llvm-6502/include/llvm/CodeGen/Passes.h
Bob Wilson fe61fb1e10 Add a new pass on machine instructions to optimize away PHI cycles that
reduce down to a single value.  InstCombine already does this transformation
but DAG legalization may introduce new opportunities.  This has turned out to
be important for ARM where 64-bit values are split up during type legalization:
InstCombine is not able to remove the PHI cycles on the 64-bit values but
the separate 32-bit values can be optimized.  I measured the compile time 
impact of this (running llc on 176.gcc) and it was not significant.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95951 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-12 01:30:21 +00:00

205 lines
8.1 KiB
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//===-- Passes.h - Target independent code generation passes ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines interfaces to access the target independent code generation
// passes provided by the LLVM backend.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_PASSES_H
#define LLVM_CODEGEN_PASSES_H
#include "llvm/Target/TargetMachine.h"
#include <string>
namespace llvm {
class FunctionPass;
class PassInfo;
class TargetLowering;
class RegisterCoalescer;
class raw_ostream;
/// createUnreachableBlockEliminationPass - The LLVM code generator does not
/// work well with unreachable basic blocks (what live ranges make sense for a
/// block that cannot be reached?). As such, a code generator should either
/// not instruction select unreachable blocks, or it can run this pass as it's
/// last LLVM modifying pass to clean up blocks that are not reachable from
/// the entry block.
FunctionPass *createUnreachableBlockEliminationPass();
/// MachineFunctionPrinter pass - This pass prints out the machine function to
/// the given stream, as a debugging tool.
FunctionPass *createMachineFunctionPrinterPass(raw_ostream &OS,
const std::string &Banner ="");
/// MachineLoopInfo pass - This pass is a loop analysis pass.
///
extern const PassInfo *const MachineLoopInfoID;
/// MachineDominators pass - This pass is a machine dominators analysis pass.
///
extern const PassInfo *const MachineDominatorsID;
/// PHIElimination pass - This pass eliminates machine instruction PHI nodes
/// by inserting copy instructions. This destroys SSA information, but is the
/// desired input for some register allocators. This pass is "required" by
/// these register allocator like this: AU.addRequiredID(PHIEliminationID);
///
extern const PassInfo *const PHIEliminationID;
/// StrongPHIElimination pass - This pass eliminates machine instruction PHI
/// nodes by inserting copy instructions. This destroys SSA information, but
/// is the desired input for some register allocators. This pass is
/// "required" by these register allocator like this:
/// AU.addRequiredID(PHIEliminationID);
/// This pass is still in development
extern const PassInfo *const StrongPHIEliminationID;
extern const PassInfo *const PreAllocSplittingID;
/// SimpleRegisterCoalescing pass. Aggressively coalesces every register
/// copy it can.
///
extern const PassInfo *const SimpleRegisterCoalescingID;
/// TwoAddressInstruction pass - This pass reduces two-address instructions to
/// use two operands. This destroys SSA information but it is desired by
/// register allocators.
extern const PassInfo *const TwoAddressInstructionPassID;
/// UnreachableMachineBlockElimination pass - This pass removes unreachable
/// machine basic blocks.
extern const PassInfo *const UnreachableMachineBlockElimID;
/// DeadMachineInstructionElim pass - This pass removes dead machine
/// instructions.
///
FunctionPass *createDeadMachineInstructionElimPass();
/// Creates a register allocator as the user specified on the command line.
///
FunctionPass *createRegisterAllocator();
/// LocalRegisterAllocation Pass - This pass register allocates the input code
/// a basic block at a time, yielding code better than the simple register
/// allocator, but not as good as a global allocator.
///
FunctionPass *createLocalRegisterAllocator();
/// LinearScanRegisterAllocation Pass - This pass implements the linear scan
/// register allocation algorithm, a global register allocator.
///
FunctionPass *createLinearScanRegisterAllocator();
/// PBQPRegisterAllocation Pass - This pass implements the Partitioned Boolean
/// Quadratic Prograaming (PBQP) based register allocator.
///
FunctionPass *createPBQPRegisterAllocator();
/// SimpleRegisterCoalescing Pass - Coalesce all copies possible. Can run
/// independently of the register allocator.
///
RegisterCoalescer *createSimpleRegisterCoalescer();
/// PrologEpilogCodeInserter Pass - This pass inserts prolog and epilog code,
/// and eliminates abstract frame references.
///
FunctionPass *createPrologEpilogCodeInserter();
/// LowerSubregs Pass - This pass lowers subregs to register-register copies
/// which yields suboptimal, but correct code if the register allocator
/// cannot coalesce all subreg operations during allocation.
///
FunctionPass *createLowerSubregsPass();
/// createPostRAScheduler - This pass performs post register allocation
/// scheduling.
FunctionPass *createPostRAScheduler(CodeGenOpt::Level OptLevel);
/// BranchFolding Pass - This pass performs machine code CFG based
/// optimizations to delete branches to branches, eliminate branches to
/// successor blocks (creating fall throughs), and eliminating branches over
/// branches.
FunctionPass *createBranchFoldingPass(bool DefaultEnableTailMerge);
/// TailDuplicate Pass - Duplicate blocks with unconditional branches
/// into tails of their predecessors.
FunctionPass *createTailDuplicatePass(bool PreRegAlloc = false);
/// IfConverter Pass - This pass performs machine code if conversion.
FunctionPass *createIfConverterPass();
/// Code Placement Pass - This pass optimize code placement and aligns loop
/// headers to target specific alignment boundary.
FunctionPass *createCodePlacementOptPass();
/// getRegisterAllocator - This creates an instance of the register allocator
/// for the Sparc.
FunctionPass *getRegisterAllocator(TargetMachine &T);
/// IntrinsicLowering Pass - Performs target-independent LLVM IR
/// transformations for highly portable strategies.
FunctionPass *createGCLoweringPass();
/// MachineCodeAnalysis Pass - Target-independent pass to mark safe points in
/// machine code. Must be added very late during code generation, just prior
/// to output, and importantly after all CFG transformations (such as branch
/// folding).
FunctionPass *createGCMachineCodeAnalysisPass();
/// Deleter Pass - Releases GC metadata.
///
FunctionPass *createGCInfoDeleter();
/// Creates a pass to print GC metadata.
///
FunctionPass *createGCInfoPrinter(raw_ostream &OS);
/// createMachineLICMPass - This pass performs LICM on machine instructions.
///
FunctionPass *createMachineLICMPass();
/// createMachineSinkingPass - This pass performs sinking on machine
/// instructions.
FunctionPass *createMachineSinkingPass();
/// createOptimizeExtsPass - This pass performs sign / zero extension
/// optimization by increasing uses of extended values.
FunctionPass *createOptimizeExtsPass();
/// createOptimizePHIsPass - This pass optimizes machine instruction PHIs
/// to take advantage of opportunities created during DAG legalization.
FunctionPass *createOptimizePHIsPass();
/// createStackSlotColoringPass - This pass performs stack slot coloring.
FunctionPass *createStackSlotColoringPass(bool);
/// createStackProtectorPass - This pass adds stack protectors to functions.
FunctionPass *createStackProtectorPass(const TargetLowering *tli);
/// createMachineVerifierPass - This pass verifies cenerated machine code
/// instructions for correctness.
///
/// @param allowPhysDoubleDefs ignore double definitions of
/// registers. Useful before LiveVariables has run.
FunctionPass *createMachineVerifierPass(bool allowDoubleDefs);
/// createDwarfEHPass - This pass mulches exception handling code into a form
/// adapted to code generation. Required if using dwarf exception handling.
FunctionPass *createDwarfEHPass(const TargetLowering *tli, bool fast);
/// createSjLjEHPass - This pass adapts exception handling code to use
/// the GCC-style builtin setjmp/longjmp (sjlj) to handling EH control flow.
FunctionPass *createSjLjEHPass(const TargetLowering *tli);
} // End llvm namespace
#endif