[llvm] [SLP][Modularization][NFC] Extract type and constant helpers into SLPUtils (1/3) (PR #206881)

[Madhur Amilkanthwar via llvm-commits]

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+//===- SLPUtils.h - SLP Vectorizer free utility helpers --------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Internal header used by SLPVectorizer.cpp. It declares free helper
+// functions that do not depend on BoUpSLP, InstructionsState, or any other
+// SLP-private type. Splitting them out keeps SLPVectorizer.cpp focused on
+// the build / legality / cost / codegen pipeline.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TRANSFORMS_VECTORIZE_SLPVECTORIZER_SLPUTILS_H
+#define LLVM_LIB_TRANSFORMS_VECTORIZE_SLPVECTORIZER_SLPUTILS_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Value.h"
+
+#include <optional>
+#include <type_traits>
+
+namespace llvm {
+class Instruction;
+class Type;
+class Value;
+} // namespace llvm
+
+namespace llvm::slpvectorizer {
+
+/// \returns True if the value is a constant (but not globals/constant
+/// expressions).
+bool isConstant(Value *V);
+
+/// Checks if \p V is one of vector-like instructions, i.e. undef,
+/// insertelement/extractelement with constant indices for fixed vector type
+/// or extractvalue instruction.
+bool isVectorLikeInstWithConstOps(Value *V);
+
+/// \returns the number of elements for Ty.
+unsigned getNumElements(Type *Ty);
+
+/// Returns power-of-2 number of elements in a single register (part), given
+/// the total number of elements \p Size and number of registers (parts) \p
+/// NumParts.
+unsigned getPartNumElems(unsigned Size, unsigned NumParts);
+
+/// Returns correct remaining number of elements, considering total amount
+/// \p Size, (power-of-2 number) of elements in a single register
+/// \p PartNumElems and current register (part) \p Part.
+unsigned getNumElems(unsigned Size, unsigned PartNumElems, unsigned Part);
+
+/// \returns true if all of the instructions in \p VL are in the same block
+/// or false otherwise.
+bool allSameBlock(ArrayRef<Value *> VL);
+
+/// \returns True if all of the values in \p VL are constants (but not
+/// globals/constant expressions).
+bool allConstant(ArrayRef<Value *> VL);
+
+/// \returns True if all of the values in \p VL are identical or some of them
+/// are UndefValue.
+bool isSplat(ArrayRef<Value *> VL);
+
+/// \returns true if all of the values in \p VL use the same opcode.
+/// For comparison instructions, also checks if predicates match.
+/// PoisonValues are considered matching. Interchangeable instructions are
+/// not considered.
+bool allSameOpcode(ArrayRef<Value *> VL);
+
+/// \returns True if Extract{Value,Element} instruction extracts element Idx.
+std::optional<unsigned> getExtractIndex(const Instruction *E);
+
+/// \returns true iff every value in \p VL has the same Type as the first.
+bool allSameType(ArrayRef<Value *> VL);
+
+/// \returns inserting or extracting index of InsertElement / ExtractElement
+/// instruction, using \p Offset as base offset for index.
+template <typename T>
+std::optional<unsigned> getInsertExtractIndex(const Value *Inst,
+                                              unsigned Offset) {
+  static_assert(std::is_same_v<T, InsertElementInst> ||
+                    std::is_same_v<T, ExtractElementInst>,
+                "unsupported T");
+  int Index = Offset;
+  if (const auto *IE = dyn_cast<T>(Inst)) {
+    const auto *VT = dyn_cast<FixedVectorType>(IE->getType());
+    if (!VT)
+      return std::nullopt;
+    const auto *CI = dyn_cast<ConstantInt>(IE->getOperand(2));
+    if (!CI)
+      return std::nullopt;
+    if (CI->getValue().uge(VT->getNumElements()))
+      return std::nullopt;
+    Index *= VT->getNumElements();
+    Index += CI->getZExtValue();
+    return Index;
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madhur13490 wrote:

Sorry, this is NFC patch and I want to do verbatim move. I'd like to avoid such changes in this patch.

https://github.com/llvm/llvm-project/pull/206881