mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-22 12:33:33 +02:00
df0b222a6e
This is required to use this function from isSafeToSpeculativelyExecute Reviewed By: hfinkel Differential Revision: http://reviews.llvm.org/D16231 llvm-svn: 267692
90 lines
4.1 KiB
C++
90 lines
4.1 KiB
C++
//===- Loads.h - Local load analysis --------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file declares simple local analyses for load instructions.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_ANALYSIS_LOADS_H
|
|
#define LLVM_ANALYSIS_LOADS_H
|
|
|
|
#include "llvm/Analysis/AliasAnalysis.h"
|
|
#include "llvm/IR/BasicBlock.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
|
|
namespace llvm {
|
|
|
|
class DataLayout;
|
|
class MDNode;
|
|
|
|
/// isDereferenceablePointer - Return true if this is always a dereferenceable
|
|
/// pointer. If the context instruction is specified perform context-sensitive
|
|
/// analysis and return true if the pointer is dereferenceable at the
|
|
/// specified instruction.
|
|
bool isDereferenceablePointer(const Value *V, const DataLayout &DL,
|
|
const Instruction *CtxI = nullptr,
|
|
const DominatorTree *DT = nullptr,
|
|
const TargetLibraryInfo *TLI = nullptr);
|
|
|
|
/// Returns true if V is always a dereferenceable pointer with alignment
|
|
/// greater or equal than requested. If the context instruction is specified
|
|
/// performs context-sensitive analysis and returns true if the pointer is
|
|
/// dereferenceable at the specified instruction.
|
|
bool isDereferenceableAndAlignedPointer(const Value *V, unsigned Align,
|
|
const DataLayout &DL,
|
|
const Instruction *CtxI = nullptr,
|
|
const DominatorTree *DT = nullptr,
|
|
const TargetLibraryInfo *TLI = nullptr);
|
|
|
|
/// isSafeToLoadUnconditionally - Return true if we know that executing a load
|
|
/// from this value cannot trap.
|
|
///
|
|
/// If DT and ScanFrom are specified this method performs context-sensitive
|
|
/// analysis and returns true if it is safe to load immediately before ScanFrom.
|
|
///
|
|
/// If it is not obviously safe to load from the specified pointer, we do a
|
|
/// quick local scan of the basic block containing ScanFrom, to determine if
|
|
/// the address is already accessed.
|
|
bool isSafeToLoadUnconditionally(Value *V, unsigned Align,
|
|
const DataLayout &DL,
|
|
Instruction *ScanFrom = nullptr,
|
|
const DominatorTree *DT = nullptr,
|
|
const TargetLibraryInfo *TLI = nullptr);
|
|
|
|
/// DefMaxInstsToScan - the default number of maximum instructions
|
|
/// to scan in the block, used by FindAvailableLoadedValue().
|
|
extern cl::opt<unsigned> DefMaxInstsToScan;
|
|
|
|
/// FindAvailableLoadedValue - Scan the ScanBB block backwards (starting at
|
|
/// the instruction before ScanFrom) checking to see if we have the value at
|
|
/// the memory address *Ptr locally available within a small number of
|
|
/// instructions. If the value is available, return it.
|
|
///
|
|
/// If not, return the iterator for the last validated instruction that the
|
|
/// value would be live through. If we scanned the entire block and didn't
|
|
/// find something that invalidates *Ptr or provides it, ScanFrom would be
|
|
/// left at begin() and this returns null. ScanFrom could also be left
|
|
///
|
|
/// MaxInstsToScan specifies the maximum instructions to scan in the block.
|
|
/// If it is set to 0, it will scan the whole block. You can also optionally
|
|
/// specify an alias analysis implementation, which makes this more precise.
|
|
///
|
|
/// If AATags is non-null and a load or store is found, the AA tags from the
|
|
/// load or store are recorded there. If there are no AA tags or if no access
|
|
/// is found, it is left unmodified.
|
|
Value *FindAvailableLoadedValue(LoadInst *Load, BasicBlock *ScanBB,
|
|
BasicBlock::iterator &ScanFrom,
|
|
unsigned MaxInstsToScan = DefMaxInstsToScan,
|
|
AliasAnalysis *AA = nullptr,
|
|
AAMDNodes *AATags = nullptr);
|
|
|
|
}
|
|
|
|
#endif
|