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

[Wang Pengcheng via llvm-commits]

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@@ -349,36 +359,46 @@ bool RISCVExpandPseudo::expandRV32ZdinxLoad(MachineBasicBlock &MBB,
   Register Hi =
       TRI->getSubReg(MBBI->getOperand(0).getReg(), RISCV::sub_gpr_odd);
 
+  assert(MBBI->hasOneMemOperand() && "Expected mem operand");
+  MachineMemOperand *OldMMO = MBBI->memoperands().front();
+  MachineFunction *MF = MBB.getParent();
+  MachineMemOperand *MMOLo = MF->getMachineMemOperand(OldMMO, 0, 4);
+  MachineMemOperand *MMOHi = MF->getMachineMemOperand(OldMMO, 4, 4);
+
   // If the register of operand 1 is equal to the Lo register, then swap the
   // order of loading the Lo and Hi statements.
   bool IsOp1EqualToLo = Lo == MBBI->getOperand(1).getReg();
   // Order: Lo, Hi
   if (!IsOp1EqualToLo) {
-    BuildMI(MBB, MBBI, DL, TII->get(RISCV::LW), Lo)
-        .addReg(MBBI->getOperand(1).getReg())
-        .add(MBBI->getOperand(2));
+    auto MIBLo = BuildMI(MBB, MBBI, DL, TII->get(RISCV::LW), Lo)
+                     .addReg(MBBI->getOperand(1).getReg())
+                     .add(MBBI->getOperand(2));
+    MIBLo.setMemRefs(MMOLo);
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wangpc-pp wrote:

Remove `MIBLo` and chain the call `setMemRefs` after `BuildMI`?

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