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VarAction2: Detect and replace reversed commutative op via temp storage

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This commit is contained in:
Jonathan G Rennison
2022-05-29 11:59:03 +01:00
parent 762cfb3df7
commit 1fec7d6ddb
2 changed files with 30 additions and 1 deletions
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17
src/newgrf.cpp
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@@ -5671,6 +5671,20 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
/* Operation always returns 0, replace it and any useless prior operations */
replace_with_constant_load(0);
} else {
if (adjust.variable == 0x7D && adjust.shift_num == 0 && adjust.and_mask == get_full_mask() && IsEvalAdjustOperationCommutative(adjust.operation)) {
DeterministicSpriteGroupAdjust &prev = group->adjusts[group->adjusts.size() - 2];
if (group->adjusts.size() >= 3 && prev.operation == DSGA_OP_RST) {
const DeterministicSpriteGroupAdjust &prev2 = group->adjusts[group->adjusts.size() - 3];
if (prev2.operation == DSGA_OP_STO && prev2.type == DSGA_TYPE_NONE && prev2.variable == 0x1A &&
prev2.shift_num == 0 && prev2.and_mask == adjust.parameter) {
/* Convert: store, load var, commutative op on stored --> (dead) store, commutative op var */
prev.operation = adjust.operation;
group->adjusts.pop_back();
OptimiseVarAction2Adjust(state, feature, varsize, group, group->adjusts.back());
return;
}
}
}
switch (adjust.operation) {
case DSGA_OP_SUB:
if (adjust.variable == 0x7D && adjust.shift_num == 0 && adjust.and_mask == 0xFFFFFFFF) {
@@ -5682,7 +5696,8 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
/* Convert: store, load var, subtract stored --> (dead) store, reverse subtract var */
prev.operation = DSGA_OP_RSUB;
group->adjusts.pop_back();
break;
OptimiseVarAction2Adjust(state, feature, varsize, group, group->adjusts.back());
return;
}
}
}