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Fixed N flag thrashing due to cross block value forwarding

This commit is contained in:
drmortalwombat 2021-11-27 23:33:03 +01:00
parent 730fb7513e
commit 2003f2f4fd
2 changed files with 21 additions and 7 deletions
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26
oscar64/NativeCodeGenerator.cpp
View File

@ -8539,7 +8539,7 @@ bool NativeCodeBasicBlock::MoveLoadAddZPStoreUp(int at)
return false;
}
bool NativeCodeBasicBlock::ValueForwarding(const NativeRegisterDataSet& data)
bool NativeCodeBasicBlock::ValueForwarding(const NativeRegisterDataSet& data, bool global)
{
bool changed = false;
@ -8547,7 +8547,7 @@ bool NativeCodeBasicBlock::ValueForwarding(const NativeRegisterDataSet& data)
{
mNDataSet = data;
if (mLoopHead)
if (mLoopHead || !global)
{
mNDataSet.Reset();
}
@ -8677,9 +8677,9 @@ bool NativeCodeBasicBlock::ValueForwarding(const NativeRegisterDataSet& data)
}
}
#endif
if (this->mTrueJump && this->mTrueJump->ValueForwarding(mNDataSet))
if (this->mTrueJump && this->mTrueJump->ValueForwarding(mNDataSet, global))
changed = true;
if (this->mFalseJump && this->mFalseJump->ValueForwarding(mNDataSet))
if (this->mFalseJump && this->mFalseJump->ValueForwarding(mNDataSet, global))
changed = true;
}
@ -9727,6 +9727,7 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(int pass)
// Replace (a & 0x80) != 0 with bpl/bmi
int sz = mIns.Size();
#if 1
if (sz > 1 &&
mIns[sz - 2].ChangesAccuAndFlag() &&
mIns[sz - 1].mType == ASMIT_AND && mIns[sz - 1].mMode == ASMIM_IMMEDIATE && mIns[sz - 1].mAddress == 0x80 && !(mIns[sz - 1].mLive & LIVE_CPU_REG_A))
@ -9746,7 +9747,7 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(int pass)
changed = true;
}
}
#endif
if (sz > 4 &&
mIns[sz - 4].mType == ASMIT_ASL && mIns[sz - 4].mMode == ASMIM_IMPLIED &&
mIns[sz - 3].mType == ASMIT_LDA && mIns[sz - 3].mMode == ASMIM_IMMEDIATE && mIns[sz - 3].mAddress == 0 &&
@ -10154,12 +10155,21 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(int pass)
{
mIns.Insert(i + 2, NativeCodeInstruction(ASMIT_LDY, ASMIM_IMMEDIATE, mIns[i + 0].mAddress));
mIns[i + 2].mLive |= LIVE_CPU_REG_Y;
if (mIns[i + 1].mLive & LIVE_CPU_REG_Z)
{
mIns.Insert(i + 3, NativeCodeInstruction(ASMIT_ORA, ASMIM_IMMEDIATE, 0));
mIns[i + 3].mLive |= LIVE_CPU_REG_Y | LIVE_CPU_REG_Z;
}
}
if (iins || (flags & LIVE_CPU_REG_Y))
{
mIns[i + 1].mMode = ASMIM_ABSOLUTE_Y;
}
else
{
mIns[i + 1].mMode = ASMIM_ABSOLUTE_X;
}
mIns[i + 1].mLinkerObject = ains->mLinkerObject;
mIns[i + 1].mAddress = ains->mAddress + mIns[i + 0].mAddress;
@ -10170,11 +10180,15 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(int pass)
{
mIns.Insert(apos, NativeCodeInstruction(ASMIT_TAY, ASMIM_IMPLIED));
mIns[apos].mLive = LIVE_CPU_REG_Y | LIVE_CPU_REG_A;
for (int j = apos; j < i + 2; j++)
mIns[j].mLive |= LIVE_CPU_REG_Y;
}
else
{
mIns.Insert(apos, NativeCodeInstruction(ASMIT_TAX, ASMIM_IMPLIED));
mIns[apos].mLive = LIVE_CPU_REG_X | LIVE_CPU_REG_A;
for (int j = apos; j < i + 2; j++)
mIns[j].mLive |= LIVE_CPU_REG_X;
}
}
else if (iins->mMode != ASMIM_ZERO_PAGE)
@ -11558,7 +11572,7 @@ void NativeCodeProcedure::Optimize(void)
ResetVisited();
NativeRegisterDataSet data;
if (mEntryBlock->ValueForwarding(data))
if (mEntryBlock->ValueForwarding(data, step > 0))
changed = true;
} while (changed);

2
oscar64/NativeCodeGenerator.h
View File

@ -188,7 +188,7 @@ public:
bool MoveStoreHighByteDown(int at);
bool MoveAddHighByteDown(int at);
bool ValueForwarding(const NativeRegisterDataSet& data);
bool ValueForwarding(const NativeRegisterDataSet& data, bool global);
void CollectEntryBlocks(NativeCodeBasicBlock* block);