[llvm] [RISCV] Preserve MMO when expanding PseudoRV32ZdinxSD/PseudoRV32ZdinxLD. (PR #85877)

[Wang Pengcheng via llvm-commits]

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@@ -312,26 +312,40 @@ bool RISCVExpandPseudo::expandRV32ZdinxStore(MachineBasicBlock &MBB,
       TRI->getSubReg(MBBI->getOperand(0).getReg(), RISCV::sub_gpr_even);
   Register Hi =
       TRI->getSubReg(MBBI->getOperand(0).getReg(), RISCV::sub_gpr_odd);
-  BuildMI(MBB, MBBI, DL, TII->get(RISCV::SW))
-      .addReg(Lo, getKillRegState(MBBI->getOperand(0).isKill()))
-      .addReg(MBBI->getOperand(1).getReg())
-      .add(MBBI->getOperand(2));
+  auto MIBLo = BuildMI(MBB, MBBI, DL, TII->get(RISCV::SW))
+                   .addReg(Lo, getKillRegState(MBBI->getOperand(0).isKill()))
+                   .addReg(MBBI->getOperand(1).getReg())
+                   .add(MBBI->getOperand(2));
+
+  MachineMemOperand *MMOHi = nullptr;
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wangpc-pp wrote:

Make this a list (can be empty) so we don't need to know if `MMOHi` is nullptr and `setMemRefs` directly?

https://github.com/llvm/llvm-project/pull/85877