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Use DenseMap instead of std::map in local register allocation. This improves the time on instcombine from .31s to .22s 

llvm-svn: 53390
This commit is contained in:
Owen Anderson 2008-07-10 01:56:35 +00:00
parent 20f41dac8d
commit 04a77c2492
1 changed files with 16 additions and 3 deletions
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19
llvm/lib/CodeGen/RegAllocLocal.cpp
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@ -25,6 +25,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Compiler.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
@ -561,13 +562,25 @@ static bool precedes(MachineBasicBlock::iterator A,
return false;
}
namespace llvm {
template<> struct DenseMapInfo<uint32_t> {
static inline uint32_t getEmptyKey() { return ~0; }
static inline uint32_t getTombstoneKey() { return ~0 - 1; }
static unsigned getHashValue(const uint32_t& Val) { return Val * 37; }
static bool isPod() { return true; }
static bool isEqual(const uint32_t& LHS, const uint32_t& RHS) {
return LHS == RHS;
}
};
}
/// ComputeLocalLiveness - Computes liveness of registers within a basic
/// block, setting the killed/dead flags as appropriate.
void RALocal::ComputeLocalLiveness(MachineBasicBlock& MBB) {
MachineRegisterInfo& MRI = MBB.getParent()->getRegInfo();
// Keep track of the most recently seen previous use or def of each reg,
// so that we can update them with dead/kill markers.
std::map<unsigned, std::pair<MachineInstr*, unsigned> > LastUseDef;
DenseMap<unsigned, std::pair<MachineInstr*, unsigned> > LastUseDef;
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
I != E; ++I) {
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
@ -586,7 +599,7 @@ void RALocal::ComputeLocalLiveness(MachineBasicBlock& MBB) {
// - A def followed by a def is dead
// - A use followed by a def is a kill
if (MO.isReg() && MO.getReg() && MO.isDef()) {
std::map<unsigned, std::pair<MachineInstr*, unsigned> >::iterator
DenseMap<unsigned, std::pair<MachineInstr*, unsigned> >::iterator
last = LastUseDef.find(MO.getReg());
if (last != LastUseDef.end()) {
// Check if this is a two address instruction. If so, then
@ -633,7 +646,7 @@ void RALocal::ComputeLocalLiveness(MachineBasicBlock& MBB) {
// Finally, loop over the final use/def of each reg
// in the block and determine if it is dead.
for (std::map<unsigned, std::pair<MachineInstr*, unsigned> >::iterator
for (DenseMap<unsigned, std::pair<MachineInstr*, unsigned> >::iterator
I = LastUseDef.begin(), E = LastUseDef.end(); I != E; ++I) {
MachineInstr* MI = I->second.first;
unsigned idx = I->second.second;