$rd,
+                        (riscv_swap_csr (XLenVT SR.Encoding), GPRNoX0:$val))]>,
+               PseudoInstExpansion<(CSRRW GPR:$rd, SR.Encoding, GPR:$val)>;
+    def Imm : Pseudo<(outs GPR:$rd), (ins uimm5:$val),
+                     [(set GPR:$rd,
+                       (riscv_swap_csr (XLenVT SR.Encoding), uimm5:$val))]>;
+  }
 }
 
 def ReadFRM : ReadSysReg<SysRegFRM, [FRM]>;
-def WriteFRM : WriteSysReg<SysRegFRM, [FRM]>;
-def WriteFRMImm : WriteSysRegImm<SysRegFRM, [FRM]>;
+defm WriteFRM : WriteSysReg<SysRegFRM, [FRM]>;
 
 /// Other pseudo-instructions