1 files changed, 89 insertions, 0 deletions
diff --git a/backend/unittests/CodeGen/GlobalISel/RegBankSelectTest.cpp b/backend/unittests/CodeGen/GlobalISel/RegBankSelectTest.cpp
new file mode 100644
index 0000000..785844f
--- /dev/null
+++ b/backend/unittests/CodeGen/GlobalISel/RegBankSelectTest.cpp
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "rcc/CodeGen/GlobalISel/RegBankSelect.h"
+
+#include "GISel/RISCVRegisterBankInfo.h"
+#include "GISelMITest.h"
+#include "rcc/Target/RISCV/RISCVSubtarget.h"
+#include "rcc/Target/RISCV/RISCVTarget.h"
+
+#include <cstdint>
+
+namespace {
+
+using rcc::test::buildConstant;
+using rcc::test::createFixture;
+using rcc::test::createRegister;
+using rcc::test::TestContext;
+
+void testBankConflict(TestContext &Context) {
+  auto Target = rcc::riscv::createTargetDescription();
+  auto Fixture = createFixture(Context, "pipeline_bank_conflict", 4);
+  Context.expect(Target.has_value() && Fixture.Function != nullptr && Fixture.Entry != nullptr,
+                 "bank conflict fixture must be complete");
+  if (!Target || !Fixture.Function || Fixture.Entry == nullptr)
+    return;
+  const rcc::Register Value = createRegister(Context, *Fixture.Function, 64);
+  Context.expect(
+      Fixture.Function->registerInfo()
+          .setRegisterBank(Value, rcc::RegisterBankID::fromValue(
+                                      static_cast<std::uint32_t>(rcc::riscv::RegisterBank::FPR)))
+          .has_value(),
+      "conflicting bank assignment must be constructible");
+  Fixture.Function->properties() = {rcc::MachineFunctionProperty::Legalized};
+  const rcc::riscv::RISCVSubtarget Subtarget(rcc::riscv::RISCVSubtargetFeatures::rv64gc());
+  rcc::RegBankSelect Pass(Subtarget.getRegBankInfo());
+  rcc::MachineFunctionAnalysisManager Analyses;
+  auto Result = Pass.run(*Fixture.Function, *Target, Analyses);
+  Context.expect(!Result && Result.error().code() == rcc::ErrorCode::VerificationError,
+                 "bank selection must reject a conflicting pre-existing bank");
+  auto Info = Fixture.Function->registerInfo().virtualRegisterInfo(Value);
+  Context.expect(Info && Info->get().Bank, "failed bank selection must preserve a bank assignment");
+  if (!Info || !Info->get().Bank)
+    return;
+  const rcc::RegisterBankID Bank = Info->get().Bank.value_or(rcc::RegisterBankID{});
+  Context.expect(Bank == rcc::RegisterBankID::fromValue(
+                             static_cast<std::uint32_t>(rcc::riscv::RegisterBank::FPR)),
+                 "failed bank selection must preserve the original bank assignment");
+}
+
+void testBankSelectionDoesNotAssignAClass(TestContext &Context) {
+  auto Target = rcc::riscv::createTargetDescription();
+  auto Fixture = createFixture(Context, "pipeline_bank_class", 5);
+  Context.expect(Target.has_value() && Fixture.Function != nullptr && Fixture.Entry != nullptr,
+                 "bank class fixture must be complete");
+  if (!Target || !Fixture.Function || Fixture.Entry == nullptr)
+    return;
+  const rcc::Register Value = createRegister(Context, *Fixture.Function, 64);
+  rcc::MachineIRBuilder Builder(*Fixture.Function, *Target);
+  if (Value.isNoRegister() || !Builder.setInsertPoint(*Fixture.Entry) ||
+      !buildConstant(Context, Builder, Value, 7))
+    return;
+  const auto GPR =
+      rcc::RegisterBankID::fromValue(static_cast<std::uint32_t>(rcc::riscv::RegisterBank::GPR));
+  Context.expect(Fixture.Function->registerInfo().setRegisterBank(Value, GPR).has_value(),
+                 "pre-existing GPR bank must be assignable");
+  Fixture.Function->properties() = {rcc::MachineFunctionProperty::Legalized};
+  const rcc::riscv::RISCVSubtarget Subtarget(rcc::riscv::RISCVSubtargetFeatures::rv64gc());
+  rcc::RegBankSelect Pass(Subtarget.getRegBankInfo());
+  rcc::MachineFunctionAnalysisManager Analyses;
+  auto Result = Pass.run(*Fixture.Function, *Target, Analyses);
+  Context.expect(Result.has_value() && !Result->Changed,
+                 "bank selection must preserve an existing bank-only mapping");
+  auto Info = Fixture.Function->registerInfo().virtualRegisterInfo(Value);
+  Context.expect(Info && Info->get().Bank && !Info->get().RegClass,
+                 "bank selection must not assign a register class");
+  if (!Info || !Info->get().Bank)
+    return;
+  Context.expect(Info->get().Bank.value_or(rcc::RegisterBankID{}) == GPR,
+                 "bank selection must preserve the GPR bank");
+}
+
+} // namespace
+
+int main() {
+  TestContext Context;
+  testBankConflict(Context);
+  testBankSelectionDoesNotAssignAClass(Context);
+  return Context.result();
+}