[llvm] [RISCV] Introduce the RISCVLoopIdiomRecognizePass (PR #92441)

[Min-Yih Hsu via llvm-commits]

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@@ -0,0 +1,752 @@
+//===-------- RISCVLoopIdiomRecognize.cpp - Loop idiom recognition --------===//
+//
+// 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 "RISCVLoopIdiomRecognize.h"
+#include "llvm/ADT/ScopeExit.h"
+#include "llvm/Analysis/DomTreeUpdater.h"
+#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicsRISCV.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/TargetParser/RISCVTargetParser.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "riscv-loop-idiom"
+
+static cl::opt<bool>
+    DisableAll("riscv-disable-all-loop-idiom", cl::Hidden, cl::init(true),
+               cl::desc("Disable RISCV Loop Idiom Recognize Pass."));
+
+static cl::opt<bool> DisableByteCmp(
+    "disable-riscv-loop-idiom-bytecmp", cl::Hidden, cl::init(false),
+    cl::desc("Proceed with RISCV Loop Idiom Recognize Pass, but do "
+             "not convert byte-compare loop(s)."));
+
+// CustomLoopIdiomLMUL can be used to customize LMUL for vectorizing loops.
+// It uses the exponent value to represent LMUL i.e. 0 -> LMUL 1, 1 -> LMUL 2, 2
+// -> LMUL 4, 3 -> LMUL 8, etc.
+static cl::opt<unsigned>
+    CustomLoopIdiomLMUL("riscv-loop-idiom-lmul", cl::Hidden, cl::init(1),
+                        cl::Optional,
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mshockwave wrote:

That's right. The cl::Optional is removed now.

https://github.com/llvm/llvm-project/pull/92441