diff --git a/lib/CodeGen/PostOpts/Makefile b/lib/CodeGen/PostOpts/Makefile new file mode 100644 index 00000000000..5d1242ca9d8 --- /dev/null +++ b/lib/CodeGen/PostOpts/Makefile @@ -0,0 +1,9 @@ +LEVEL = ../../.. + +DIRS = + +LIBRARYNAME = postopts + +BUILD_ARCHIVE = 1 + +include $(LEVEL)/Makefile.common diff --git a/lib/Target/SparcV9/SparcV9PeepholeOpts.cpp b/lib/Target/SparcV9/SparcV9PeepholeOpts.cpp new file mode 100644 index 00000000000..ee749efe8eb --- /dev/null +++ b/lib/Target/SparcV9/SparcV9PeepholeOpts.cpp @@ -0,0 +1,136 @@ +// $Id$ -*-c++-*- +//*************************************************************************** +// File: +// PeepholeOpts.h +// +// Purpose: +// Support for performing several peephole opts in one or a few passes +// over the machine code of a method. +//**************************************************************************/ + + +#include "llvm/CodeGen/PeepholeOpts.h" +#include "llvm/CodeGen/MachineCodeForBasicBlock.h" +#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/MachineInstrInfo.h" +#include "llvm/Target/MachineOptInfo.h" +#include "llvm/BasicBlock.h" +#include "llvm/Pass.h" + + +//********************* Internal Class Declarations ************************/ + + +//************************* Internal Functions *****************************/ + +inline void +DeleteInstruction(MachineCodeForBasicBlock& mvec, + MachineCodeForBasicBlock::iterator& BBI, + const TargetMachine& target) +{ + // Check if this instruction is in a delay slot of its predecessor. + // If so, replace this instruction with a nop, else just delete it. + // By replacing in place, we save having to update the I-I maps. + if (BBI != mvec.begin()) + { + const MachineInstrInfo& mii = target.getInstrInfo(); + MachineInstr* predMI = *(BBI-1); + if (unsigned ndelay = mii.getNumDelaySlots(predMI->getOpCode())) + { + assert(ndelay == 1 && "Not yet handling multiple-delay-slot targets"); + (*BBI)->replace(mii.getNOPOpCode(), 0); + } + } + else + { + mvec.erase(BBI); + BBI = mvec.end(); + } +} + +//******************* Individual Peephole Optimizations ********************/ + + +inline bool +RemoveUselessCopies(MachineCodeForBasicBlock& mvec, + MachineCodeForBasicBlock::iterator& BBI, + const TargetMachine& target) +{ + if (target.getOptInfo().IsUselessCopy(*BBI)) + { + DeleteInstruction(mvec, BBI, target); + return true; + } + return false; +} + + +//************************ Class Implementations **************************/ + +class PeepholeOpts: public BasicBlockPass { + const TargetMachine ⌖ + bool visit(MachineCodeForBasicBlock& mvec, + MachineCodeForBasicBlock::iterator BBI) const; +public: + PeepholeOpts(const TargetMachine &T): target(T) { } + bool runOnBasicBlock(BasicBlock &BB); // apply this pass to each BB +}; + + +// Register the pass with llc only, and not opt... +static RegisterLLC +X("peephole", "Peephole Optimization", createPeepholeOptsPass); + + +/* Apply a list of peephole optimizations to this machine instruction + * within its local context. They are allowed to delete MI or any + * instruction before MI, but not + */ +bool +PeepholeOpts::visit(MachineCodeForBasicBlock& mvec, + MachineCodeForBasicBlock::iterator BBI) const +{ + bool changed = false; + + /* Remove redundant copy instructions */ + changed |= RemoveUselessCopies(mvec, BBI, target); + if (BBI == mvec.end()) // nothing more to do! + return changed; + + return changed; +} + + +bool +PeepholeOpts::runOnBasicBlock(BasicBlock &BB) +{ + // Get the machine instructions for this BB + MachineCodeForBasicBlock& mvec = MachineCodeForBasicBlock::get(&BB); + + // Iterate over all machine instructions in the BB + // Use a reverse iterator to allow deletion of MI or any instruction after it. + // Insertions or deletions *before* MI are not safe. + // + for (MachineCodeForBasicBlock::reverse_iterator RI=mvec.rbegin(), + RE=mvec.rend(); RI != RE; ) + { + MachineCodeForBasicBlock::iterator BBI = RI.base()-1; // save before incr + ++RI; // pre-increment to delete MI or after it + visit(mvec, BBI); + } + + return true; +} + + +//===----------------------------------------------------------------------===// +// createPeepholeOptsPass - Public entrypoint for peephole optimization +// and this file as a whole... +// +Pass* +createPeepholeOptsPass(TargetMachine &T) +{ + return new PeepholeOpts(T); +} +