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VarAction2: Improve handling of variable 7B with a previous constant

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This commit is contained in:
Jonathan G Rennison
2022-06-10 18:02:35 +01:00
parent 23e6d861fc
commit 4f3058ee06
1 changed files with 17 additions and 21 deletions
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38
src/newgrf.cpp
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@@ -6004,6 +6004,9 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
break; break;
} }
} }
state.inference = VA2AIF_HAVE_CONSTANT;
add_inferences_from_mask(constant);
state.current_constant = constant;
if (constant != 0 || !group->adjusts.empty()) { if (constant != 0 || !group->adjusts.empty()) {
DeterministicSpriteGroupAdjust &replacement = group->adjusts.emplace_back(); DeterministicSpriteGroupAdjust &replacement = group->adjusts.emplace_back();
replacement.operation = DSGA_OP_RST; replacement.operation = DSGA_OP_RST;
@@ -6013,11 +6016,8 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
replacement.and_mask = constant; replacement.and_mask = constant;
replacement.add_val = 0; replacement.add_val = 0;
replacement.divmod_val = 0; replacement.divmod_val = 0;
state.inference = VA2AIF_PREV_MASK_ADJUST; state.inference |= VA2AIF_PREV_MASK_ADJUST;
} }
state.inference = VA2AIF_HAVE_CONSTANT;
add_inferences_from_mask(constant);
state.current_constant = constant;
}; };
auto handle_unpredictable_temp_load = [&]() { auto handle_unpredictable_temp_load = [&]() {
@@ -6050,10 +6050,19 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
} }
}; };
if (adjust.variable == 0x7B && adjust.parameter == 0x7D) handle_unpredictable_temp_load(); /* Special handling of variable 7B, this uses the parameter as the variable number, and the last value as the variable's parameter.
if (adjust.variable == 0x7B && adjust.parameter == 0x1C) { * If the last value is a known constant, it can be substituted immediately. */
adjust.variable = adjust.parameter; if (adjust.variable == 0x7B) {
adjust.parameter = 0; if (prev_inference & VA2AIF_HAVE_CONSTANT) {
adjust.variable = adjust.parameter;
adjust.parameter = state.current_constant;
} else if (adjust.parameter == 0x7D) {
handle_unpredictable_temp_load();
} else if (adjust.parameter == 0x1C) {
/* This is to simplify tracking of variable 1C, the parameter is never used for anything */
adjust.variable = adjust.parameter;
adjust.parameter = 0;
}
} }
if (adjust.variable == 0x1C && !state.seen_procedure_call) { if (adjust.variable == 0x1C && !state.seen_procedure_call) {
group->dsg_flags |= DSGF_REQUIRES_VAR1C; group->dsg_flags |= DSGF_REQUIRES_VAR1C;
@@ -6569,19 +6578,6 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
} }
add_inferences_from_mask(adjust.and_mask); add_inferences_from_mask(adjust.and_mask);
state.inference |= VA2AIF_PREV_MASK_ADJUST | VA2AIF_SINGLE_LOAD; state.inference |= VA2AIF_PREV_MASK_ADJUST | VA2AIF_SINGLE_LOAD;
if ((prev_inference & VA2AIF_PREV_MASK_ADJUST) && adjust.variable == 0x7B && group->adjusts.size() >= 2) {
const DeterministicSpriteGroupAdjust &prev = group->adjusts[group->adjusts.size() - 2];
if (prev.variable == 0x1A) {
/* Extract constant to remove indirect access via variable 7B */
DeterministicSpriteGroupAdjust current = group->adjusts.back();
current.variable = current.parameter;
current.parameter = (UINT_MAX >> prev.shift_num) & prev.and_mask;
group->adjusts.pop_back();
group->adjusts.pop_back();
group->adjusts.push_back(current);
break;
}
}
if (adjust.variable == 0x1A || adjust.and_mask == 0) { if (adjust.variable == 0x1A || adjust.and_mask == 0) {
replace_with_constant_load(EvaluateDeterministicSpriteGroupAdjust(group->size, adjust, nullptr, 0, UINT_MAX)); replace_with_constant_load(EvaluateDeterministicSpriteGroupAdjust(group->size, adjust, nullptr, 0, UINT_MAX));
} }