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Simplify DCE code a lot
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1079 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -34,33 +34,12 @@
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#include "llvm/Assembly/Writer.h"
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#include <algorithm>
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struct ConstPoolDCE {
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enum { EndOffs = 0 };
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static bool isDCEable(const ConstPoolVal *CPV) {
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// TODO: The bytecode writer requires that all used types are in the
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// constant pool for the current method. This is messy and is really
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// irritating. FIXME
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return CPV->getType() != Type::TypeTy; // Don't DCE Type plane constants!
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}
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};
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struct BasicBlockDCE {
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enum { EndOffs = 1 };
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static bool isDCEable(const Instruction *I) {
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return !I->hasSideEffects();
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}
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};
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template<class Container, class DCEController>
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static bool RemoveUnusedDefs(Container &Vals, DCEController DCEControl) {
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static bool RemoveUnusedDefs(BasicBlock::InstListType &Vals) {
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bool Changed = false;
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int Offset = DCEController::EndOffs;
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for (typename Container::iterator DI = Vals.begin();
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DI != Vals.end()-Offset; ) {
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for (BasicBlock::InstListType::iterator DI = Vals.begin();
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DI != Vals.end()-1; ) {
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// Look for un"used" definitions...
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if ((*DI)->use_empty() && DCEController::isDCEable(*DI)) {
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if ((*DI)->use_empty() && !(*DI)->hasSideEffects()) {
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// Bye bye
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//cerr << "Removing: " << *DI;
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delete Vals.remove(DI);
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@ -272,7 +251,7 @@ static bool DoDCEPass(Method *M) {
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// Loop through now and remove instructions that have no uses...
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for (BBIt = M->begin(); BBIt != BBEnd; ++BBIt) {
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Changed |= RemoveUnusedDefs((*BBIt)->getInstList(), BasicBlockDCE());
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Changed |= RemoveUnusedDefs((*BBIt)->getInstList());
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Changed |= RemoveSingularPHIs(*BBIt);
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}
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