[CIR] Backport global initializer for ComplexType (#1956)

Backport global initializer for ComplexType from the upstream

Author: AmrDeveloper

clang/lib/CIR/CodeGen/CIRGenCXX.cpp

@@ -204,7 +204,8 @@ static void emitDeclInit(CIRGenFunction &cgf, const VarDecl *varDecl,
       cgf.emitScalarInit(init, cgf.getLoc(varDecl->getLocation()), lv, false);
     return;
   case cir::TEK_Complex:
-    llvm_unreachable("complext evaluation NYI");
+    cgf.emitComplexExprIntoLValue(init, lv, /*isInit=*/true);
+    return;
   case cir::TEK_Aggregate:
     cgf.emitAggExpr(init,
                     AggValueSlot::forLValue(lv, AggValueSlot::IsDestructed,

clang/test/CIR/CodeGen/global-init.cpp

@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir -mmlir --mlir-print-ir-before=cir-lowering-prepare %s -o %t.cir 2> %t-before.cir
+// RUN: FileCheck --input-file=%t-before.cir %s --check-prefix=CIR-BEFORE-LPP
+// RUN: FileCheck --input-file=%t.cir %s --check-prefix=CIR
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s --check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s --check-prefix=OGCG
+
+float num;
+float _Complex a = {num, num};
+
+// CIR-BEFORE-LPP: cir.global external @num = #cir.fp<0.000000e+00> : !cir.float
+// CIR-BEFORE-LPP: cir.global external @a = ctor : !cir.complex<!cir.float> {
+// CIR-BEFORE-LPP:  %[[THIS:.*]] = cir.get_global @a : !cir.ptr<!cir.complex<!cir.float>>
+// CIR-BEFORE-LPP:  %[[NUM:.*]] = cir.get_global @num : !cir.ptr<!cir.float>
+// CIR-BEFORE-LPP:  %[[REAL:.*]] = cir.load{{.*}} %[[NUM]] : !cir.ptr<!cir.float>, !cir.float
+// CIR-BEFORE-LPP:  %[[NUM:.*]] = cir.get_global @num : !cir.ptr<!cir.float>
+// CIR-BEFORE-LPP:  %[[IMAG:.*]] = cir.load{{.*}} %[[NUM]] : !cir.ptr<!cir.float>, !cir.float
+// CIR-BEFORE-LPP:  %[[COMPLEX_VAL:.*]] = cir.complex.create %[[REAL]], %[[IMAG]] : !cir.float -> !cir.complex<!cir.float>
+// CIR-BEFORE-LPP:  cir.store{{.*}} %[[COMPLEX_VAL:.*]], %[[THIS]] : !cir.complex<!cir.float>, !cir.ptr<!cir.complex<!cir.float>>
+// CIR-BEFORE-LPP: }
+
+// CIR:  cir.global external @num = #cir.fp<0.000000e+00> : !cir.float
+// CIR:  cir.global external @a = #cir.zero : !cir.complex<!cir.float>
+// CIR:  cir.func internal private @__cxx_global_var_init()
+// CIR:   %[[A_ADDR:.*]] = cir.get_global @a : !cir.ptr<!cir.complex<!cir.float>>
+// CIR:   %[[NUM:.*]] = cir.get_global @num : !cir.ptr<!cir.float>
+// CIR:   %[[REAL:.*]] = cir.load{{.*}} %[[NUM]] : !cir.ptr<!cir.float>, !cir.float
+// CIR:   %[[NUM:.*]] = cir.get_global @num : !cir.ptr<!cir.float>
+// CIR:   %[[IMAG:.*]] = cir.load{{.*}} %[[NUM]] : !cir.ptr<!cir.float>, !cir.float
+// CIR:   %[[COMPLEX_VAL:.*]] = cir.complex.create %[[REAL]], %[[IMAG]] : !cir.float -> !cir.complex<!cir.float>
+// CIR:   cir.store{{.*}} %[[COMPLEX_VAL]], %[[A_ADDR]] : !cir.complex<!cir.float>, !cir.ptr<!cir.complex<!cir.float>>
+
+// LLVM: define internal void @__cxx_global_var_init()
+// LLVM:   %[[REAL:.*]] = load float, ptr @num, align 4
+// LLVM:   %[[IMAG:.*]] = load float, ptr @num, align 4
+// LLVM:   %[[TMP_COMPLEX_VAL:.*]] = insertvalue { float, float } {{.*}}, float %[[REAL]], 0
+// LLVM:   %[[COMPLEX_VAL:.*]] = insertvalue { float, float } %[[TMP_COMPLEX_VAL]], float %[[IMAG]], 1
+// LLVM:   store { float, float } %[[COMPLEX_VAL]], ptr @a, align 4
+
+// OGCG: define internal void @__cxx_global_var_init() {{.*}} section ".text.startup"
+// OGCG:   %[[REAL:.*]] = load float, ptr @num, align 4
+// OGCG:   %[[IMAG:.*]] = load float, ptr @num, align 4
+// OGCG:   store float %[[REAL]], ptr @a, align 4
+// OGCG:   store float %[[IMAG]], ptr getelementptr inbounds nuw ({ float, float }, ptr @a, i32 0, i32 1), align 4