[llvm] X86: make VBMI2 funnel shifts use VSHLD/VSHRD for const splats (PR #169401)

[Simon Pilgrim via llvm-commits]

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@@ -0,0 +1,163 @@
+//===- FunnelShiftCombineTest.cpp - X86 Funnel Shift Combine Tests --------===//
+//
+// 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 "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/Module.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+class X86FunnelShiftCombineTest : public testing::Test {
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RKSimon wrote:

Still not sure this is necessary - we already have pretty thorough test coverage inside llvm\test\CodeGen\X86 - @phoebewang WDYT?

https://github.com/llvm/llvm-project/pull/169401