diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index b07f8e7f756..28d18918c74 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -676,7 +676,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			v_tmp_loaddata =
 				LLVMBuildPointerCast(b, v_attdatap, vartypep, "");
 			v_tmp_loaddata = l_load(b, vartype, v_tmp_loaddata, "attr_byval");
-			v_tmp_loaddata = LLVMBuildZExt(b, v_tmp_loaddata, TypeSizeT, "");
+			v_tmp_loaddata = LLVMBuildSExt(b, v_tmp_loaddata, TypeSizeT, "");
 
 			LLVMBuildStore(b, v_tmp_loaddata, v_resultp);
 		}