[clang] [llvm] Add AMO load with Compare and Swap Not Equal (PR #178061)

[Nikita Popov via cfe-commits]

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@@ -1729,6 +1729,27 @@ void PPCAsmPrinter::emitInstruction(const MachineInstr *MI) {
     EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::EnforceIEIO));
     return;
   }
+  case PPC::BL8:
+  case PPC::BL8_NOP: {
+    const MachineOperand &MO = MI->getOperand(0);
+    if (MO.isSymbol()) {
+      StringRef Name = MO.getSymbolName();
+      Name.consume_front(".");
+      Name.consume_back("[PR]");
+      bool IsLWAT = Name == "__lwat_csne_pseudo";
+      bool IsLDAT = Name == "__ldat_csne_pseudo";
+      if (IsLWAT || IsLDAT) {
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nikic wrote:

I'm not sure I follow. It looks like the registers are fixed here, so why does this need a new register class? Wouldn't it be sufficient to mark x4 and x5 as implicit-def for the instruction?

https://github.com/llvm/llvm-project/pull/178061