llvm-6502/include/llvm/Support/StandardPasses.h
Chris Lattner 734d7c2a7e make a couple of changes to the standard pass pipeline:
1. Only run the early (in the module pass pipe) instcombine/simplifycfg
   if the "unit at a time" passes they are cleaning up after runs.

2. Move the "clean up after the unroller" pass to the very end of the
   function-level pass pipeline.  Loop unroll uses instsimplify now,
   so it doesn't create a ton of trash.  Moving instcombine later allows
   it to clean up after opportunities are exposed by GVN, DSE, etc.

3. Introduce some phase ordering tests for things that are specifically
   intended to be simplified by the full optimizer as a whole.

This resolves PR2338, and is progress towards PR6627, which will be 
generating code that looks similar to test2.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130241 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 20:45:33 +00:00

245 lines
11 KiB
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//===-- llvm/Support/StandardPasses.h - Standard pass lists -----*- 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 utility functions for creating a "standard" set of
// optimization passes, so that compilers and tools which use optimization
// passes use the same set of standard passes.
//
// These are implemented as inline functions so that we do not have to worry
// about link issues.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_STANDARDPASSES_H
#define LLVM_SUPPORT_STANDARDPASSES_H
#include "llvm/PassManager.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/IPO.h"
namespace llvm {
static inline void createStandardAliasAnalysisPasses(PassManagerBase *PM) {
// Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
// BasicAliasAnalysis wins if they disagree. This is intended to help
// support "obvious" type-punning idioms.
PM->add(createTypeBasedAliasAnalysisPass());
PM->add(createBasicAliasAnalysisPass());
}
/// createStandardFunctionPasses - Add the standard list of function passes to
/// the provided pass manager.
///
/// \arg OptimizationLevel - The optimization level, corresponding to -O0,
/// -O1, etc.
static inline void createStandardFunctionPasses(PassManagerBase *PM,
unsigned OptimizationLevel) {
if (OptimizationLevel > 0) {
createStandardAliasAnalysisPasses(PM);
PM->add(createCFGSimplificationPass());
PM->add(createScalarReplAggregatesPass());
PM->add(createEarlyCSEPass());
}
}
/// createStandardModulePasses - Add the standard list of module passes to the
/// provided pass manager.
///
/// \arg OptimizationLevel - The optimization level, corresponding to -O0,
/// -O1, etc.
/// \arg OptimizeSize - Whether the transformations should optimize for size.
/// \arg UnitAtATime - Allow passes which may make global module changes.
/// \arg UnrollLoops - Allow loop unrolling.
/// \arg SimplifyLibCalls - Allow library calls to be simplified.
/// \arg HaveExceptions - Whether the module may have code using exceptions.
/// \arg InliningPass - The inlining pass to use, if any, or null. This will
/// always be added, even at -O0.a
static inline void createStandardModulePasses(PassManagerBase *PM,
unsigned OptimizationLevel,
bool OptimizeSize,
bool UnitAtATime,
bool UnrollLoops,
bool SimplifyLibCalls,
bool HaveExceptions,
Pass *InliningPass) {
createStandardAliasAnalysisPasses(PM);
// If all optimizations are disabled, just run the always-inline pass.
if (OptimizationLevel == 0) {
if (InliningPass)
PM->add(InliningPass);
return;
}
if (UnitAtATime) {
PM->add(createGlobalOptimizerPass()); // Optimize out global vars
PM->add(createIPSCCPPass()); // IP SCCP
PM->add(createDeadArgEliminationPass()); // Dead argument elimination
PM->add(createInstructionCombiningPass());// Clean up after IPCP & DAE
PM->add(createCFGSimplificationPass()); // Clean up after IPCP & DAE
}
// Start of CallGraph SCC passes.
if (UnitAtATime && HaveExceptions)
PM->add(createPruneEHPass()); // Remove dead EH info
if (InliningPass)
PM->add(InliningPass);
if (UnitAtATime)
PM->add(createFunctionAttrsPass()); // Set readonly/readnone attrs
if (OptimizationLevel > 2)
PM->add(createArgumentPromotionPass()); // Scalarize uninlined fn args
// Start of function pass.
// Break up aggregate allocas, using SSAUpdater.
PM->add(createScalarReplAggregatesPass(-1, false));
PM->add(createEarlyCSEPass()); // Catch trivial redundancies
if (SimplifyLibCalls)
PM->add(createSimplifyLibCallsPass()); // Library Call Optimizations
PM->add(createJumpThreadingPass()); // Thread jumps.
PM->add(createCorrelatedValuePropagationPass()); // Propagate conditionals
PM->add(createCFGSimplificationPass()); // Merge & remove BBs
PM->add(createInstructionCombiningPass()); // Combine silly seq's
PM->add(createTailCallEliminationPass()); // Eliminate tail calls
PM->add(createCFGSimplificationPass()); // Merge & remove BBs
PM->add(createReassociatePass()); // Reassociate expressions
PM->add(createLoopRotatePass()); // Rotate Loop
PM->add(createLICMPass()); // Hoist loop invariants
PM->add(createLoopUnswitchPass(OptimizeSize || OptimizationLevel < 3));
PM->add(createInstructionCombiningPass());
PM->add(createIndVarSimplifyPass()); // Canonicalize indvars
PM->add(createLoopIdiomPass()); // Recognize idioms like memset.
PM->add(createLoopDeletionPass()); // Delete dead loops
if (UnrollLoops)
PM->add(createLoopUnrollPass()); // Unroll small loops
if (OptimizationLevel > 1)
PM->add(createGVNPass()); // Remove redundancies
PM->add(createMemCpyOptPass()); // Remove memcpy / form memset
PM->add(createSCCPPass()); // Constant prop with SCCP
// Run instcombine after redundancy elimination to exploit opportunities
// opened up by them.
PM->add(createInstructionCombiningPass());
PM->add(createJumpThreadingPass()); // Thread jumps
PM->add(createCorrelatedValuePropagationPass());
PM->add(createDeadStoreEliminationPass()); // Delete dead stores
PM->add(createAggressiveDCEPass()); // Delete dead instructions
PM->add(createCFGSimplificationPass()); // Merge & remove BBs
PM->add(createInstructionCombiningPass()); // Clean up after everything.
if (UnitAtATime) {
PM->add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
PM->add(createDeadTypeEliminationPass()); // Eliminate dead types
// GlobalOpt already deletes dead functions and globals, at -O3 try a
// late pass of GlobalDCE. It is capable of deleting dead cycles.
if (OptimizationLevel > 2)
PM->add(createGlobalDCEPass()); // Remove dead fns and globals.
if (OptimizationLevel > 1)
PM->add(createConstantMergePass()); // Merge dup global constants
}
}
static inline void addOnePass(PassManagerBase *PM, Pass *P, bool AndVerify) {
PM->add(P);
if (AndVerify)
PM->add(createVerifierPass());
}
/// createStandardLTOPasses - Add the standard list of module passes suitable
/// for link time optimization.
///
/// Internalize - Run the internalize pass.
/// RunInliner - Use a function inlining pass.
/// VerifyEach - Run the verifier after each pass.
static inline void createStandardLTOPasses(PassManagerBase *PM,
bool Internalize,
bool RunInliner,
bool VerifyEach) {
// Provide AliasAnalysis services for optimizations.
createStandardAliasAnalysisPasses(PM);
// Now that composite has been compiled, scan through the module, looking
// for a main function. If main is defined, mark all other functions
// internal.
if (Internalize)
addOnePass(PM, createInternalizePass(true), VerifyEach);
// Propagate constants at call sites into the functions they call. This
// opens opportunities for globalopt (and inlining) by substituting function
// pointers passed as arguments to direct uses of functions.
addOnePass(PM, createIPSCCPPass(), VerifyEach);
// Now that we internalized some globals, see if we can hack on them!
addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
// Linking modules together can lead to duplicated global constants, only
// keep one copy of each constant...
addOnePass(PM, createConstantMergePass(), VerifyEach);
// Remove unused arguments from functions...
addOnePass(PM, createDeadArgEliminationPass(), VerifyEach);
// Reduce the code after globalopt and ipsccp. Both can open up significant
// simplification opportunities, and both can propagate functions through
// function pointers. When this happens, we often have to resolve varargs
// calls, etc, so let instcombine do this.
addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
// Inline small functions
if (RunInliner)
addOnePass(PM, createFunctionInliningPass(), VerifyEach);
addOnePass(PM, createPruneEHPass(), VerifyEach); // Remove dead EH info.
// Optimize globals again if we ran the inliner.
if (RunInliner)
addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
addOnePass(PM, createGlobalDCEPass(), VerifyEach); // Remove dead functions.
// If we didn't decide to inline a function, check to see if we can
// transform it to pass arguments by value instead of by reference.
addOnePass(PM, createArgumentPromotionPass(), VerifyEach);
// The IPO passes may leave cruft around. Clean up after them.
addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
addOnePass(PM, createJumpThreadingPass(), VerifyEach);
// Break up allocas
addOnePass(PM, createScalarReplAggregatesPass(), VerifyEach);
// Run a few AA driven optimizations here and now, to cleanup the code.
addOnePass(PM, createFunctionAttrsPass(), VerifyEach); // Add nocapture.
addOnePass(PM, createGlobalsModRefPass(), VerifyEach); // IP alias analysis.
addOnePass(PM, createLICMPass(), VerifyEach); // Hoist loop invariants.
addOnePass(PM, createGVNPass(), VerifyEach); // Remove redundancies.
addOnePass(PM, createMemCpyOptPass(), VerifyEach); // Remove dead memcpys.
// Nuke dead stores.
addOnePass(PM, createDeadStoreEliminationPass(), VerifyEach);
// Cleanup and simplify the code after the scalar optimizations.
addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
addOnePass(PM, createJumpThreadingPass(), VerifyEach);
// Delete basic blocks, which optimization passes may have killed.
addOnePass(PM, createCFGSimplificationPass(), VerifyEach);
// Now that we have optimized the program, discard unreachable functions.
addOnePass(PM, createGlobalDCEPass(), VerifyEach);
}
}
#endif