VarAction2: Add adjust types for combined (in)equality with constant

src/newgrf.cpp

@@ -5896,6 +5896,17 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
 							prev.operation = DSGA_OP_EQ;
 							group->adjusts.pop_back();
 							state.inference = VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO;
+							if (group->adjusts.size() >= 2) {
+								DeterministicSpriteGroupAdjust &eq_adjust = group->adjusts[group->adjusts.size() - 1];
+								DeterministicSpriteGroupAdjust &prev_op = group->adjusts[group->adjusts.size() - 2];
+								if (eq_adjust.type == DSGA_TYPE_NONE && eq_adjust.variable == 0x1A &&
+										prev_op.type == DSGA_TYPE_NONE && prev_op.operation == DSGA_OP_RST) {
+									prev_op.type = DSGA_TYPE_EQ;
+									prev_op.add_val = (0xFFFFFFFF >> eq_adjust.shift_num) & eq_adjust.and_mask;
+									group->adjusts.pop_back();
+									state.inference |= VA2AIF_SINGLE_LOAD;
+								}
+							}
 							break;
 						}
 						if (prev_inference & VA2AIF_ONE_OR_ZERO) {
@@ -5931,6 +5942,12 @@ static void OptimiseVarAction2Adjust(VarAction2OptimiseState &state, const GrfSp
 							state.inference = VA2AIF_PREV_TERNARY;
 							break;
 						}
+						if (prev.operation == DSGA_OP_RST && (prev.type == DSGA_TYPE_EQ || prev.type == DSGA_TYPE_NEQ)) {
+							prev.type = (prev.type == DSGA_TYPE_EQ) ? DSGA_TYPE_NEQ : DSGA_TYPE_EQ;
+							group->adjusts.pop_back();
+							state.inference = VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO | VA2AIF_SINGLE_LOAD;
+							break;
+						}
 					}
 					if (adjust.and_mask <= 1) state.inference = prev_inference & (VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO);
 					break;

src/newgrf_spritegroup.cpp

@@ -157,6 +157,8 @@ static U EvalAdjustT(const DeterministicSpriteGroupAdjust &adjust, ScopeResolver
 	switch (adjust.type) {
 		case DSGA_TYPE_DIV:  value = ((S)value + (S)adjust.add_val) / (S)adjust.divmod_val; break;
 		case DSGA_TYPE_MOD:  value = ((S)value + (S)adjust.add_val) % (S)adjust.divmod_val; break;
+		case DSGA_TYPE_EQ:   value = (value == adjust.add_val) ? 1 : 0; break;
+		case DSGA_TYPE_NEQ:  value = (value != adjust.add_val) ? 1 : 0; break;
 		case DSGA_TYPE_NONE: break;
 	}
 
@@ -765,7 +767,9 @@ void SpriteGroupDumper::DumpSpriteGroup(const SpriteGroup *sg, int padding, uint
 				p += seprintf(p, lastof(this->buffer), ", shift: %X, and: %X", adjust.shift_num, adjust.and_mask);
 				switch (adjust.type) {
 					case DSGA_TYPE_DIV: p += seprintf(p, lastof(this->buffer), ", add: %X, div: %X", adjust.add_val, adjust.divmod_val); break;
-					case DSGA_TYPE_MOD:  p += seprintf(p, lastof(this->buffer), ", add: %X, mod: %X", adjust.add_val, adjust.divmod_val); break;
+					case DSGA_TYPE_MOD: p += seprintf(p, lastof(this->buffer), ", add: %X, mod: %X", adjust.add_val, adjust.divmod_val); break;
+					case DSGA_TYPE_EQ:  p += seprintf(p, lastof(this->buffer), ", eq: %X", adjust.add_val); break;
+					case DSGA_TYPE_NEQ: p += seprintf(p, lastof(this->buffer), ", neq: %X", adjust.add_val); break;
 					case DSGA_TYPE_NONE: break;
 				}
 				p += seprintf(p, lastof(this->buffer), ", op: %X (%s)", adjust.operation, GetAdjustOperationName(adjust.operation));

src/newgrf_spritegroup.h

@@ -146,6 +146,9 @@ enum DeterministicSpriteGroupAdjustType {
 	DSGA_TYPE_NONE,
 	DSGA_TYPE_DIV,
 	DSGA_TYPE_MOD,
+
+	DSGA_TYPE_EQ,
+	DSGA_TYPE_NEQ,
 };
 
 enum DeterministicSpriteGroupAdjustOperation {