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

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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 0b0017e514
commit 9a7d657786
1 changed files with 14 additions and 17 deletions
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31
lib/Transforms/Scalar/ADCE.cpp
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@ -22,10 +22,11 @@
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
@ -36,12 +37,6 @@ namespace {
static char ID; // Pass identification, replacement for typeid
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 void getAnalysisUsage(AnalysisUsage& AU) const {
@ -55,15 +50,17 @@ char ADCE::ID = 0;
static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination");
bool ADCE::runOnFunction(Function& F) {
alive.clear();
worklist.clear();
reachable.clear();
unreachable.clear();
SmallPtrSet<Instruction*, 128> alive;
SmallVector<Instruction*, 128> worklist;
SmallPtrSet<BasicBlock*, 64> reachable;
SmallVector<BasicBlock*, 16> unreachable;
// First, collect the set of reachable blocks ...
for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
DE = df_end(&F.getEntryBlock()); DI != DE; ++DI)
reachable.insert(*DI);
for (df_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 64> >
DI = df_ext_begin(&F.getEntryBlock(), reachable),
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
// 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
// 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) {
BasicBlock* BB = *UI;
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.
for (SmallVector<BasicBlock*, 1024>::iterator UI = unreachable.begin(),
for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
UE = unreachable.end(); UI != UE; ++UI)
(*UI)->eraseFromParent();