mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-10-19 02:25:35 +00:00
3d03d60ca8
This adds a set of utility functions for collecting 'ephemeral' values. These are LLVM IR values that are used only by @llvm.assume intrinsics (directly or indirectly), and thus will be removed prior to code generation, implying that they should be considered free for certain purposes (like inlining). The inliner's cost analysis, and a few other passes, have been updated to account for ephemeral values using the provided functionality. This functionality is important for the usability of @llvm.assume, because it limits the "non-local" side-effects of adding llvm.assume on inlining, loop unrolling, etc. (these are hints, and do not generate code, so they should not directly contribute to estimates of execution cost). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217335 91177308-0d34-0410-b5e6-96231b3b80d8
108 lines
3.7 KiB
C++
108 lines
3.7 KiB
C++
//===- CodeMetrics.h - Code cost measurements -------------------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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 AssumptionTracker;
|
|
class BasicBlock;
|
|
class Loop;
|
|
class Function;
|
|
class Instruction;
|
|
class DataLayout;
|
|
class TargetTransformInfo;
|
|
class Value;
|
|
|
|
/// \brief 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);
|
|
|
|
/// \brief Utility to calculate the size and a few similar metrics for a set
|
|
/// of basic blocks.
|
|
struct CodeMetrics {
|
|
/// \brief True if this function contains a call to setjmp or other functions
|
|
/// with attribute "returns twice" without having the attribute itself.
|
|
bool exposesReturnsTwice;
|
|
|
|
/// \brief True if this function calls itself.
|
|
bool isRecursive;
|
|
|
|
/// \brief 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;
|
|
|
|
/// \brief True if this function calls alloca (in the C sense).
|
|
bool usesDynamicAlloca;
|
|
|
|
/// \brief Number of instructions in the analyzed blocks.
|
|
unsigned NumInsts;
|
|
|
|
/// \brief Number of analyzed blocks.
|
|
unsigned NumBlocks;
|
|
|
|
/// \brief Keeps track of basic block code size estimates.
|
|
DenseMap<const BasicBlock *, unsigned> NumBBInsts;
|
|
|
|
/// \brief Keep track of the number of calls to 'big' functions.
|
|
unsigned NumCalls;
|
|
|
|
/// \brief 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;
|
|
|
|
/// \brief How many instructions produce vector values.
|
|
///
|
|
/// The inliner is more aggressive with inlining vector kernels.
|
|
unsigned NumVectorInsts;
|
|
|
|
/// \brief How many 'ret' instructions the blocks contain.
|
|
unsigned NumRets;
|
|
|
|
CodeMetrics()
|
|
: exposesReturnsTwice(false), isRecursive(false), notDuplicatable(false),
|
|
usesDynamicAlloca(false), NumInsts(0), NumBlocks(0), NumCalls(0),
|
|
NumInlineCandidates(0), NumVectorInsts(0), NumRets(0) {}
|
|
|
|
/// \brief Add information about a block to the current state.
|
|
void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI,
|
|
SmallPtrSetImpl<const Value*> &EphValues);
|
|
|
|
/// \brief Collect a loop's ephemeral values (those used only by an assume
|
|
/// or similar intrinsics in the loop).
|
|
static void collectEphemeralValues(const Loop *L, AssumptionTracker *AT,
|
|
SmallPtrSetImpl<const Value*> &EphValues);
|
|
|
|
/// \brief Collect a functions's ephemeral values (those used only by an
|
|
/// assume or similar intrinsics in the function).
|
|
static void collectEphemeralValues(const Function *L, AssumptionTracker *AT,
|
|
SmallPtrSetImpl<const Value*> &EphValues);
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|