[CIR] Backport MemberExpr support for ComplexType (#1838)

Backporting MemberExpr support for ComplexType from the upstream

Author: AmrDeveloper

clang/lib/CIR/CodeGen/CIRGenExpr.cpp

@@ -3272,7 +3272,9 @@ CIRGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
 
 CIRGenFunction::ConstantEmission
 CIRGenFunction::tryEmitAsConstant(const MemberExpr *ME) {
-  llvm_unreachable("NYI");
+  if (DeclRefExpr *dre = tryToConvertMemberExprToDeclRefExpr(*this, ME))
+    return tryEmitAsConstant(dre);
+  return ConstantEmission();
 }
 
 mlir::Value CIRGenFunction::emitScalarConstant(

clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp

@@ -109,7 +109,14 @@ class ComplexExprEmitter : public StmtVisitor<ComplexExprEmitter, mlir::Value> {
     llvm_unreachable("NYI");
   }
   mlir::Value VisitArraySubscriptExpr(Expr *E) { return emitLoadOfLValue(E); }
-  mlir::Value VisitMemberExpr(MemberExpr *ME) { llvm_unreachable("NYI"); }
+
+  mlir::Value VisitMemberExpr(MemberExpr *ME) {
+    if (CIRGenFunction::ConstantEmission constant = CGF.tryEmitAsConstant(ME)) {
+      llvm_unreachable("VisitMemberExpr tryEmitAsConstant");
+    }
+    return emitLoadOfLValue(ME);
+  }
+
   mlir::Value VisitOpaqueValueExpr(OpaqueValueExpr *E) {
     llvm_unreachable("NYI");
   }

clang/test/CIR/CodeGen/complex.cpp

@@ -102,6 +102,29 @@ int _Complex complex_real_operator_on_rvalue() {
 // LLVM: %[[TMP_RET:.*]] = load { i32, i32 }, ptr %[[RET_ADDR]], align 4
 // LLVM: ret { i32, i32 } %[[TMP_RET]]
 
+void complex_member_expr() {
+  struct Wrapper {
+    int _Complex c;
+  };
+
+  Wrapper w;
+  int r = __real__ w.c;
+}
+
+// CIR: %[[W_ADDR:.*]] = cir.alloca !rec_Wrapper, !cir.ptr<!rec_Wrapper>, ["w"]
+// CIR: %[[REAL_ADDR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["r", init]
+// CIR: %[[ELEM_PTR:.*]] = cir.get_member %[[W_ADDR]][0] {name = "c"} : !cir.ptr<!rec_Wrapper> -> !cir.ptr<!cir.complex<!s32i>>
+// CIR: %[[TMP_ELEM_PTR:.*]] = cir.load{{.*}} %[[ELEM_PTR]] : !cir.ptr<!cir.complex<!s32i>>, !cir.complex<!s32i>
+// CIR: %[[REAL:.*]] = cir.complex.real %[[TMP_ELEM_PTR]] : !cir.complex<!s32i> -> !s32i
+// CIR: cir.store{{.*}} %[[REAL]], %[[REAL_ADDR]] : !s32i, !cir.ptr<!s32i>
+
+// LLVM: %[[W_ADDR:.*]] = alloca %struct.Wrapper, i64 1, align 4
+// LLVM: %[[REAL_ADDR:.*]] = alloca i32, i64 1, align 4
+// LLVM: %[[ELEM_PTR:.*]] = getelementptr %struct.Wrapper, ptr %[[W_ADDR]], i32 0, i32 0
+// LLVM: %[[TMP_ELEM_PTR:.*]] = load { i32, i32 }, ptr %[[ELEM_PTR]], align 4
+// LLVM: %[[REAL:.*]] = extractvalue { i32, i32 } %[[TMP_ELEM_PTR]], 0
+// LLVM: store i32 %[[REAL]], ptr %[[REAL_ADDR]], align 4
+
 int _Complex complex_imag_operator_on_rvalue() {
   int imag = __imag__ complex_imag_operator_on_rvalue();
   return {};