[llvm] [X86] computeKnownBitsForTargetNode - add X86ISD::FANDN coverage and X86SelectionDAGTest infrastructure (PR #181994)

[Phoebe Wang via llvm-commits]

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@@ -0,0 +1,103 @@
+//===----------------------------------------------------------------------===//
+// 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 "X86ISelLowering.h"
+#include "llvm/Analysis/MemoryLocation.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/Target/TargetMachine.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+
+class X86SelectionDAGTest : public testing::Test {
+protected:
+  const TargetSubtargetInfo *STI;
+
+  static void SetUpTestCase() {
+    LLVMInitializeX86TargetInfo();
+    LLVMInitializeX86Target();
+    LLVMInitializeX86TargetMC();
+  }
+
+  void SetUp() override {
+    StringRef Assembly = "define void @f() { ret void }";
+
+    Triple TargetTriple("x86_64--");
+    std::string Error;
+    const Target *T = TargetRegistry::lookupTarget("", TargetTriple, Error);
+
+    TargetOptions Options;
+    TM = std::unique_ptr<TargetMachine>(T->createTargetMachine(
+        TargetTriple, "x86-64-v4", "", Options, std::nullopt, std::nullopt,
+        CodeGenOptLevel::Aggressive));
+
+    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("F?");
+
+    MachineModuleInfo MMI(TM.get());
+
+    STI = TM->getSubtargetImpl(*F);
+    MF = std::make_unique<MachineFunction>(*F, *TM, *STI, MMI.getContext(), 0);
+
+    DAG = std::make_unique<SelectionDAG>(*TM, CodeGenOptLevel::None);
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phoebewang wrote:

Why testing SelectionDAG with Opt level none?

https://github.com/llvm/llvm-project/pull/181994