diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
index 33b6c12962c3..542171c39c7f 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -302,6 +302,678 @@ RValue CIRGenFunction::buildRotate(const CallExpr *E, bool IsRotateRight) {
   return RValue::get(r);
 }
 
+/// Get builtin name for unhandled BuiltinID in the function
+/// `CIRGenFunction::buildBuiltinExpr`. Thoese builtin names are handled
+/// in OG code `CodeGenFunction::EmitBuiltinExpr`.
+/// NOTE: Every time we implement handling of a case in
+/// the function `CIRGenFunction::buildBuiltinExpr`, it should be remove here.
+static std::string getUnhandledBuiltinName(unsigned builtinID) {
+  switch (builtinID) {
+  default:
+    return std::string();
+  case Builtin::BI__builtin_acos:
+    return "Builtin::BI__builtin_acos";
+  case Builtin::BI__builtin_acosf:
+    return "Builtin::BI__builtin_acosf";
+  case Builtin::BI__builtin_acosf16:
+    return "Builtin::BI__builtin_acosf16";
+  case Builtin::BI__builtin_acosl:
+    return "Builtin::BI__builtin_acosl";
+  case Builtin::BI__builtin_acosf128:
+    return "Builtin::BI__builtin_acosf128";
+  case Builtin::BI__builtin_asin:
+    return "Builtin::BI__builtin_asin";
+  case Builtin::BI__builtin_asinf:
+    return "Builtin::BI__builtin_asinf";
+  case Builtin::BI__builtin_asinf16:
+    return "Builtin::BI__builtin_asinf16";
+  case Builtin::BI__builtin_asinl:
+    return "Builtin::BI__builtin_asinl";
+  case Builtin::BI__builtin_asinf128:
+    return "Builtin::BI__builtin_asinf128";
+  case Builtin::BI__builtin_atan:
+    return "Builtin::BI__builtin_atan";
+  case Builtin::BI__builtin_atanf:
+    return "Builtin::BI__builtin_atanf";
+  case Builtin::BI__builtin_atanf16:
+    return "Builtin::BI__builtin_atanf16";
+  case Builtin::BI__builtin_atanl:
+    return "Builtin::BI__builtin_atanl";
+  case Builtin::BI__builtin_atanf128:
+    return "Builtin::BI__builtin_atanf128";
+  case Builtin::BI__builtin_cosh:
+    return "Builtin::BI__builtin_cosh";
+  case Builtin::BI__builtin_coshf:
+    return "Builtin::BI__builtin_coshf";
+  case Builtin::BI__builtin_coshf16:
+    return "Builtin::BI__builtin_coshf16";
+  case Builtin::BI__builtin_coshl:
+    return "Builtin::BI__builtin_coshl";
+  case Builtin::BI__builtin_coshf128:
+    return "Builtin::BI__builtin_coshf128";
+  case Builtin::BI__builtin_exp10:
+    return "Builtin::BI__builtin_exp10";
+  case Builtin::BI__builtin_exp10f:
+    return "Builtin::BI__builtin_exp10f";
+  case Builtin::BI__builtin_exp10f16:
+    return "Builtin::BI__builtin_exp10f16";
+  case Builtin::BI__builtin_exp10l:
+    return "Builtin::BI__builtin_exp10l";
+  case Builtin::BI__builtin_exp10f128:
+    return "Builtin::BI__builtin_exp10f128";
+  case Builtin::BI__builtin_elementwise_fmod:
+    return "Builtin::BI__builtin_elementwise_fmod";
+  case Builtin::BI__builtin_roundeven:
+    return "Builtin::BI__builtin_roundeven";
+  case Builtin::BI__builtin_roundevenf:
+    return "Builtin::BI__builtin_roundevenf";
+  case Builtin::BI__builtin_roundevenf16:
+    return "Builtin::BI__builtin_roundevenf16";
+  case Builtin::BI__builtin_roundevenl:
+    return "Builtin::BI__builtin_roundevenl";
+  case Builtin::BI__builtin_roundevenf128:
+    return "Builtin::BI__builtin_roundevenf128";
+  case Builtin::BI__builtin_sinh:
+    return "Builtin::BI__builtin_sinh";
+  case Builtin::BI__builtin_sinhf:
+    return "Builtin::BI__builtin_sinhf";
+  case Builtin::BI__builtin_sinhf16:
+    return "Builtin::BI__builtin_sinhf16";
+  case Builtin::BI__builtin_sinhl:
+    return "Builtin::BI__builtin_sinhl";
+  case Builtin::BI__builtin_sinhf128:
+    return "Builtin::BI__builtin_sinhf128";
+  case Builtin::BI__builtin_elementwise_sqrt:
+    return "Builtin::BI__builtin_elementwise_sqrt";
+  case Builtin::BI__builtin_tan:
+    return "Builtin::BI__builtin_tan";
+  case Builtin::BI__builtin_tanf:
+    return "Builtin::BI__builtin_tanf";
+  case Builtin::BI__builtin_tanf16:
+    return "Builtin::BI__builtin_tanf16";
+  case Builtin::BI__builtin_tanl:
+    return "Builtin::BI__builtin_tanl";
+  case Builtin::BI__builtin_tanf128:
+    return "Builtin::BI__builtin_tanf128";
+  case Builtin::BI__builtin_tanh:
+    return "Builtin::BI__builtin_tanh";
+  case Builtin::BI__builtin_tanhf:
+    return "Builtin::BI__builtin_tanhf";
+  case Builtin::BI__builtin_tanhf16:
+    return "Builtin::BI__builtin_tanhf16";
+  case Builtin::BI__builtin_tanhl:
+    return "Builtin::BI__builtin_tanhl";
+  case Builtin::BI__builtin_tanhf128:
+    return "Builtin::BI__builtin_tanhf128";
+  case Builtin::BI__builtin_ldexp:
+    return "Builtin::BI__builtin_ldexp";
+  case Builtin::BI__builtin_ldexpf:
+    return "Builtin::BI__builtin_ldexpf";
+  case Builtin::BI__builtin_ldexpl:
+    return "Builtin::BI__builtin_ldexpl";
+  case Builtin::BI__builtin_ldexpf16:
+    return "Builtin::BI__builtin_ldexpf16";
+  case Builtin::BI__builtin_ldexpf128:
+    return "Builtin::BI__builtin_ldexpf128";
+  case Builtin::BI__builtin_abs:
+    return "Builtin::BI__builtin_abs";
+  case Builtin::BI__builtin_labs:
+    return "Builtin::BI__builtin_labs";
+  case Builtin::BI__builtin_llabs:
+    return "Builtin::BI__builtin_llabs";
+  case Builtin::BI__builtin_preserve_access_index:
+    return "Builtin::BI__builtin_preserve_access_index";
+  case Builtin::BI__lzcnt16:
+    return "Builtin::BI__lzcnt16";
+  case Builtin::BI__lzcnt:
+    return "Builtin::BI__lzcnt";
+  case Builtin::BI__lzcnt64:
+    return "Builtin::BI__lzcnt64";
+  case Builtin::BI__builtin_allow_runtime_check:
+    return "Builtin::BI__builtin_allow_runtime_check";
+  case Builtin::BI__arithmetic_fence:
+    return "Builtin::BI__arithmetic_fence";
+  case Builtin::BI__builtin_bitreverse8:
+    return "Builtin::BI__builtin_bitreverse8";
+  case Builtin::BI__builtin_bitreverse16:
+    return "Builtin::BI__builtin_bitreverse16";
+  case Builtin::BI__builtin_bitreverse32:
+    return "Builtin::BI__builtin_bitreverse32";
+  case Builtin::BI__builtin_bitreverse64:
+    return "Builtin::BI__builtin_bitreverse64";
+  case Builtin::BI__builtin_readcyclecounter:
+    return "Builtin::BI__builtin_readcyclecounter";
+  case Builtin::BI__builtin_readsteadycounter:
+    return "Builtin::BI__builtin_readsteadycounter";
+  case Builtin::BI__builtin_verbose_trap:
+    return "Builtin::BI__builtin_verbose_trap";
+  case Builtin::BI__debugbreak:
+    return "Builtin::BI__debugbreak";
+  case Builtin::BI__builtin_powi:
+    return "Builtin::BI__builtin_powi";
+  case Builtin::BI__builtin_powif:
+    return "Builtin::BI__builtin_powif";
+  case Builtin::BI__builtin_powil:
+    return "Builtin::BI__builtin_powil";
+  case Builtin::BI__builtin_frexpl:
+    return "Builtin::BI__builtin_frexpl";
+  case Builtin::BI__builtin_frexp:
+    return "Builtin::BI__builtin_frexp";
+  case Builtin::BI__builtin_frexpf:
+    return "Builtin::BI__builtin_frexpf";
+  case Builtin::BI__builtin_frexpf128:
+    return "Builtin::BI__builtin_frexpf128";
+  case Builtin::BI__builtin_frexpf16:
+    return "Builtin::BI__builtin_frexpf16";
+  case Builtin::BI__builtin_isgreater:
+    return "Builtin::BI__builtin_isgreater";
+  case Builtin::BI__builtin_isgreaterequal:
+    return "Builtin::BI__builtin_isgreaterequal";
+  case Builtin::BI__builtin_isless:
+    return "Builtin::BI__builtin_isless";
+  case Builtin::BI__builtin_islessequal:
+    return "Builtin::BI__builtin_islessequal";
+  case Builtin::BI__builtin_islessgreater:
+    return "Builtin::BI__builtin_islessgreater";
+  case Builtin::BI__builtin_isunordered:
+    return "Builtin::BI__builtin_isunordered";
+  case Builtin::BI__builtin_isnan:
+    return "Builtin::BI__builtin_isnan";
+  case Builtin::BI__builtin_issignaling:
+    return "Builtin::BI__builtin_issignaling";
+  case Builtin::BI__builtin_isinf:
+    return "Builtin::BI__builtin_isinf";
+  case Builtin::BI__finite:
+    return "Builtin::BI__finite";
+  case Builtin::BI__finitef:
+    return "Builtin::BI__finitef";
+  case Builtin::BI__finitel:
+    return "Builtin::BI__finitel";
+  case Builtin::BI__builtin_isfinite:
+    return "Builtin::BI__builtin_isfinite";
+  case Builtin::BI__builtin_isnormal:
+    return "Builtin::BI__builtin_isnormal";
+  case Builtin::BI__builtin_issubnormal:
+    return "Builtin::BI__builtin_issubnormal";
+  case Builtin::BI__builtin_iszero:
+    return "Builtin::BI__builtin_iszero";
+  case Builtin::BI__builtin_isfpclass:
+    return "Builtin::BI__builtin_isfpclass";
+  case Builtin::BI__builtin_nondeterministic_value:
+    return "Builtin::BI__builtin_nondeterministic_value";
+  case Builtin::BI__builtin_elementwise_abs:
+    return "Builtin::BI__builtin_elementwise_abs";
+  case Builtin::BI__builtin_elementwise_acos:
+    return "Builtin::BI__builtin_elementwise_acos";
+  case Builtin::BI__builtin_elementwise_asin:
+    return "Builtin::BI__builtin_elementwise_asin";
+  case Builtin::BI__builtin_elementwise_atan:
+    return "Builtin::BI__builtin_elementwise_atan";
+  case Builtin::BI__builtin_elementwise_atan2:
+    return "Builtin::BI__builtin_elementwise_atan2";
+  case Builtin::BI__builtin_elementwise_ceil:
+    return "Builtin::BI__builtin_elementwise_ceil";
+  case Builtin::BI__builtin_elementwise_exp:
+    return "Builtin::BI__builtin_elementwise_exp";
+  case Builtin::BI__builtin_elementwise_exp2:
+    return "Builtin::BI__builtin_elementwise_exp2";
+  case Builtin::BI__builtin_elementwise_log:
+    return "Builtin::BI__builtin_elementwise_log";
+  case Builtin::BI__builtin_elementwise_log2:
+    return "Builtin::BI__builtin_elementwise_log2";
+  case Builtin::BI__builtin_elementwise_log10:
+    return "Builtin::BI__builtin_elementwise_log10";
+  case Builtin::BI__builtin_elementwise_pow:
+    return "Builtin::BI__builtin_elementwise_pow";
+  case Builtin::BI__builtin_elementwise_bitreverse:
+    return "Builtin::BI__builtin_elementwise_bitreverse";
+  case Builtin::BI__builtin_elementwise_cos:
+    return "Builtin::BI__builtin_elementwise_cos";
+  case Builtin::BI__builtin_elementwise_cosh:
+    return "Builtin::BI__builtin_elementwise_cosh";
+  case Builtin::BI__builtin_elementwise_floor:
+    return "Builtin::BI__builtin_elementwise_floor";
+  case Builtin::BI__builtin_elementwise_popcount:
+    return "Builtin::BI__builtin_elementwise_popcount";
+  case Builtin::BI__builtin_elementwise_roundeven:
+    return "Builtin::BI__builtin_elementwise_roundeven";
+  case Builtin::BI__builtin_elementwise_round:
+    return "Builtin::BI__builtin_elementwise_round";
+  case Builtin::BI__builtin_elementwise_rint:
+    return "Builtin::BI__builtin_elementwise_rint";
+  case Builtin::BI__builtin_elementwise_nearbyint:
+    return "Builtin::BI__builtin_elementwise_nearbyint";
+  case Builtin::BI__builtin_elementwise_sin:
+    return "Builtin::BI__builtin_elementwise_sin";
+  case Builtin::BI__builtin_elementwise_sinh:
+    return "Builtin::BI__builtin_elementwise_sinh";
+  case Builtin::BI__builtin_elementwise_tan:
+    return "Builtin::BI__builtin_elementwise_tan";
+  case Builtin::BI__builtin_elementwise_tanh:
+    return "Builtin::BI__builtin_elementwise_tanh";
+  case Builtin::BI__builtin_elementwise_trunc:
+    return "Builtin::BI__builtin_elementwise_trunc";
+  case Builtin::BI__builtin_elementwise_canonicalize:
+    return "Builtin::BI__builtin_elementwise_canonicalize";
+  case Builtin::BI__builtin_elementwise_copysign:
+    return "Builtin::BI__builtin_elementwise_copysign";
+  case Builtin::BI__builtin_elementwise_fma:
+    return "Builtin::BI__builtin_elementwise_fma";
+  case Builtin::BI__builtin_elementwise_add_sat:
+    return "Builtin::BI__builtin_elementwise_add_sat";
+  case Builtin::BI__builtin_elementwise_sub_sat:
+    return "Builtin::BI__builtin_elementwise_sub_sat";
+  case Builtin::BI__builtin_elementwise_max:
+    return "Builtin::BI__builtin_elementwise_max";
+  case Builtin::BI__builtin_elementwise_min:
+    return "Builtin::BI__builtin_elementwise_min";
+  case Builtin::BI__builtin_elementwise_maximum:
+    return "Builtin::BI__builtin_elementwise_maximum";
+  case Builtin::BI__builtin_elementwise_minimum:
+    return "Builtin::BI__builtin_elementwise_minimum";
+  case Builtin::BI__builtin_reduce_max:
+    return "Builtin::BI__builtin_reduce_max";
+  case Builtin::BI__builtin_reduce_min:
+    return "Builtin::BI__builtin_reduce_min";
+  case Builtin::BI__builtin_reduce_add:
+    return "Builtin::BI__builtin_reduce_add";
+  case Builtin::BI__builtin_reduce_mul:
+    return "Builtin::BI__builtin_reduce_mul";
+  case Builtin::BI__builtin_reduce_xor:
+    return "Builtin::BI__builtin_reduce_xor";
+  case Builtin::BI__builtin_reduce_or:
+    return "Builtin::BI__builtin_reduce_or";
+  case Builtin::BI__builtin_reduce_and:
+    return "Builtin::BI__builtin_reduce_and";
+  case Builtin::BI__builtin_reduce_maximum:
+    return "Builtin::BI__builtin_reduce_maximum";
+  case Builtin::BI__builtin_reduce_minimum:
+    return "Builtin::BI__builtin_reduce_minimum";
+  case Builtin::BI__builtin_matrix_transpose:
+    return "Builtin::BI__builtin_matrix_transpose";
+  case Builtin::BI__builtin_matrix_column_major_load:
+    return "Builtin::BI__builtin_matrix_column_major_load";
+  case Builtin::BI__builtin_matrix_column_major_store:
+    return "Builtin::BI__builtin_matrix_column_major_store";
+  case Builtin::BI__builtin_isinf_sign:
+    return "Builtin::BI__builtin_isinf_sign";
+  case Builtin::BI__builtin_flt_rounds:
+    return "Builtin::BI__builtin_flt_rounds";
+  case Builtin::BI__builtin_set_flt_rounds:
+    return "Builtin::BI__builtin_set_flt_rounds";
+  case Builtin::BI__builtin_fpclassify:
+    return "Builtin::BI__builtin_fpclassify";
+  case Builtin::BI__builtin_alloca_with_align_uninitialized:
+    return "Builtin::BI__builtin_alloca_with_align_uninitialized";
+  case Builtin::BI__builtin_alloca_with_align:
+    return "Builtin::BI__builtin_alloca_with_align";
+  case Builtin::BI__builtin_bzero:
+    return "Builtin::BI__builtin_bzero";
+  case Builtin::BI__builtin_bcopy:
+    return "Builtin::BI__builtin_bcopy";
+  case Builtin::BI__builtin_memcpy_inline:
+    return "Builtin::BI__builtin_memcpy_inline";
+  case Builtin::BI__builtin_char_memchr:
+    return "Builtin::BI__builtin_char_memchr";
+  case Builtin::BI__builtin___memcpy_chk:
+    return "Builtin::BI__builtin___memcpy_chk";
+  case Builtin::BI__builtin_objc_memmove_collectable:
+    return "Builtin::BI__builtin_objc_memmove_collectable";
+  case Builtin::BI__builtin___memmove_chk:
+    return "Builtin::BI__builtin___memmove_chk";
+  case Builtin::BI__builtin_memmove:
+    return "Builtin::BI__builtin_memmove";
+  case Builtin::BI__builtin_memset:
+    return "Builtin::BI__builtin_memset";
+  case Builtin::BI__builtin_memset_inline:
+    return "Builtin::BI__builtin_memset_inline";
+  case Builtin::BI__builtin___memset_chk:
+    return "Builtin::BI__builtin___memset_chk";
+  case Builtin::BI__builtin_wmemchr:
+    return "Builtin::BI__builtin_wmemchr";
+  case Builtin::BI__builtin_wmemcmp:
+    return "Builtin::BI__builtin_wmemcmp";
+  case Builtin::BI__builtin_dwarf_cfa:
+    return "Builtin::BI__builtin_dwarf_cfa";
+  case Builtin::BI__builtin_return_address:
+    return "Builtin::BI__builtin_return_address";
+  case Builtin::BI__builtin_frame_address:
+    return "Builtin::BI__builtin_frame_address";
+  case Builtin::BI__builtin_extract_return_addr:
+    return "Builtin::BI__builtin_extract_return_addr";
+  case Builtin::BI__builtin_frob_return_addr:
+    return "Builtin::BI__builtin_frob_return_addr";
+  case Builtin::BI__builtin_dwarf_sp_column:
+    return "Builtin::BI__builtin_dwarf_sp_column";
+  case Builtin::BI__builtin_init_dwarf_reg_size_table:
+    return "Builtin::BI__builtin_init_dwarf_reg_size_table";
+  case Builtin::BI__builtin_eh_return:
+    return "Builtin::BI__builtin_eh_return";
+  case Builtin::BI__builtin_unwind_init:
+    return "Builtin::BI__builtin_unwind_init";
+  case Builtin::BI__builtin_extend_pointer:
+    return "Builtin::BI__builtin_extend_pointer";
+  case Builtin::BI__builtin_setjmp:
+    return "Builtin::BI__builtin_setjmp";
+  case Builtin::BI__builtin_longjmp:
+    return "Builtin::BI__builtin_longjmp";
+  case Builtin::BI__builtin_launder:
+    return "Builtin::BI__builtin_launder";
+  case Builtin::BI__sync_fetch_and_or:
+    return "Builtin::BI__sync_fetch_and_or";
+  case Builtin::BI__sync_fetch_and_and:
+    return "Builtin::BI__sync_fetch_and_and";
+  case Builtin::BI__sync_fetch_and_xor:
+    return "Builtin::BI__sync_fetch_and_xor";
+  case Builtin::BI__sync_fetch_and_nand:
+    return "Builtin::BI__sync_fetch_and_nand";
+  case Builtin::BI__sync_add_and_fetch:
+    return "Builtin::BI__sync_add_and_fetch";
+  case Builtin::BI__sync_sub_and_fetch:
+    return "Builtin::BI__sync_sub_and_fetch";
+  case Builtin::BI__sync_and_and_fetch:
+    return "Builtin::BI__sync_and_and_fetch";
+  case Builtin::BI__sync_or_and_fetch:
+    return "Builtin::BI__sync_or_and_fetch";
+  case Builtin::BI__sync_xor_and_fetch:
+    return "Builtin::BI__sync_xor_and_fetch";
+  case Builtin::BI__sync_nand_and_fetch:
+    return "Builtin::BI__sync_nand_and_fetch";
+  case Builtin::BI__sync_val_compare_and_swap:
+    return "Builtin::BI__sync_val_compare_and_swap";
+  case Builtin::BI__sync_bool_compare_and_swap:
+    return "Builtin::BI__sync_bool_compare_and_swap";
+  case Builtin::BI__sync_lock_test_and_set:
+    return "Builtin::BI__sync_lock_test_and_set";
+  case Builtin::BI__sync_lock_release:
+    return "Builtin::BI__sync_lock_release";
+  case Builtin::BI__sync_swap:
+    return "Builtin::BI__sync_swap";
+  case Builtin::BI__sync_fetch_and_or_1:
+    return "Builtin::BI__sync_fetch_and_or_1";
+  case Builtin::BI__sync_fetch_and_or_2:
+    return "Builtin::BI__sync_fetch_and_or_2";
+  case Builtin::BI__sync_fetch_and_or_4:
+    return "Builtin::BI__sync_fetch_and_or_4";
+  case Builtin::BI__sync_fetch_and_or_8:
+    return "Builtin::BI__sync_fetch_and_or_8";
+  case Builtin::BI__sync_fetch_and_or_16:
+    return "Builtin::BI__sync_fetch_and_or_16";
+  case Builtin::BI__sync_fetch_and_and_1:
+    return "Builtin::BI__sync_fetch_and_and_1";
+  case Builtin::BI__sync_fetch_and_and_2:
+    return "Builtin::BI__sync_fetch_and_and_2";
+  case Builtin::BI__sync_fetch_and_and_4:
+    return "Builtin::BI__sync_fetch_and_and_4";
+  case Builtin::BI__sync_fetch_and_and_8:
+    return "Builtin::BI__sync_fetch_and_and_8";
+  case Builtin::BI__sync_fetch_and_and_16:
+    return "Builtin::BI__sync_fetch_and_and_16";
+  case Builtin::BI__sync_fetch_and_xor_1:
+    return "Builtin::BI__sync_fetch_and_xor_1";
+  case Builtin::BI__sync_fetch_and_xor_2:
+    return "Builtin::BI__sync_fetch_and_xor_2";
+  case Builtin::BI__sync_fetch_and_xor_4:
+    return "Builtin::BI__sync_fetch_and_xor_4";
+  case Builtin::BI__sync_fetch_and_xor_8:
+    return "Builtin::BI__sync_fetch_and_xor_8";
+  case Builtin::BI__sync_fetch_and_xor_16:
+    return "Builtin::BI__sync_fetch_and_xor_16";
+  case Builtin::BI__sync_fetch_and_nand_1:
+    return "Builtin::BI__sync_fetch_and_nand_1";
+  case Builtin::BI__sync_fetch_and_nand_2:
+    return "Builtin::BI__sync_fetch_and_nand_2";
+  case Builtin::BI__sync_fetch_and_nand_4:
+    return "Builtin::BI__sync_fetch_and_nand_4";
+  case Builtin::BI__sync_fetch_and_nand_8:
+    return "Builtin::BI__sync_fetch_and_nand_8";
+  case Builtin::BI__sync_fetch_and_nand_16:
+    return "Builtin::BI__sync_fetch_and_nand_16";
+  case Builtin::BI__sync_fetch_and_min:
+    return "Builtin::BI__sync_fetch_and_min";
+  case Builtin::BI__sync_fetch_and_max:
+    return "Builtin::BI__sync_fetch_and_max";
+  case Builtin::BI__sync_fetch_and_umin:
+    return "Builtin::BI__sync_fetch_and_umin";
+  case Builtin::BI__sync_fetch_and_umax:
+    return "Builtin::BI__sync_fetch_and_umax";
+  case Builtin::BI__sync_add_and_fetch_1:
+    return "Builtin::BI__sync_add_and_fetch_1";
+  case Builtin::BI__sync_add_and_fetch_2:
+    return "Builtin::BI__sync_add_and_fetch_2";
+  case Builtin::BI__sync_add_and_fetch_4:
+    return "Builtin::BI__sync_add_and_fetch_4";
+  case Builtin::BI__sync_add_and_fetch_8:
+    return "Builtin::BI__sync_add_and_fetch_8";
+  case Builtin::BI__sync_add_and_fetch_16:
+    return "Builtin::BI__sync_add_and_fetch_16";
+  case Builtin::BI__sync_sub_and_fetch_1:
+    return "Builtin::BI__sync_sub_and_fetch_1";
+  case Builtin::BI__sync_sub_and_fetch_2:
+    return "Builtin::BI__sync_sub_and_fetch_2";
+  case Builtin::BI__sync_sub_and_fetch_4:
+    return "Builtin::BI__sync_sub_and_fetch_4";
+  case Builtin::BI__sync_sub_and_fetch_8:
+    return "Builtin::BI__sync_sub_and_fetch_8";
+  case Builtin::BI__sync_sub_and_fetch_16:
+    return "Builtin::BI__sync_sub_and_fetch_16";
+  case Builtin::BI__sync_and_and_fetch_1:
+    return "Builtin::BI__sync_and_and_fetch_1";
+  case Builtin::BI__sync_and_and_fetch_2:
+    return "Builtin::BI__sync_and_and_fetch_2";
+  case Builtin::BI__sync_and_and_fetch_4:
+    return "Builtin::BI__sync_and_and_fetch_4";
+  case Builtin::BI__sync_and_and_fetch_8:
+    return "Builtin::BI__sync_and_and_fetch_8";
+  case Builtin::BI__sync_and_and_fetch_16:
+    return "Builtin::BI__sync_and_and_fetch_16";
+  case Builtin::BI__sync_or_and_fetch_1:
+    return "Builtin::BI__sync_or_and_fetch_1";
+  case Builtin::BI__sync_or_and_fetch_2:
+    return "Builtin::BI__sync_or_and_fetch_2";
+  case Builtin::BI__sync_or_and_fetch_4:
+    return "Builtin::BI__sync_or_and_fetch_4";
+  case Builtin::BI__sync_or_and_fetch_8:
+    return "Builtin::BI__sync_or_and_fetch_8";
+  case Builtin::BI__sync_or_and_fetch_16:
+    return "Builtin::BI__sync_or_and_fetch_16";
+  case Builtin::BI__sync_xor_and_fetch_1:
+    return "Builtin::BI__sync_xor_and_fetch_1";
+  case Builtin::BI__sync_xor_and_fetch_2:
+    return "Builtin::BI__sync_xor_and_fetch_2";
+  case Builtin::BI__sync_xor_and_fetch_4:
+    return "Builtin::BI__sync_xor_and_fetch_4";
+  case Builtin::BI__sync_xor_and_fetch_8:
+    return "Builtin::BI__sync_xor_and_fetch_8";
+  case Builtin::BI__sync_xor_and_fetch_16:
+    return "Builtin::BI__sync_xor_and_fetch_16";
+  case Builtin::BI__sync_nand_and_fetch_1:
+    return "Builtin::BI__sync_nand_and_fetch_1";
+  case Builtin::BI__sync_nand_and_fetch_2:
+    return "Builtin::BI__sync_nand_and_fetch_2";
+  case Builtin::BI__sync_nand_and_fetch_4:
+    return "Builtin::BI__sync_nand_and_fetch_4";
+  case Builtin::BI__sync_nand_and_fetch_8:
+    return "Builtin::BI__sync_nand_and_fetch_8";
+  case Builtin::BI__sync_nand_and_fetch_16:
+    return "Builtin::BI__sync_nand_and_fetch_16";
+  case Builtin::BI__sync_swap_1:
+    return "Builtin::BI__sync_swap_1";
+  case Builtin::BI__sync_swap_2:
+    return "Builtin::BI__sync_swap_2";
+  case Builtin::BI__sync_swap_4:
+    return "Builtin::BI__sync_swap_4";
+  case Builtin::BI__sync_swap_8:
+    return "Builtin::BI__sync_swap_8";
+  case Builtin::BI__sync_swap_16:
+    return "Builtin::BI__sync_swap_16";
+  case Builtin::BI__sync_lock_test_and_set_1:
+    return "Builtin::BI__sync_lock_test_and_set_1";
+  case Builtin::BI__sync_lock_test_and_set_2:
+    return "Builtin::BI__sync_lock_test_and_set_2";
+  case Builtin::BI__sync_lock_test_and_set_4:
+    return "Builtin::BI__sync_lock_test_and_set_4";
+  case Builtin::BI__sync_lock_test_and_set_8:
+    return "Builtin::BI__sync_lock_test_and_set_8";
+  case Builtin::BI__sync_lock_test_and_set_16:
+    return "Builtin::BI__sync_lock_test_and_set_16";
+  case Builtin::BI__sync_lock_release_1:
+    return "Builtin::BI__sync_lock_release_1";
+  case Builtin::BI__sync_lock_release_2:
+    return "Builtin::BI__sync_lock_release_2";
+  case Builtin::BI__sync_lock_release_4:
+    return "Builtin::BI__sync_lock_release_4";
+  case Builtin::BI__sync_lock_release_8:
+    return "Builtin::BI__sync_lock_release_8";
+  case Builtin::BI__sync_lock_release_16:
+    return "Builtin::BI__sync_lock_release_16";
+  case Builtin::BI__sync_synchronize:
+    return "Builtin::BI__sync_synchronize";
+  case Builtin::BI__builtin_nontemporal_load:
+    return "Builtin::BI__builtin_nontemporal_load";
+  case Builtin::BI__builtin_nontemporal_store:
+    return "Builtin::BI__builtin_nontemporal_store";
+  case Builtin::BI__c11_atomic_is_lock_free:
+    return "Builtin::BI__c11_atomic_is_lock_free";
+  case Builtin::BI__atomic_is_lock_free:
+    return "Builtin::BI__atomic_is_lock_free";
+  case Builtin::BI__atomic_test_and_set:
+    return "Builtin::BI__atomic_test_and_set";
+  case Builtin::BI__atomic_clear:
+    return "Builtin::BI__atomic_clear";
+  case Builtin::BI__atomic_thread_fence:
+    return "Builtin::BI__atomic_thread_fence";
+  case Builtin::BI__atomic_signal_fence:
+    return "Builtin::BI__atomic_signal_fence";
+  case Builtin::BI__c11_atomic_thread_fence:
+    return "Builtin::BI__c11_atomic_thread_fence";
+  case Builtin::BI__c11_atomic_signal_fence:
+    return "Builtin::BI__c11_atomic_signal_fence";
+  case Builtin::BI__builtin_signbit:
+    return "Builtin::BI__builtin_signbit";
+  case Builtin::BI__builtin_signbitf:
+    return "Builtin::BI__builtin_signbitf";
+  case Builtin::BI__builtin_signbitl:
+    return "Builtin::BI__builtin_signbitl";
+  case Builtin::BI__warn_memset_zero_len:
+    return "Builtin::BI__warn_memset_zero_len";
+  case Builtin::BI__annotation:
+    return "Builtin::BI__annotation";
+  case Builtin::BI__builtin_annotation:
+    return "Builtin::BI__builtin_annotation";
+  case Builtin::BI__builtin_addcb:
+    return "Builtin::BI__builtin_addcb";
+  case Builtin::BI__builtin_addcs:
+    return "Builtin::BI__builtin_addcs";
+  case Builtin::BI__builtin_addc:
+    return "Builtin::BI__builtin_addc";
+  case Builtin::BI__builtin_addcl:
+    return "Builtin::BI__builtin_addcl";
+  case Builtin::BI__builtin_addcll:
+    return "Builtin::BI__builtin_addcll";
+  case Builtin::BI__builtin_subcb:
+    return "Builtin::BI__builtin_subcb";
+  case Builtin::BI__builtin_subcs:
+    return "Builtin::BI__builtin_subcs";
+  case Builtin::BI__builtin_subc:
+    return "Builtin::BI__builtin_subc";
+  case Builtin::BI__builtin_subcl:
+    return "Builtin::BI__builtin_subcl";
+  case Builtin::BI__builtin_subcll:
+    return "Builtin::BI__builtin_subcll";
+  case Builtin::BI__addressof:
+    return "Builtin::BI__addressof";
+  case Builtin::BI__builtin_addressof:
+    return "Builtin::BI__builtin_addressof";
+  case Builtin::BI__builtin_function_start:
+    return "Builtin::BI__builtin_function_start";
+  case Builtin::BI__builtin_operator_new:
+    return "Builtin::BI__builtin_operator_new";
+  case Builtin::BI__builtin_operator_delete:
+    return "Builtin::BI__builtin_operator_delete";
+  case Builtin::BI__builtin_is_aligned:
+    return "Builtin::BI__builtin_is_aligned";
+  case Builtin::BI__builtin_align_up:
+    return "Builtin::BI__builtin_align_up";
+  case Builtin::BI__builtin_align_down:
+    return "Builtin::BI__builtin_align_down";
+  case Builtin::BI__noop:
+    return "Builtin::BI__noop";
+  case Builtin::BI__builtin_call_with_static_chain:
+    return "Builtin::BI__builtin_call_with_static_chain";
+  case Builtin::BI__iso_volatile_load8:
+    return "Builtin::BI__iso_volatile_load8";
+  case Builtin::BI__iso_volatile_load16:
+    return "Builtin::BI__iso_volatile_load16";
+  case Builtin::BI__iso_volatile_load32:
+    return "Builtin::BI__iso_volatile_load32";
+  case Builtin::BI__iso_volatile_load64:
+    return "Builtin::BI__iso_volatile_load64";
+  case Builtin::BI__iso_volatile_store8:
+    return "Builtin::BI__iso_volatile_store8";
+  case Builtin::BI__iso_volatile_store16:
+    return "Builtin::BI__iso_volatile_store16";
+  case Builtin::BI__iso_volatile_store32:
+    return "Builtin::BI__iso_volatile_store32";
+  case Builtin::BI__iso_volatile_store64:
+    return "Builtin::BI__iso_volatile_store64";
+  case Builtin::BI__builtin_ptrauth_sign_constant:
+    return "Builtin::BI__builtin_ptrauth_sign_constant";
+  case Builtin::BI__builtin_ptrauth_auth:
+    return "Builtin::BI__builtin_ptrauth_auth";
+  case Builtin::BI__builtin_ptrauth_auth_and_resign:
+    return "Builtin::BI__builtin_ptrauth_auth_and_resign";
+  case Builtin::BI__builtin_ptrauth_blend_discriminator:
+    return "Builtin::BI__builtin_ptrauth_blend_discriminator";
+  case Builtin::BI__builtin_ptrauth_sign_generic_data:
+    return "Builtin::BI__builtin_ptrauth_sign_generic_data";
+  case Builtin::BI__builtin_ptrauth_sign_unauthenticated:
+    return "Builtin::BI__builtin_ptrauth_sign_unauthenticated";
+  case Builtin::BI__builtin_ptrauth_strip:
+    return "Builtin::BI__builtin_ptrauth_strip";
+  case Builtin::BI__exception_code:
+    return "Builtin::BI__exception_code";
+  case Builtin::BI__exception_info:
+    return "Builtin::BI__exception_info";
+  case Builtin::BI__abnormal_termination:
+    return "Builtin::BI__abnormal_termination";
+  case Builtin::BI__builtin_store_half:
+    return "Builtin::BI__builtin_store_half";
+  case Builtin::BI__builtin_store_halff:
+    return "Builtin::BI__builtin_store_halff";
+  case Builtin::BI__builtin_load_half:
+    return "Builtin::BI__builtin_load_half";
+  case Builtin::BI__builtin_load_halff:
+    return "Builtin::BI__builtin_load_halff";
+  case Builtin::BI__builtin_printf:
+    return "Builtin::BI__builtin_printf";
+  case Builtin::BI__builtin_canonicalize:
+    return "Builtin::BI__builtin_canonicalize";
+  case Builtin::BI__builtin_canonicalizef:
+    return "Builtin::BI__builtin_canonicalizef";
+  case Builtin::BI__builtin_canonicalizef16:
+    return "Builtin::BI__builtin_canonicalizef16";
+  case Builtin::BI__builtin_canonicalizel:
+    return "Builtin::BI__builtin_canonicalizel";
+  case Builtin::BI__builtin_thread_pointer:
+    return "Builtin::BI__builtin_thread_pointer";
+  case Builtin::BI__builtin_os_log_format:
+    return "Builtin::BI__builtin_os_log_format";
+  case Builtin::BI__xray_customevent:
+    return "Builtin::BI__xray_customevent";
+  case Builtin::BI__xray_typedevent:
+    return "Builtin::BI__xray_typedevent";
+  case Builtin::BI__builtin_ms_va_start:
+    return "Builtin::BI__builtin_ms_va_start";
+  case Builtin::BI__builtin_ms_va_end:
+    return "Builtin::BI__builtin_ms_va_end";
+  case Builtin::BI__builtin_ms_va_copy:
+    return "Builtin::BI__builtin_ms_va_copy";
+  case Builtin::BI__builtin_get_device_side_mangled_name:
+    return "Builtin::BI__builtin_get_device_side_mangled_name";
+  }
+}
+
 RValue CIRGenFunction::buildBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
                                         const CallExpr *E,
                                         ReturnValueSlot ReturnValue) {
@@ -1343,6 +2015,16 @@ RValue CIRGenFunction::buildBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
   }
   }
 
+  // If a Builtin is not handled in above code but handled in original
+  // clang codegen, we will assert here with its name.
+  // It would be confusing and bad for triaging to let it go on
+  // as they will fail evetunally with unrelated message.
+  std::string unhandledName = getUnhandledBuiltinName(BuiltinID);
+  if (!unhandledName.empty()) {
+    llvm::errs() << unhandledName << " ";
+    llvm_unreachable("NYI");
+  }
+
   // If this is an alias for a lib function (e.g. __builtin_sin), emit
   // the call using the normal call path, but using the unmangled
   // version of the function name.