[clang] [CIR] ConstRecordBuilder check if attribute present before casting (PR #164575)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper created https://github.com/llvm/llvm-project/pull/164575

Fix the crash because in `ConstRecordBuilder::build` we cast to TypedAttr then we check if it null, but in case that the result from emitter is nullptr, that cast crash, In this PR I fixed the order to check first if it not null, then casting to the TypedAttr

>From c472394c1f49d0b218f3de8f53fcd20b89e7e117 Mon Sep 17 00:00:00 2001
From: Amr Hesham <amr96 at programmer.net>
Date: Wed, 22 Oct 2025 09:30:04 +0200
Subject: [PATCH] [CIR] ConstRecordBuilder check if attribute present before
 casting

---
 clang/lib/CIR/CodeGen/CIRGenExprConstant.cpp | 20 +++++++-------------
 clang/test/CIR/CodeGen/struct-init.cpp       | 17 +++++++++++++++++
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenExprConstant.cpp b/clang/lib/CIR/CodeGen/CIRGenExprConstant.cpp
index 800262aac8fa4..4d5d0bd78530a 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprConstant.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprConstant.cpp
@@ -612,10 +612,7 @@ bool ConstRecordBuilder::applyZeroInitPadding(const ASTRecordLayout &layout,
 }
 
 bool ConstRecordBuilder::build(InitListExpr *ile, bool allowOverwrite) {
-  RecordDecl *rd = ile->getType()
-                       ->castAs<clang::RecordType>()
-                       ->getDecl()
-                       ->getDefinitionOrSelf();
+  RecordDecl *rd = ile->getType()->castAsRecordDecl();
   const ASTRecordLayout &layout = cgm.getASTContext().getASTRecordLayout(rd);
 
   // Bail out if we have base classes. We could support these, but they only
@@ -671,17 +668,14 @@ bool ConstRecordBuilder::build(InitListExpr *ile, bool allowOverwrite) {
       return false;
     }
 
-    mlir::TypedAttr eltInit;
-    if (init)
-      eltInit = mlir::cast<mlir::TypedAttr>(
-          emitter.tryEmitPrivateForMemory(init, field->getType()));
-    else
-      eltInit = mlir::cast<mlir::TypedAttr>(emitter.emitNullForMemory(
-          cgm.getLoc(ile->getSourceRange()), field->getType()));
-
-    if (!eltInit)
+    mlir::Attribute eltInitAttr =
+        init ? emitter.tryEmitPrivateForMemory(init, field->getType())
+             : emitter.emitNullForMemory(cgm.getLoc(ile->getSourceRange()),
+                                         field->getType());
+    if (!eltInitAttr)
       return false;
 
+    mlir::TypedAttr eltInit = mlir::cast<mlir::TypedAttr>(eltInitAttr);
     if (!field->isBitField()) {
       // Handle non-bitfield members.
       if (!appendField(field, layout.getFieldOffset(index), eltInit,
diff --git a/clang/test/CIR/CodeGen/struct-init.cpp b/clang/test/CIR/CodeGen/struct-init.cpp
index cb509994d1cbf..e1e8cda6fe9fb 100644
--- a/clang/test/CIR/CodeGen/struct-init.cpp
+++ b/clang/test/CIR/CodeGen/struct-init.cpp
@@ -25,6 +25,23 @@ StructWithDefaultInit swdi = {};
 // LLVM: @swdi = global %struct.StructWithDefaultInit { i32 2 }, align 4
 // OGCG: @swdi = global %struct.StructWithDefaultInit { i32 2 }, align 4
 
+struct StructWithFieldInitFromConst {
+  int a : 10;
+  int b = a;
+};
+
+StructWithFieldInitFromConst swfifc = {};
+
+// CIR: cir.global external @swfifc = #cir.zero : !rec_anon_struct
+// LLVM: @swfifc = global { i8, i8, i32 } zeroinitializer, align 4
+// OGCG: @swfifc = global { i8, i8, i32 } zeroinitializer, align 4
+
+StructWithFieldInitFromConst swfifc2 = { 2 };
+
+// CIR: cir.global external @swfifc2 = #cir.const_record<{#cir.int<2> : !u8i, #cir.int<0> : !u8i, #cir.int<2> : !s32i}> : !rec_anon_struct
+// LLVM: @swfifc2 = global { i8, i8, i32 } { i8 2, i8 0, i32 2 }, align 4
+// OGCG: @swfifc2 = global { i8, i8, i32 } { i8 2, i8 0, i32 2 }, align 4
+
 void init() {
   S s1 = {1, 2, 3};
   S s2 = {4, 5};