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Merged
Frotty merged 1 commit into from
Sep 5, 2026
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Merged

Fuse tuple field assignments #1299

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7 changes: 2 additions & 5 deletions ...tscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/EliminateTuples.java
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Original file line number Diff line number Diff line change
Expand Up @@ -580,17 +580,14 @@ public void visit(ImMethodCall mc) {
/**
* Select tuple storage before expanding it. Expanding first turns one array/member read into
* reads of every scalar backing variable, which then have to be preserved through discard
* calls because those reads can fail. A source-level field read only needs the selected
* backing component.
* calls because those reads can fail. A source-level field read or write only needs the
* selected backing component.
*/
private static @org.eclipse.jdt.annotation.Nullable ImExpr selectTupleStorageComponent(
ImTupleSelection selection, ImTranslator translator, ImFunction f) {
List<Integer> componentPath = new ArrayList<>();
ImExpr storage = selection;
while (storage instanceof ImTupleSelection current) {
if (current.isUsedAsLValue()) {
return null;
}
componentPath.add(current.getTupleIndex());
storage = current.getTupleExpr();
}
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89 changes: 89 additions & 0 deletions de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/LuaBackendAuditTests.java
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Expand Up @@ -282,6 +282,95 @@ public void tupleFieldReadsOnlyLoadTheSelectedStorageComponent() throws IOExcept
|| memberRead.contains("__wurst_tuple_discard_"));
}

@Test
public void tupleFieldAssignmentsOnlyTouchTheSelectedStorageComponent() throws IOException {
String[] source = {
"package Test",
"native testSuccess()",
"tuple vec3(real x, real y, real z)",
"tuple segment(vec3 start, vec3 finish)",
"vec3 array points",
"segment array segments",
"int indexCalls",
"int trace",
"@noinline function nextIndex() returns int",
" indexCalls++",
" trace = trace * 10 + 1",
" return 2",
"@noinline function nextValue() returns real",
" trace = trace * 10 + 2",
" return 21.",
"@noinline function setAt(int index, real value)",
" points[index].z = value",
"@noinline function setAtNext()",
" points[nextIndex()].y = nextValue()",
"@noinline function addAt(int index, real value)",
" points[index].x += value",
"@noinline function setNested(int index, real value)",
" segments[index].finish.y = value",
"@noinline function replaceAt(int index, vec3 value)",
" points[index] = value",
"class Entity",
" vec3 pos",
"@noinline function setPos(Entity entity, real value)",
" entity.pos.z = value",
"init",
" points[1] = vec3(1., 2., 3.)",
" points[2] = vec3(4., 5., 6.)",
" segments[1] = segment(vec3(7., 8., 9.), vec3(10., 11., 12.))",
" let entity = new Entity()",
" entity.pos = vec3(13., 14., 15.)",
" setAt(1, 20.)",
" setAtNext()",
" addAt(1, 22.)",
" setNested(1, 23.)",
" setPos(entity, 24.)",
" replaceAt(2, vec3(25., 26., 27.))",
" if points[1] == vec3(23., 2., 20.) and points[2] == vec3(25., 26., 27.)",
" and segments[1] == segment(vec3(7., 8., 9.), vec3(10., 23., 12.))",
" and entity.pos == vec3(13., 14., 24.) and indexCalls == 1 and trace == 12",
" testSuccess()"
};
test().testLua(true).executeProg().lines(source);

String compiled = compileOptimizedLua(
"tupleFieldAssignmentsOnlyTouchTheSelectedStorageComponentOptimized", source);
String plainWrite = luaFunctionBody(compiled, "setAt");
String effectfulWrite = luaFunctionBody(compiled, "setAtNext");
String readModifyWrite = luaFunctionBody(compiled, "addAt");
String nestedWrite = luaFunctionBody(compiled, "setNested");
String memberWrite = luaFunctionBody(compiled, "setPos");
String wholeTupleWrite = luaFunctionBody(compiled, "replaceAt");

assertTrue(plainWrite.contains("points_z["));
assertFalse(plainWrite.contains("points_x["));
assertFalse(plainWrite.contains("points_y["));
assertTrue(effectfulWrite.contains("points_y["));
assertFalse(effectfulWrite.contains("points_x["));
assertFalse(effectfulWrite.contains("points_z["));
assertEquals("a selected tuple-array field must evaluate its write index exactly once",
1, effectfulWrite.split("nextIndex\\(", -1).length - 1);
assertTrue(readModifyWrite.contains("points_x["));
assertFalse(readModifyWrite.contains("points_y["));
assertFalse(readModifyWrite.contains("points_z["));
assertTrue(nestedWrite.contains("segments_finish_y["));
assertFalse(nestedWrite.contains("segments_start_"));
assertFalse(nestedWrite.contains("segments_finish_x["));
assertFalse(nestedWrite.contains("segments_finish_z["));
assertTrue(memberWrite.contains("Entity_pos_z_storage["));
assertFalse(memberWrite.contains("Entity_pos_x_storage["));
assertFalse(memberWrite.contains("Entity_pos_y_storage["));
assertTrue("whole-tuple assignment must still write x", wholeTupleWrite.contains("points_x["));
assertTrue("whole-tuple assignment must still write y", wholeTupleWrite.contains("points_y["));
assertTrue("whole-tuple assignment must still write z", wholeTupleWrite.contains("points_z["));
assertFalse("selected tuple storage writes must not need discard helpers",
plainWrite.contains("__wurst_tuple_discard_")
|| effectfulWrite.contains("__wurst_tuple_discard_")
|| readModifyWrite.contains("__wurst_tuple_discard_")
|| nestedWrite.contains("__wurst_tuple_discard_")
|| memberWrite.contains("__wurst_tuple_discard_"));
}

@Test
public void tupleMemberArrayAssignmentCapturesIndex() throws IOException {
test().testLua(true).luaOnly(false).executeProg().lines(
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