[clang] [CIR] Upstream Cast kinds for ComplexType (PR #149717)

[Amr Hesham via cfe-commits]

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@@ -207,6 +300,49 @@ void ComplexExprEmitter::emitStoreOfComplex(mlir::Location loc, mlir::Value val,
   builder.createStore(loc, val, destAddr);
 }
 
+mlir::Value ComplexExprEmitter::emitComplexToComplexCast(mlir::Value val,
+                                                         QualType srcType,
+                                                         QualType destType,
+                                                         SourceLocation loc) {
+  if (srcType == destType)
+    return val;
+
+  // Get the src/dest element type.
+  QualType srcElemTy = srcType->castAs<ComplexType>()->getElementType();
+  QualType destElemTy = destType->castAs<ComplexType>()->getElementType();
+
+  cir::CastKind castOpKind;
+  if (srcElemTy->isFloatingType() && destElemTy->isFloatingType())
+    castOpKind = cir::CastKind::float_complex;
+  else if (srcElemTy->isFloatingType() && destElemTy->isIntegerType())
+    castOpKind = cir::CastKind::float_complex_to_int_complex;
+  else if (srcElemTy->isIntegerType() && destElemTy->isFloatingType())
+    castOpKind = cir::CastKind::int_complex_to_float_complex;
+  else if (srcElemTy->isIntegerType() && destElemTy->isIntegerType())
+    castOpKind = cir::CastKind::int_complex;
+  else
+    llvm_unreachable("unexpected src type or dest type");
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AmrDeveloper wrote:

Yes, but this implementation was because this helper will used later in other places for example `ComplexExprEmitter::emitCompoundAssignLValue`, i will check the other cases if we can pass the kind directly

https://github.com/llvm/llvm-project/pull/149717