[llvm] [RISCV] add computeKnownBitsForTargetNode for RISCVISD::SRLW (PR #155995)

[Shreeyash Pandey via llvm-commits]

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@@ -0,0 +1,109 @@
+//===----------------------------------------------------------------------===//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVISelLowering.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Module.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/KnownBits.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+
+class RISCVSelectionDAGTest : public testing::Test {
+
+protected:
+  static void SetUpTestCase() {
+    LLVMInitializeRISCVTargetInfo();
+    LLVMInitializeRISCVTarget();
+    LLVMInitializeRISCVTargetMC();
+  }
+
+  void SetUp() override {
+    StringRef Assembly = "define void @f() { ret void }";
+
+    Triple TargetTriple("riscv64", "unknown", "linux");
+
+    std::string Error;
+    const Target *T = TargetRegistry::lookupTarget("", TargetTriple, Error);
+
+    TargetOptions Options;
+    TM = std::unique_ptr<TargetMachine>(T->createTargetMachine(
+        TargetTriple, "generic", "", Options, std::nullopt, std::nullopt,
+        CodeGenOptLevel::Default));
+
+    SMDiagnostic SMError;
+    M = parseAssemblyString(Assembly, SMError, Context);
+    if (!M)
+      report_fatal_error(SMError.getMessage());
+    M->setDataLayout(TM->createDataLayout());
+
+    F = M->getFunction("f");
+    if (!F)
+      report_fatal_error("Function 'f' not found");
+
+    MachineModuleInfo MMI(TM.get());
+
+    MF = std::make_unique<MachineFunction>(*F, *TM, *TM->getSubtargetImpl(*F),
+                                           MMI.getContext(), /*FunctionNum*/ 0);
+
+    DAG = std::make_unique<SelectionDAG>(*TM, CodeGenOptLevel::None);
+    if (!DAG)
+      report_fatal_error("SelectionDAG allocation failed");
+
+    OptimizationRemarkEmitter ORE(F);
+    DAG->init(*MF, ORE, /*LibInfo*/ nullptr, /*AA*/ nullptr,
+              /*AC*/ nullptr, /*MDT*/ nullptr, /*MSDT*/ nullptr, MMI, nullptr);
+  }
+
+  LLVMContext Context;
+  std::unique_ptr<TargetMachine> TM;
+  std::unique_ptr<Module> M;
+  Function *F = nullptr;
+  std::unique_ptr<MachineFunction> MF;
+  std::unique_ptr<SelectionDAG> DAG;
+};
+
+/// SRLW: Logical Shift Right
+TEST_F(RISCVSelectionDAGTest, computeKnownBits_SRLW) {
+  // Following DAG is created from this IR snippet:
+  //
+  // define i64 @f(i32 %x, i32 %y) {
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bojle wrote:

So, would you recommend I work on a lit test too? What about the current unittest (drop it/keep it)?

https://github.com/llvm/llvm-project/pull/155995