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During MachineCopyPropagation a register may be the source operand of multiple

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copies being considered for removal. Make sure to track all of the copies,
rather than just the most recent encountered, by holding a DenseSet instead of
an unsigned in SrcMap.

No test case - couldn't reduce something with a sane size.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153487 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Lang Hames 2012-03-27 00:44:47 +00:00
parent 7067d4e4de
commit d9eb1d7797
1 changed files with 26 additions and 17 deletions
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43
lib/CodeGen/MachineCopyPropagation.cpp
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@ -22,6 +22,7 @@
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
@ -44,7 +45,7 @@ namespace {
private:
void SourceNoLongerAvailable(unsigned Reg,
DenseMap<unsigned, unsigned> &SrcMap,
DenseMap<unsigned, DenseSet<unsigned> > &SrcMap,
DenseMap<unsigned, MachineInstr*> &AvailCopyMap);
bool CopyPropagateBlock(MachineBasicBlock &MBB);
};
@ -57,24 +58,32 @@ INITIALIZE_PASS(MachineCopyPropagation, "machine-cp",
void
MachineCopyPropagation::SourceNoLongerAvailable(unsigned Reg,
DenseMap<unsigned, unsigned> &SrcMap,
DenseMap<unsigned, DenseSet<unsigned> > &SrcMap,
DenseMap<unsigned, MachineInstr*> &AvailCopyMap) {
DenseMap<unsigned, unsigned>::iterator SI = SrcMap.find(Reg);
DenseMap<unsigned, DenseSet<unsigned> >::iterator SI = SrcMap.find(Reg);
if (SI != SrcMap.end()) {
unsigned MappedDef = SI->second;
// Source of copy is no longer available for propagation.
if (AvailCopyMap.erase(MappedDef)) {
for (const uint16_t *SR = TRI->getSubRegisters(MappedDef); *SR; ++SR)
AvailCopyMap.erase(*SR);
const DenseSet<unsigned>& Defs = SI->second;
for (DenseSet<unsigned>::const_iterator I = Defs.begin(), E = Defs.end();
I != E; ++I) {
unsigned MappedDef = *I;
// Source of copy is no longer available for propagation.
if (AvailCopyMap.erase(MappedDef)) {
for (const uint16_t *SR = TRI->getSubRegisters(MappedDef); *SR; ++SR)
AvailCopyMap.erase(*SR);
}
}
}
for (const uint16_t *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
SI = SrcMap.find(*AS);
if (SI != SrcMap.end()) {
unsigned MappedDef = SI->second;
if (AvailCopyMap.erase(MappedDef)) {
for (const uint16_t *SR = TRI->getSubRegisters(MappedDef); *SR; ++SR)
AvailCopyMap.erase(*SR);
const DenseSet<unsigned>& Defs = SI->second;
for (DenseSet<unsigned>::const_iterator I = Defs.begin(), E = Defs.end();
I != E; ++I) {
unsigned MappedDef = *I;
if (AvailCopyMap.erase(MappedDef)) {
for (const uint16_t *SR = TRI->getSubRegisters(MappedDef); *SR; ++SR)
AvailCopyMap.erase(*SR);
}
}
}
}
@ -125,10 +134,10 @@ static bool isNopCopy(MachineInstr *CopyMI, unsigned Def, unsigned Src,
}
bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
SmallSetVector<MachineInstr*, 8> MaybeDeadCopies; // Candidates for deletion
DenseMap<unsigned, MachineInstr*> AvailCopyMap; // Def -> available copies map
DenseMap<unsigned, MachineInstr*> CopyMap; // Def -> copies map
DenseMap<unsigned, unsigned> SrcMap; // Src -> Def map
SmallSetVector<MachineInstr*, 8> MaybeDeadCopies; // Candidates for deletion
DenseMap<unsigned, MachineInstr*> AvailCopyMap; // Def -> available copies map
DenseMap<unsigned, MachineInstr*> CopyMap; // Def -> copies map
DenseMap<unsigned, DenseSet<unsigned> > SrcMap; // Src -> Def map
bool Changed = false;
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ) {
@ -213,7 +222,7 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
// Remember source that's copied to Def. Once it's clobbered, then
// it's no longer available for copy propagation.
SrcMap[Src] = Def;
SrcMap[Src].insert(Def);
continue;
}