[llvm] [MachineOutliner] Preserve regmasks in calls to outlined functions (PR #120940)

[Ellis Hoag via llvm-commits]

================
@@ -1153,6 +1160,24 @@ bool MachineOutliner::outline(
             MI->getMF()->eraseCallSiteInfo(MI);
         }
 
+        if (!RegMasks.empty()) {
+          if (RegMasks.size() == 1) {
+            CallInst->addOperand(
+                MachineOperand::CreateRegMask(*RegMasks.begin()));
+          } else {
+            uint32_t *RegMask = MF->allocateRegMask();
+            unsigned NumRegs =
+                MF->getSubtarget().getRegisterInfo()->getNumRegs();
+            unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
+            memset(RegMask, UINT32_MAX, Size * sizeof(RegMask[0]));
+            for (const uint32_t *Mask : RegMasks) {
+              for (unsigned I = 0; I < Size; ++I)
+                RegMask[I] &= Mask[I];
+            }
----------------
ellishg wrote:

```suggestion
            for (const uint32_t *Mask : RegMasks)
              for (unsigned I = 0; I < Size; ++I)
                RegMask[I] &= Mask[I];
```

https://github.com/llvm/llvm-project/pull/120940