[clang] [clang][PowerPC] Add flag to enable compatibility with GNU for complex arguments (PR #77732)

[zhijian lin via cfe-commits]

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@@ -78,6 +78,13 @@ class CodeGenOptions : public CodeGenOptionsBase {
     SRCK_InRegs    // Small structs in registers (-freg-struct-return).
   };
 
+  enum ComplexArgumentConventionKind {
+    CMPLX_Default,
+    CMPLX_OnStack,
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diggerlin wrote:

it looks you define the `CMPLX_Default` and   ` CMPLX_OnStack` , but never use them.

https://github.com/llvm/llvm-project/pull/77732