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VarAction2: Replace effective SMAX/SMIN sequences in DSE pass

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This commit is contained in:
Jonathan G Rennison
2022-06-08 21:19:18 +01:00
parent 0484fbf941
commit e5e984d92f
1 changed files with 51 additions and 12 deletions
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63
src/newgrf.cpp
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@@ -5733,10 +5733,22 @@ static bool IsFeatureUsableForDSE(GrfSpecFeature feature)
return (feature != GSF_STATIONS);
}
static bool IsIdenticalValueLoad(const DeterministicSpriteGroupAdjust *a, const DeterministicSpriteGroupAdjust *b)
{
if (a == nullptr && b == nullptr) return true;
if (a == nullptr || b == nullptr) return false;
if (a->variable == 0x7B || a->variable == 0x7E) return false;
return std::tie(a->type, a->variable, a->shift_num, a->parameter, a->and_mask, a->add_val, a->divmod_val) ==
std::tie(b->type, b->variable, b->shift_num, b->parameter, b->and_mask, b->add_val, b->divmod_val);
}
static const DeterministicSpriteGroupAdjust *GetVarAction2PreviousSingleLoadAdjust(const std::vector<DeterministicSpriteGroupAdjust> &adjusts, int start_index, bool *is_inverted)
{
bool passed_store_perm = false;
if (is_inverted != nullptr) *is_inverted = false;
std::bitset<256> seen_stores;
for (int i = start_index; i >= 0; i--) {
const DeterministicSpriteGroupAdjust &prev = adjusts[i];
if (prev.variable == 0x7E) {
@@ -5752,10 +5764,15 @@ static const DeterministicSpriteGroupAdjust *GetVarAction2PreviousSingleLoadAdju
/* If we passed a store perm then a load from permanent storage is not a valid previous load as we may have clobbered it */
return nullptr;
}
if (prev.variable == 0x7D && prev.parameter < 0x100 && seen_stores[prev.parameter]) {
/* If we passed a store then a load from that same store is not valid */
return nullptr;
}
return &prev;
} else if (prev.operation == DSGA_OP_STO) {
if (prev.type == DSGA_TYPE_NONE && prev.variable == 0x1A && prev.shift_num == 0 && prev.and_mask < 0x100) {
/* Temp store */
seen_stores.set(prev.and_mask, true);
continue;
} else {
/* Special register store or unpredictable store, don't try to optimise following load */
@@ -7042,19 +7059,41 @@ static std::bitset<256> HandleVarAction2DeadStoreElimination(DeterministicSprite
break;
}
}
} else if (i >= 0 && i + 1 < (int)group->adjusts.size()) {
/* See if having removed the store, there is now a useful pair of operations which can be combined */
DeterministicSpriteGroupAdjust &prev = group->adjusts[i];
DeterministicSpriteGroupAdjust &next = group->adjusts[i + 1];
if (next.type == DSGA_TYPE_NONE && next.operation == DSGA_OP_XOR && next.variable == 0x1A && next.shift_num == 0 && next.and_mask == 1) {
/* XOR: boolean invert */
if (IsEvalAdjustOperationRelationalComparison(prev.operation)) {
prev.operation = InvertEvalAdjustRelationalComparisonOperation(prev.operation);
erase_adjust(i + 1);
} else if (prev.operation == DSGA_OP_RST && IsConstantComparisonAdjustType(prev.type)) {
prev.type = InvertConstantComparisonAdjustType(prev.type);
erase_adjust(i + 1);
} else {
while (i >= 0 && i + 1 < (int)group->adjusts.size()) {
/* See if having removed the store, there is now a useful pair of operations which can be combined */
DeterministicSpriteGroupAdjust &prev = group->adjusts[i];
DeterministicSpriteGroupAdjust &next = group->adjusts[i + 1];
if (next.type == DSGA_TYPE_NONE && next.operation == DSGA_OP_XOR && next.variable == 0x1A && next.shift_num == 0 && next.and_mask == 1) {
/* XOR: boolean invert */
if (IsEvalAdjustOperationRelationalComparison(prev.operation)) {
prev.operation = InvertEvalAdjustRelationalComparisonOperation(prev.operation);
erase_adjust(i + 1);
continue;
} else if (prev.operation == DSGA_OP_RST && IsConstantComparisonAdjustType(prev.type)) {
prev.type = InvertConstantComparisonAdjustType(prev.type);
erase_adjust(i + 1);
continue;
}
}
if (i >= 1 && prev.type == DSGA_TYPE_NONE && IsEvalAdjustOperationRelationalComparison(prev.operation) &&
prev.variable == 0x1A && prev.shift_num == 0 && next.operation == DSGA_OP_MUL) {
if (((prev.operation == DSGA_OP_SGT && (prev.and_mask == 0 || prev.and_mask == (uint)-1)) || (prev.operation == DSGA_OP_SGE && (prev.and_mask == 0 || prev.and_mask == 1))) &&
IsIdenticalValueLoad(GetVarAction2PreviousSingleLoadAdjust(group->adjusts, i - 1, nullptr), &next)) {
prev.operation = DSGA_OP_SMAX;
prev.and_mask = 0;
erase_adjust(i + 1);
continue;
}
if (((prev.operation == DSGA_OP_SLE && (prev.and_mask == 0 || prev.and_mask == (uint)-1)) || (prev.operation == DSGA_OP_SLT && (prev.and_mask == 0 || prev.and_mask == 1))) &&
IsIdenticalValueLoad(GetVarAction2PreviousSingleLoadAdjust(group->adjusts, i - 1, nullptr), &next)) {
prev.operation = DSGA_OP_SMIN;
prev.and_mask = 0;
erase_adjust(i + 1);
continue;
}
}
break;
}
}
if (pending_restart) restart();