Lowers COPY nodes of EFLAGS by directly extracting and preserving individual flag bits. More...
#include "X86.h"#include "X86InstrBuilder.h"#include "X86InstrInfo.h"#include "X86Subtarget.h"#include "llvm/ADT/ArrayRef.h"#include "llvm/ADT/DenseMap.h"#include "llvm/ADT/PostOrderIterator.h"#include "llvm/ADT/STLExtras.h"#include "llvm/ADT/ScopeExit.h"#include "llvm/ADT/SmallPtrSet.h"#include "llvm/ADT/SmallSet.h"#include "llvm/ADT/SmallVector.h"#include "llvm/ADT/SparseBitVector.h"#include "llvm/ADT/Statistic.h"#include "llvm/CodeGen/MachineBasicBlock.h"#include "llvm/CodeGen/MachineConstantPool.h"#include "llvm/CodeGen/MachineDominators.h"#include "llvm/CodeGen/MachineFunction.h"#include "llvm/CodeGen/MachineFunctionPass.h"#include "llvm/CodeGen/MachineInstr.h"#include "llvm/CodeGen/MachineInstrBuilder.h"#include "llvm/CodeGen/MachineModuleInfo.h"#include "llvm/CodeGen/MachineOperand.h"#include "llvm/CodeGen/MachineRegisterInfo.h"#include "llvm/CodeGen/MachineSSAUpdater.h"#include "llvm/CodeGen/TargetInstrInfo.h"#include "llvm/CodeGen/TargetRegisterInfo.h"#include "llvm/CodeGen/TargetSchedule.h"#include "llvm/CodeGen/TargetSubtargetInfo.h"#include "llvm/IR/DebugLoc.h"#include "llvm/MC/MCSchedule.h"#include "llvm/Pass.h"#include "llvm/Support/CommandLine.h"#include "llvm/Support/Debug.h"#include "llvm/Support/raw_ostream.h"#include <algorithm>#include <cassert>#include <iterator>#include <utility>
Go to the source code of this file.
Macros | |
| #define | PASS_KEY "x86-flags-copy-lowering" |
| #define | DEBUG_TYPE PASS_KEY |
| #define | LLVM_EXPAND_INSTR_SIZES(MNEMONIC, SUFFIX) |
| #define | LLVM_EXPAND_ADC_SBB_INSTR(MNEMONIC) |
Functions | |
| STATISTIC (NumCopiesEliminated, "Number of copies of EFLAGS eliminated") | |
| STATISTIC (NumSetCCsInserted, "Number of setCC instructions inserted") | |
| STATISTIC (NumTestsInserted, "Number of test instructions inserted") | |
| STATISTIC (NumAddsInserted, "Number of adds instructions inserted") | |
| INITIALIZE_PASS_BEGIN (X86FlagsCopyLoweringPass, DEBUG_TYPE, "X86 EFLAGS copy lowering", false, false) INITIALIZE_PASS_END(X86FlagsCopyLoweringPass | |
| static FlagArithMnemonic | getMnemonicFromOpcode (unsigned Opcode) |
| static MachineBasicBlock & | splitBlock (MachineBasicBlock &MBB, MachineInstr &SplitI, const X86InstrInfo &TII) |
| static X86::CondCode | getCondFromFCMOV (unsigned Opcode) |
Variables | |
| DEBUG_TYPE | |
| X86 EFLAGS copy | lowering |
| X86 EFLAGS copy | false |
Detailed Description
Lowers COPY nodes of EFLAGS by directly extracting and preserving individual flag bits.
We have to do this by carefully analyzing and rewriting the usage of the copied EFLAGS register because there is no general way to rematerialize the entire EFLAGS register safely and efficiently. Using popf both forces dynamic stack adjustment and can create correctness issues due to IF, TF, and other non-status flags being overwritten. Using sequences involving SAHF don't work on all x86 processors and are often quite slow compared to directly testing a single status preserved in its own GPR.
Definition in file X86FlagsCopyLowering.cpp.
Macro Definition Documentation
◆ DEBUG_TYPE
| #define DEBUG_TYPE PASS_KEY |
Definition at line 66 of file X86FlagsCopyLowering.cpp.
◆ LLVM_EXPAND_ADC_SBB_INSTR
| #define LLVM_EXPAND_ADC_SBB_INSTR | ( | MNEMONIC | ) |
◆ LLVM_EXPAND_INSTR_SIZES
| #define LLVM_EXPAND_INSTR_SIZES | ( | MNEMONIC, | |
| SUFFIX | |||
| ) |
◆ PASS_KEY
| #define PASS_KEY "x86-flags-copy-lowering" |
Definition at line 65 of file X86FlagsCopyLowering.cpp.
Function Documentation
◆ getCondFromFCMOV()
|
static |
Definition at line 342 of file X86FlagsCopyLowering.cpp.
References llvm::X86::COND_A, llvm::X86::COND_AE, llvm::X86::COND_B, llvm::X86::COND_BE, llvm::X86::COND_E, llvm::X86::COND_INVALID, llvm::X86::COND_NE, llvm::X86::COND_NP, and llvm::X86::COND_P.
◆ getMnemonicFromOpcode()
|
static |
Definition at line 168 of file X86FlagsCopyLowering.cpp.
References LLVM_EXPAND_ADC_SBB_INSTR, LLVM_EXPAND_INSTR_SIZES, r1(), and llvm::report_fatal_error().
◆ INITIALIZE_PASS_BEGIN()
| INITIALIZE_PASS_BEGIN | ( | X86FlagsCopyLoweringPass | , |
| DEBUG_TYPE | , | ||
| "X86 EFLAGS copy lowering" | , | ||
| false | , | ||
| false | |||
| ) |
◆ splitBlock()
|
static |
Definition at line 242 of file X86FlagsCopyLowering.cpp.
References assert(), llvm::X86::COND_INVALID, llvm::X86::getCondFromBranch(), llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::MachineOperand::getMBB(), llvm::MachineInstr::getOperand(), llvm::MachineBasicBlock::getParent(), llvm::MachineInstr::getParent(), llvm::MachineBasicBlock::instr_end(), llvm::MachineInstr::isBranch(), MBB, and MI.
◆ STATISTIC() [1/4]
| STATISTIC | ( | NumAddsInserted | , |
| "Number of adds instructions inserted" | |||
| ) |
◆ STATISTIC() [2/4]
| STATISTIC | ( | NumCopiesEliminated | , |
| "Number of copies of EFLAGS eliminated" | |||
| ) |
◆ STATISTIC() [3/4]
| STATISTIC | ( | NumSetCCsInserted | , |
| "Number of setCC instructions inserted" | |||
| ) |
◆ STATISTIC() [4/4]
| STATISTIC | ( | NumTestsInserted | , |
| "Number of test instructions inserted" | |||
| ) |
Variable Documentation
◆ DEBUG_TYPE
| DEBUG_TYPE |
Definition at line 137 of file X86FlagsCopyLowering.cpp.
◆ false
| X86 EFLAGS copy false |
Definition at line 138 of file X86FlagsCopyLowering.cpp.
◆ lowering
| X86 EFLAGS copy lowering |
Definition at line 138 of file X86FlagsCopyLowering.cpp.
