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VarAction2: Remove dead stores and redundant adjusts in more cases

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This commit is contained in:
Jonathan G Rennison
2022-05-31 03:26:45 +01:00
parent 541294e845
commit e0581db2a1
1 changed files with 36 additions and 2 deletions
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38
src/newgrf.cpp
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@@ -6098,6 +6098,19 @@ static void OptimiseVarAction2DeterministicSpriteGroup(VarAction2OptimiseState &
group->ranges.clear();
}
if (!HasChickenBit(DCBF_NO_OPTIMISE_VARACT2_PRUNE) && group->ranges.empty() && !group->calculated_result) {
/* There is only one option, remove any redundant adjustments when the result will be ignored anyway */
while (!group->adjusts.empty()) {
const DeterministicSpriteGroupAdjust &prev = group->adjusts.back();
if (prev.variable != 0x7E && !IsEvalAdjustWithSideEffects(prev.operation)) {
/* Delete useless operation */
group->adjusts.pop_back();
} else {
break;
}
}
}
std::bitset<256> bits;
if (!group->calculated_result) {
auto handle_group = [&](const SpriteGroup *sg) {
@@ -6167,6 +6180,14 @@ static void HandleVarAction2DeadStoreElimination()
if (var_tracking != nullptr) bits = var_tracking->out;
for (int i = (int)group->adjusts.size() - 1; i >= 0;) {
auto restart = [&]() {
i = (int)group->adjusts.size() - 1;
if (var_tracking != nullptr) {
bits = var_tracking->out;
} else {
bits.reset();
}
};
const DeterministicSpriteGroupAdjust &adjust = group->adjusts[i];
if (adjust.operation == DSGA_OP_STO) {
if (adjust.type == DSGA_TYPE_NONE && adjust.variable == 0x1A && adjust.shift_num == 0 && adjust.and_mask < 0x100) {
@@ -6176,8 +6197,9 @@ static void HandleVarAction2DeadStoreElimination()
/* Redundant store */
group->adjusts.erase(group->adjusts.begin() + i);
i--;
if (i + 1 < (int)group->adjusts.size() && group->adjusts[i + 1].operation == DSGA_OP_RST) {
/* Now the store is elimiated, the current value has no users */
if ((i + 1 < (int)group->adjusts.size() && group->adjusts[i + 1].operation == DSGA_OP_RST) ||
(i + 1 == (int)group->adjusts.size() && group->ranges.empty() && !group->calculated_result)) {
/* Now the store is eliminated, the current value has no users */
while (i >= 0) {
const DeterministicSpriteGroupAdjust &prev = group->adjusts[i];
if (prev.variable != 0x7E && !IsEvalAdjustWithSideEffects(prev.operation)) {
@@ -6185,6 +6207,18 @@ static void HandleVarAction2DeadStoreElimination()
group->adjusts.erase(group->adjusts.begin() + i);
i--;
} else {
if (i + 1 < (int)group->adjusts.size()) {
const DeterministicSpriteGroupAdjust &next = group->adjusts[i + 1];
if (prev.operation == DSGA_OP_STO && prev.type == DSGA_TYPE_NONE && prev.variable == 0x1A &&
prev.shift_num == 0 && prev.and_mask < 0x100 &&
next.operation == DSGA_OP_RST && next.type == DSGA_TYPE_NONE && next.variable == 0x7D &&
next.parameter == prev.and_mask && next.shift_num == 0 && next.and_mask == 0xFFFFFFFF) {
/* Removing the dead store results in a store/load sequence, remove the load and re-check */
group->adjusts.erase(group->adjusts.begin() + i + 1);
restart();
break;
}
}
break;
}
}