Introduce --null-mod-by-zero config flag.

omniscidb/ConfigBuilder/ConfigBuilder.cpp

@@ -285,6 +285,12 @@ bool ConfigBuilder::parseCommandLineArgs(int argc,
           ->default_value(config_->exec.codegen.inf_div_by_zero)
           ->implicit_value(true),
       "Return INF on fp division by zero instead of throwing an exception.");
+  opt_desc.add_options()(
+      "null-mod-by-zero",
+      po::value<bool>(&config_->exec.codegen.null_mod_by_zero)
+          ->default_value(config_->exec.codegen.null_mod_by_zero)
+          ->implicit_value(true),
+      "Return NULL on modulo by zero instead of throwing an exception.");
   opt_desc.add_options()("enable-hoist-literals",
                          po::value<bool>(&config_->exec.codegen.hoist_literals)
                              ->default_value(config_->exec.codegen.hoist_literals)

omniscidb/QueryEngine/ArithmeticIR.cpp

@@ -622,9 +622,23 @@ llvm::Value* CodeGenerator::codegenMod(llvm::Value* lhs_lv,
                  : cgen_state_->emitCall(
                        "mod_" + null_typename + null_check_suffix,
                        {lhs_lv, rhs_lv, cgen_state_->llInt(inline_int_null_value(type))});
-  cgen_state_->ir_builder_.SetInsertPoint(mod_zero);
-  cgen_state_->ir_builder_.CreateRet(cgen_state_->llInt(Executor::ERR_DIV_BY_ZERO));
-  cgen_state_->ir_builder_.SetInsertPoint(mod_ok);
+  if (config_.exec.codegen.null_mod_by_zero) {
+    auto mod_res = llvm::BasicBlock::Create(
+        cgen_state_->context_, "mod_res", cgen_state_->current_func_);
+    cgen_state_->ir_builder_.CreateBr(mod_res);
+    cgen_state_->ir_builder_.SetInsertPoint(mod_zero);
+    cgen_state_->ir_builder_.CreateBr(mod_res);
+    cgen_state_->ir_builder_.SetInsertPoint(mod_res);
+    auto phi = cgen_state_->ir_builder_.CreatePHI(ret->getType(), 2);
+    phi->addIncoming(ret, mod_ok);
+    phi->addIncoming(llvm::ConstantInt::get(ret->getType(), inline_int_null_value(type)),
+                     mod_zero);
+    ret = phi;
+  } else {
+    cgen_state_->ir_builder_.SetInsertPoint(mod_zero);
+    cgen_state_->ir_builder_.CreateRet(cgen_state_->llInt(Executor::ERR_DIV_BY_ZERO));
+    cgen_state_->ir_builder_.SetInsertPoint(mod_ok);
+  }
   return ret;
 }
 

omniscidb/Shared/Config.h

@@ -78,6 +78,7 @@ struct InterruptConfig {
 struct CodegenConfig {
   bool inf_div_by_zero = false;
   bool null_div_by_zero = false;
+  bool null_mod_by_zero = false;
   bool hoist_literals = true;
   bool enable_filter_function = true;
 };

omniscidb/Tests/ArrowBasedExecuteTest.cpp

@@ -7278,6 +7278,23 @@ TEST_F(Select, ReturnNullFromDivByZero) {
   }
 }
 
+TEST_F(Select, ReturnNullFromModByZero) {
+  auto old_null_mod_by_zero = config().exec.codegen.null_mod_by_zero;
+  config().exec.codegen.null_mod_by_zero = true;
+  ScopeGuard sg = [old_null_mod_by_zero] {
+    config().exec.codegen.null_mod_by_zero = old_null_mod_by_zero;
+  };
+  for (auto dt : {ExecutorDeviceType::CPU, ExecutorDeviceType::GPU}) {
+    SKIP_NO_GPU();
+    c("SELECT x % 0 FROM test;", dt);
+    c("SELECT w % 0 FROM test;", dt);
+    c("SELECT y % 0 FROM test;", dt);
+    c("SELECT z % 0 FROM test;", dt);
+    c("SELECT t % 0 FROM test;", dt);
+    c("SELECT 1 % 0 FROM test;", dt);
+  }
+}
+
 TEST_F(Select, ReturnInfFromDivByZero) {
   config().exec.codegen.inf_div_by_zero = true;
   for (auto dt : {ExecutorDeviceType::CPU, ExecutorDeviceType::GPU}) {