[clang] [clang][ASTImporter] Support Importer of BuiltinBitCastExpr (PR #74813)

[Balázs Kéri via cfe-commits]

================
@@ -9284,6 +9284,24 @@ TEST_P(ASTImporterOptionSpecificTestBase,
   // EXPECT_EQ(ToF1Imported->getPreviousDecl(), ToF1);
 }
 
+const internal::VariadicDynCastAllOfMatcher<Stmt, BuiltinBitCastExpr>
+    builtinBitCastExpr;
+
+TEST_P(ASTImporterOptionSpecificTestBase, ImportBuiltinBitCastExpr) {
+  const char *CodeFrom =
+      R"(
+      void foo(int T) { (void)__builtin_bit_cast(float, T); }
+      )";
+  Decl *FromTU = getTuDecl(CodeFrom, Lang_CXX20);
+  auto *FromFoo = FirstDeclMatcher<FunctionDecl>().match(
+      FromTU, functionDecl(hasName("foo")));
+  auto *ToFoo = Import(FromFoo, Lang_CXX20);
+  EXPECT_TRUE(ToFoo);
+  auto *ToBuiltinBitCastExpr =
+      FirstDeclMatcher<BuiltinBitCastExpr>().match(ToFoo, builtinBitCastExpr());
+  EXPECT_TRUE(ToBuiltinBitCastExpr);
+}
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balazske wrote:

Instead of this test a more simple test can be added in the `ImportExpr` section of **ASTImporterTest.cpp**.

https://github.com/llvm/llvm-project/pull/74813