[CIR][CIRGen] Fix static init for unions

Author: bcardosolopes

clang/lib/CIR/CodeGen/CIRGenDecl.cpp

@@ -631,6 +631,9 @@ void CIRGenFunction::buildStaticVarDecl(const VarDecl &D,
   if (D.getType()->isVariablyModifiedType())
     llvm_unreachable("VLAs are NYI");
 
+  // Save the type in case adding the initializer forces a type change.
+  auto expectedType = addr.getType();
+
   auto var = globalOp;
 
   // CUDA's local and local static __shared__ variables should not
@@ -671,12 +674,8 @@ void CIRGenFunction::buildStaticVarDecl(const VarDecl &D,
   //
   // FIXME: It is really dangerous to store this in the map; if anyone
   // RAUW's the GV uses of this constant will be invalid.
-  //
-  // Since in CIR the address materialization is done over cir.get_global
-  // and that's already updated, update the map directly instead of using
-  // casts.
-  LocalDeclMap.find(&D)->second =
-      Address(getAddrOp.getAddr(), elemTy, alignment);
+  auto castedAddr = builder.createBitcast(getAddrOp.getAddr(), expectedType);
+  LocalDeclMap.find(&D)->second = Address(castedAddr, elemTy, alignment);
   CGM.setStaticLocalDeclAddress(&D, var);
 
   assert(!MissingFeatures::reportGlobalToASan());

clang/test/CIR/CodeGen/stmtexpr-init.c

@@ -41,7 +41,8 @@ void T2(void) {
   // LLVM-DAG: internal constant { i32, [3 x i32] } { i32 3, [3 x i32] [i32 10, i32 20, i32 30] }
   struct outer X = {ARRAY_PTR(10, 20, 30)};
 
-  // CIR-DAG: cir.cast(bitcast, %1 : !cir.ptr<!cir.ptr<![[sized_array]]>>), !cir.ptr<!cir.ptr<![[annon_struct]]>>
+  // CIR-DAG: %[[T2A:.*]] = cir.get_global @T2._a : !cir.ptr<![[annon_struct]]>
+  // CIR-DAG: cir.cast(bitcast, %[[T2A]] : !cir.ptr<![[annon_struct]]>), !cir.ptr<![[sized_array]]>
   escape(A);
   escape(&X);
 }

clang/test/CIR/CodeGen/union-init.c

@@ -12,9 +12,11 @@ void foo(int x) {
   A a = {.x = x};
 }
 
-// CHECK: ![[anon:.*]] = !cir.struct<struct  {!s32i}>
-// CHECK: #[[bfi_x:.*]] = #cir.bitfield_info<name = "x", storage_type = !u32i, size = 16, offset = 0, is_signed = true>
-// CHECK: #[[bfi_y:.*]] = #cir.bitfield_info<name = "y", storage_type = !u32i, size = 16, offset = 16, is_signed = true>
+// CHECK-DAG: ![[anon0:.*]] = !cir.struct<struct  {!u32i}>
+// CHECK-DAG: ![[anon:.*]] = !cir.struct<struct  {!s32i}>
+// CHECK-DAG: #[[bfi_x:.*]] = #cir.bitfield_info<name = "x", storage_type = !u32i, size = 16, offset = 0, is_signed = true>
+// CHECK-DAG: #[[bfi_y:.*]] = #cir.bitfield_info<name = "y", storage_type = !u32i, size = 16, offset = 16, is_signed = true>
+// CHECK-DAG: ![[anon1:.*]] = !cir.struct<union "{{.*}}" {!u32i, !cir.array<!u8i x 4>}
 
 // CHECK-LABEL:   cir.func @foo(
 // CHECK:  %[[VAL_1:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["x", init] {alignment = 4 : i64}
@@ -30,4 +32,17 @@ void foo(int x) {
 // CHECK:  cir.return
 
 union { int i; float f; } u = { };
-// CHECK: cir.global external @u = #cir.zero : ![[anon]]
+// CHECK: cir.global external @u = #cir.zero : ![[anon]]
+
+unsigned is_little(void) {
+  const union {
+    unsigned int u;
+    unsigned char c[4];
+  } one = {1};
+  return one.c[0];
+}
+
+// CHECK: cir.func @is_little
+// CHECK: %[[VAL_1:.*]] = cir.get_global @is_little.one : !cir.ptr<![[anon0]]>
+// CHECK: %[[VAL_2:.*]] = cir.cast(bitcast, %[[VAL_1]] : !cir.ptr<![[anon0]]>), !cir.ptr<![[anon1]]>
+// CHECK: %[[VAL_3:.*]] = cir.get_member %[[VAL_2]][1] {name = "c"} : !cir.ptr<![[anon1]]> -> !cir.ptr<!cir.array<!u8i x 4>>