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

[Ulrich Weigand via llvm-commits]

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@@ -1211,6 +1211,15 @@ class TargetInfo : public TransferrableTargetInfo,
       TiedOperand = N;
       // Don't copy Name or constraint string.
     }
+
+    // Output operand bounds can be set by target.
+    void setOutputOperandBounds(unsigned Min, unsigned Max) {
+      setRequiresImmediate(Min, Max);
+    }
+    std::pair<unsigned, unsigned> getOutputOperandBounds() const {
+      return ImmRange.isConstrained ? std::make_pair(ImmRange.Min, ImmRange.Max)
+                                    : std::make_pair(0, 0);
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uweigand wrote:

It might be clearer to have this function return a std::optional reflecting whether or not the bound is present.

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