[clang] [llvm] Add support for flag output operand "=@cc" for SystemZ. (PR #125970)

[Ulrich Weigand via llvm-commits]

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@@ -1514,10 +1516,21 @@ SystemZTargetLowering::getConstraintType(StringRef Constraint) const {
     default:
       break;
     }
+  } else if (Constraint.size() == 5 && Constraint.starts_with("{")) {
+    if (StringRef("{@cc}").compare(Constraint) == 0)
+      return C_Other;
   }
   return TargetLowering::getConstraintType(Constraint);
 }
 
+// Convert condition code in CCReg to an i32 value.
+static SDValue getCCResult(SelectionDAG &DAG, SDValue CCReg) {
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uweigand wrote:

Just a minor nit, but this ended up in a weird place now.  Why not just move it to directly before the `LowerAsmOutputForConstraint` routine?

https://github.com/llvm/llvm-project/pull/125970