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//===- CodeMetrics.h - Code cost measurements -------------------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file implements various weight measurements for code, helping
// the Inliner and other passes decide whether to duplicate its contents.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_CODEMETRICS_H
#define LLVM_ANALYSIS_CODEMETRICS_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/IR/CallSite.h"
namespace llvm {
class AssumptionCache;
class BasicBlock;
class Loop;
class Function;
class Instruction;
class DataLayout;
class TargetTransformInfo;
class Value;
/// Check whether a call will lower to something small.
///
/// This tests checks whether this callsite will lower to something
/// significantly cheaper than a traditional call, often a single
/// instruction. Note that if isInstructionFree(CS.getInstruction()) would
/// return true, so will this function.
bool callIsSmall(ImmutableCallSite CS);
/// Utility to calculate the size and a few similar metrics for a set
/// of basic blocks.
struct CodeMetrics {
/// True if this function contains a call to setjmp or other functions
/// with attribute "returns twice" without having the attribute itself.
bool exposesReturnsTwice = false;
/// True if this function calls itself.
bool isRecursive = false;
/// True if this function cannot be duplicated.
///
/// True if this function contains one or more indirect branches, or it contains
/// one or more 'noduplicate' instructions.
bool notDuplicatable = false;
/// True if this function contains a call to a convergent function.
bool convergent = false;
/// True if this function calls alloca (in the C sense).
bool usesDynamicAlloca = false;
/// Number of instructions in the analyzed blocks.
unsigned NumInsts = false;
/// Number of analyzed blocks.
unsigned NumBlocks = false;
/// Keeps track of basic block code size estimates.
DenseMap<const BasicBlock *, unsigned> NumBBInsts;
/// Keep track of the number of calls to 'big' functions.
unsigned NumCalls = false;
/// The number of calls to internal functions with a single caller.
///
/// These are likely targets for future inlining, likely exposed by
/// interleaved devirtualization.
unsigned NumInlineCandidates = 0;
/// How many instructions produce vector values.
///
/// The inliner is more aggressive with inlining vector kernels.
unsigned NumVectorInsts = 0;
/// How many 'ret' instructions the blocks contain.
unsigned NumRets = 0;
/// Add information about a block to the current state.
void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI,
const SmallPtrSetImpl<const Value*> &EphValues);
/// Collect a loop's ephemeral values (those used only by an assume
/// or similar intrinsics in the loop).
static void collectEphemeralValues(const Loop *L, AssumptionCache *AC,
SmallPtrSetImpl<const Value *> &EphValues);
/// Collect a functions's ephemeral values (those used only by an
/// assume or similar intrinsics in the function).
static void collectEphemeralValues(const Function *L, AssumptionCache *AC,
SmallPtrSetImpl<const Value *> &EphValues);
};
}
#endif
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