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Use df_ext_iterator to capture the reachable set without allocating an extra set. 

Also, move large sets and vectors out of instance variables and onto the stack,
and give them more reasonable sizes.

llvm-svn: 53044
This commit is contained in:
Owen Anderson 2008-07-02 18:41:09 +00:00
parent d8ca1f6dd9
commit 488b89f608
1 changed files with 14 additions and 17 deletions
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31
llvm/lib/Transforms/Scalar/ADCE.cpp
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@ -22,10 +22,11 @@
#include "llvm/Support/CFG.h" #include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h" #include "llvm/Support/Compiler.h"
#include "llvm/Support/InstIterator.h" #include "llvm/Support/InstIterator.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h" #include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h" #include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm; using namespace llvm;
@ -36,12 +37,6 @@ namespace {
static char ID; // Pass identification, replacement for typeid static char ID; // Pass identification, replacement for typeid
ADCE() : FunctionPass((intptr_t)&ID) {} ADCE() : FunctionPass((intptr_t)&ID) {}
DenseSet<Instruction*> alive;
SmallVector<Instruction*, 1024> worklist;
DenseSet<BasicBlock*> reachable;
SmallVector<BasicBlock*, 1024> unreachable;
virtual bool runOnFunction(Function& F); virtual bool runOnFunction(Function& F);
virtual void getAnalysisUsage(AnalysisUsage& AU) const { virtual void getAnalysisUsage(AnalysisUsage& AU) const {
@ -55,15 +50,17 @@ char ADCE::ID = 0;
static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination"); static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination");
bool ADCE::runOnFunction(Function& F) { bool ADCE::runOnFunction(Function& F) {
alive.clear(); SmallPtrSet<Instruction*, 128> alive;
worklist.clear(); SmallVector<Instruction*, 128> worklist;
reachable.clear();
unreachable.clear(); SmallPtrSet<BasicBlock*, 64> reachable;
SmallVector<BasicBlock*, 16> unreachable;
// First, collect the set of reachable blocks ... // First, collect the set of reachable blocks ...
for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()), for (df_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 64> >
DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) DI = df_ext_begin(&F.getEntryBlock(), reachable),
reachable.insert(*DI); DE = df_ext_end(&F.getEntryBlock(), reachable); DI != DE; ++DI)
; // Deliberately empty, df_ext_iterator will fill in the set.
// ... and then invert it into the list of unreachable ones. These // ... and then invert it into the list of unreachable ones. These
// blocks will be removed from the function. // blocks will be removed from the function.
@ -73,7 +70,7 @@ bool ADCE::runOnFunction(Function& F) {
// Prepare to remove blocks by removing the PHI node entries for those blocks // Prepare to remove blocks by removing the PHI node entries for those blocks
// in their successors, and remove them from reference counting. // in their successors, and remove them from reference counting.
for (SmallVector<BasicBlock*, 1024>::iterator UI = unreachable.begin(), for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
UE = unreachable.end(); UI != UE; ++UI) { UE = unreachable.end(); UI != UE; ++UI) {
BasicBlock* BB = *UI; BasicBlock* BB = *UI;
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
@ -90,7 +87,7 @@ bool ADCE::runOnFunction(Function& F) {
} }
// Finally, erase the unreachable blocks. // Finally, erase the unreachable blocks.
for (SmallVector<BasicBlock*, 1024>::iterator UI = unreachable.begin(), for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
UE = unreachable.end(); UI != UE; ++UI) UE = unreachable.end(); UI != UE; ++UI)
(*UI)->eraseFromParent(); (*UI)->eraseFromParent();