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Decide a loop pass's dead back edge with a walk converging nested loops when the body is not replayable #6811

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Decide a loop pass's dead back edge with a walk converging nested loops when the body is not replayable #6811

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5 changes: 5 additions & 0 deletions src/Analyser/StmtHandler/DoWhileHandler.php
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Expand Up @@ -95,6 +95,11 @@ public function processStmt(
$previousPass = $passRecord;
$previousPassStorage = $storage;
$backEdgeScope = $bodyScopeResult->getLoopBackEdgeScope();
if ($backEdgeScope === null && !$bodyIsReplayable) {
// a nested loop walks only its first iteration in a pass - its unconverged
// types can make the back edge look dead, so a walk converging it decides
$backEdgeScope = $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $bodyScope, $storage->duplicate(), new NoopNodeCallback(), $context->withoutTemplateArgumentResolution())->filterOutLoopExitPoints()->getLoopBackEdgeScope();
}
$finalScope = $backEdgeScope === null ? $finalScope : $backEdgeScope->mergeWith($finalScope);
foreach ($bodyScopeResult->getExitPointsByType(Break_::class) as $breakExitPoint) {
$finalScope = $breakExitPoint->getScope()->mergeWith($finalScope);
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6 changes: 6 additions & 0 deletions src/Analyser/StmtHandler/ForHandler.php
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Expand Up @@ -202,6 +202,7 @@ public function processStmt(
// entry state differs from the previous pass's (StatementsHandler::processLoopPassStmtNodes())
$previousPass = null;
$previousPassStorage = null;
$bodyIsReplayable = $nodeScopeResolver->isReplayableConvergenceBody($stmt, $stmt->stmts);
do {
$prevScope = $bodyScope;
$storage = $originalStorage->duplicate();
Expand Down Expand Up @@ -231,6 +232,11 @@ public function processStmt(
$previousPassStorage = $storage;
$passFlows[] = $bodyScopeResult->getVariableFlow();
$backEdgeScope = $bodyScopeResult->getLoopBackEdgeScope();
if ($backEdgeScope === null && !$bodyIsReplayable) {
// a nested loop walks only its first iteration in a pass - its unconverged
// types can make the back edge look dead, so a walk converging it decides
$backEdgeScope = $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $bodyScope, $storage->duplicate(), new NoopNodeCallback(), $context->withoutTemplateArgumentResolution())->filterOutLoopExitPoints()->getLoopBackEdgeScope();
}
if ($backEdgeScope === null) {
$bodyScope = $prevScope;
break;
Expand Down
10 changes: 10 additions & 0 deletions src/Analyser/StmtHandler/ForeachHandler.php
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Expand Up @@ -254,6 +254,11 @@ static function () use ($condResult, $emptyArrayType): Type {
$previousPass = $passRecord;
$previousPassStorage = $storage;
$backEdgeScope = $bodyScopeResult->getLoopBackEdgeScope();
if ($backEdgeScope === null && !$bodyIsReplayable) {
// a nested loop walks only its first iteration in a pass - its unconverged
// types can make the back edge look dead, so a walk converging it decides
$backEdgeScope = $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $bodyScope, $storage->duplicate(), new NoopNodeCallback(), $context->withoutTemplateArgumentResolution())->filterOutLoopExitPoints()->getLoopBackEdgeScope();
}
if ($backEdgeScope === null) {
$bodyScope = $prevScope;
break;
Expand Down Expand Up @@ -868,6 +873,11 @@ private function tryProcessUnrolledConstantArrayForeach(
$iterBodyScope = $this->enterForeach($nodeScopeResolver, $iterBodyScope, $iterStorage, $originalScope, $stmt, $iterateeType, $nativeIterateeType, new NoopNodeCallback());
$iterBodyScopeResult = $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $iterBodyScope, $iterStorage, new NoopNodeCallback(), $context->enterDeep()->withoutTemplateArgumentResolution())->filterOutLoopExitPoints();
$backEdgeScope = $iterBodyScopeResult->getLoopBackEdgeScope();
if ($backEdgeScope === null && !$nodeScopeResolver->isReplayableConvergenceBody($stmt, $stmt->stmts)) {
// a nested loop walks only its first iteration in a pass - its unconverged
// types can make the back edge look dead, so a walk converging it decides
$backEdgeScope = $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $iterBodyScope, $iterStorage->duplicate(), new NoopNodeCallback(), $context->withoutTemplateArgumentResolution())->filterOutLoopExitPoints()->getLoopBackEdgeScope();
}
foreach ($iterBodyScopeResult->getExitPointsByType(Break_::class) as $breakExitPoint) {
$endScope = $endScope->mergeWith($breakExitPoint->getScope());
}
Expand Down
5 changes: 5 additions & 0 deletions src/Analyser/StmtHandler/WhileHandler.php
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Expand Up @@ -123,6 +123,11 @@ public function processStmt(
$previousPass = $passRecord;
$previousPassStorage = $storage;
$backEdgeScope = $bodyScopeResult->getLoopBackEdgeScope();
if ($backEdgeScope === null && !$bodyIsReplayable) {
// a nested loop walks only its first iteration in a pass - its unconverged
// types can make the back edge look dead, so a walk converging it decides
$backEdgeScope = $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $bodyScope, $storage->duplicate(), new NoopNodeCallback(), $context->withoutTemplateArgumentResolution())->filterOutLoopExitPoints()->getLoopBackEdgeScope();
}
} finally {
$scope->popExpressionResultStorage();
}
Expand Down
180 changes: 180 additions & 0 deletions tests/PHPStan/Analyser/nsrt/bug-15420.php
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@@ -0,0 +1,180 @@
<?php declare(strict_types = 1);

namespace Bug15420;

use function PHPStan\Testing\assertType;

class Test {
/** @param string[] $cards */
public function f(array $cards): void
{
for ($i = 0; $i < 10; $i++) {
$seen = [];
$later = [];
foreach ($cards as $card) {
if (array_key_exists($card, $seen)) {
$later[] = $card;
continue;
}
$seen[$card] = true;
}
assertType('int<0, 9>', $i);
if ($later !== []) {
$cards = $later;
} else {
break;
}
}
}
}

/** @param string[] $cards */
function whileLoop(array $cards): void
{
$i = 0;
while ($i < 10) {
$seen = [];
$later = [];
foreach ($cards as $card) {
if (array_key_exists($card, $seen)) {
$later[] = $card;
}
$seen[$card] = true;
}
if ($later === []) {
break;
}
assertType('int<0, 9>', $i);
$i++;
}
}

/** @param string[] $cards */
function doWhileLoop(array $cards): void
{
$i = 0;
do {
$seen = [];
$later = [];
foreach ($cards as $card) {
if (array_key_exists($card, $seen)) {
$later[] = $card;
}
$seen[$card] = true;
}
if ($later === []) {
break;
}
assertType('int<0, max>', $i);
$i++;
} while ($i < 10);
}

/**
* @param string[] $cards
* @param int[] $rounds
*/
function foreachLoop(array $cards, array $rounds): void
{
$i = 0;
foreach ($rounds as $round) {
$seen = [];
$later = [];
foreach ($cards as $card) {
if (array_key_exists($card, $seen)) {
$later[] = $card;
}
$seen[$card] = true;
}
if ($later === []) {
break;
}
assertType('int<0, max>', $i);
$i++;
}
}

/**
* @param string[] $cards
* @param array{a: int, b: int, ...<string, int>} $rounds
*/
function unsealedConstantArrayForeachLoop(array $cards, array $rounds): void
{
$i = 0;
foreach ($rounds as $round) {
$seen = [];
$later = [];
foreach ($cards as $card) {
if (array_key_exists($card, $seen)) {
$later[] = $card;
}
$seen[$card] = true;
}
if ($later === []) {
break;
}
assertType('int<0, max>', $i);
$i++;
}
}

/** @param string[] $cards */
function innerWhile(array $cards): void
{
for ($i = 0; $i < 10; $i++) {
$seen = false;
$later = false;
$j = 0;
while ($j < count($cards)) {
if ($seen) {
$later = true;
}
$seen = true;
$j++;
}
if (!$later) {
break;
}
assertType('int<0, 9>', $i);
}
}

/** @param string[] $cards */
function innerFor(array $cards): void
{
for ($i = 0; $i < 10; $i++) {
$seen = false;
$later = false;
for ($j = 0; $j < count($cards); $j++) {
if ($seen) {
$later = true;
}
$seen = true;
}
if (!$later) {
break;
}
assertType('int<0, 9>', $i);
}
}

/** @param string[] $cards */
function innerDoWhile(array $cards): void
{
for ($i = 0; $i < 10; $i++) {
$seen = false;
$later = false;
$j = 0;
do {
if ($seen) {
$later = true;
}
$seen = true;
$j++;
} while ($j < count($cards));
if (!$later) {
break;
}
assertType('int<0, 9>', $i);
}
}
5 changes: 5 additions & 0 deletions tests/PHPStan/Rules/Comparison/NumberComparisonOperatorsConstantConditionRuleTest.php
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Expand Up @@ -326,6 +326,11 @@ public function testBug15243(): void
$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-15243.php'], []);
}

public function testBug15420(): void
{
$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-15420.php'], []);
}

public function testShiftLeftUnboundedRange(): void
{
$this->analyse([__DIR__ . '/../../Analyser/nsrt/shift-left-unbounded-range.php'], []);
Expand Down
4 changes: 4 additions & 0 deletions turbo-ext/src/DoWhileHandler.cpp
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Expand Up @@ -130,6 +130,10 @@ class DoWhileHandler
if (UNEXPECTED(bodyScopeResult.isUndef())) return;
zv::Val backEdgeScope = pt_internal_statement_result_loop_back_edge_scope(bodyScopeResult.raw());
if (UNEXPECTED(backEdgeScope.isUndef())) return;
if (backEdgeScope.isNull() && !bodyIsReplayable) {
backEdgeScope = ptlh::convergedPassBackEdgeScope(nodeScopeResolver, stmt, stmtsHold.raw(), bodyScope.raw(), storage.raw(), context);
if (UNEXPECTED(backEdgeScope.isUndef())) return;
}
if (!backEdgeScope.isNull()) {
if (UNEXPECTED(!ptlh::otherMergeWith(backEdgeScope.raw(), finalScope))) return;
}
Expand Down
10 changes: 10 additions & 0 deletions turbo-ext/src/ForHandler.cpp
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Expand Up @@ -219,6 +219,12 @@ class ForHandler
// entry state differs from the previous pass's (StatementsHandler::processLoopPassStmtNodes())
zv::Val previousPass = zv::Val::null();
zv::Val previousPassStorage = zv::Val::null();
bool bodyIsReplayable;
{
zval *bodyStmts = ptsh::readNodeProperty(pt_fh_stmts_site, stmt, PT_LC("stmts"));
if (UNEXPECTED(bodyStmts == NULL)) return zv::Val();
if (UNEXPECTED(!pt_node_scope_resolver_is_replayable_convergence_body(nodeScopeResolver, stmt, bodyStmts, bodyIsReplayable))) return zv::Val();
}
do {
zv::Val prevScope = zv::Val::copyOf(bodyScope.ref());
zv::Val storage = pt_expression_result_storage_duplicate(originalStorage);
Expand Down Expand Up @@ -279,6 +285,10 @@ class ForHandler
}
zv::Val backEdgeScope = pt_internal_statement_result_loop_back_edge_scope(bodyScopeResult.raw());
if (UNEXPECTED(backEdgeScope.isUndef())) return;
if (backEdgeScope.isNull() && !bodyIsReplayable) {
backEdgeScope = ptlh::convergedPassBackEdgeScope(nodeScopeResolver, stmt, stmtsHold.raw(), bodyScope.raw(), storage.raw(), context);
if (UNEXPECTED(backEdgeScope.isUndef())) return;
}
if (backEdgeScope.isNull()) {
bodyScope = std::move(prevScope);
brokeOut = true;
Expand Down
12 changes: 12 additions & 0 deletions turbo-ext/src/ForeachHandler.cpp
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Expand Up @@ -543,6 +543,10 @@ class ForeachHandler
if (UNEXPECTED(bodyScopeResult.isUndef())) return;
zv::Val backEdgeScope = pt_internal_statement_result_loop_back_edge_scope(bodyScopeResult.raw());
if (UNEXPECTED(backEdgeScope.isUndef())) return;
if (backEdgeScope.isNull() && !bodyIsReplayable) {
backEdgeScope = ptlh::convergedPassBackEdgeScope(nodeScopeResolver, stmt, parts.stmts.raw(), bodyScope.raw(), storage.raw(), context);
if (UNEXPECTED(backEdgeScope.isUndef())) return;
}
if (backEdgeScope.isNull()) {
bodyScope = std::move(prevScope);
brokeOut = true;
Expand Down Expand Up @@ -1724,6 +1728,14 @@ class ForeachHandler
if (UNEXPECTED(iterBodyScopeResult.isUndef())) return false;
zv::Val backEdgeScope = pt_internal_statement_result_loop_back_edge_scope(iterBodyScopeResult.raw());
if (UNEXPECTED(backEdgeScope.isUndef())) return false;
if (backEdgeScope.isNull()) {
bool bodyIsReplayable;
if (UNEXPECTED(!pt_node_scope_resolver_is_replayable_convergence_body(nodeScopeResolver, stmt, parts.stmts.raw(), bodyIsReplayable))) return false;
if (!bodyIsReplayable) {
backEdgeScope = ptlh::convergedPassBackEdgeScope(nodeScopeResolver, stmt, parts.stmts.raw(), iterBodyScope.raw(), iterStorage.raw(), context);
if (UNEXPECTED(backEdgeScope.isUndef())) return false;
}
}
{
zv::Val breaks = ptlh::breakExitPoints(iterBodyScopeResult.raw());
if (UNEXPECTED(breaks.isUndef())) return false;
Expand Down
21 changes: 21 additions & 0 deletions turbo-ext/src/LoopHandlerCalls.h
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Expand Up @@ -79,6 +79,27 @@ inline zv::Val newPassNodeCallback(bool replayable)
return replayable ? newRecordingNodeCallback() : newNoopNodeCallback();
}

/* a nested loop walks only its first iteration in a pass - its unconverged
* types can make the back edge look dead, so a walk converging it decides:
* $nodeScopeResolver->processStmtNodesInternal($stmt, $stmt->stmts, $entryScope,
* $storage->duplicate(), new NoopNodeCallback(), $context->withoutTemplateArgumentResolution())
* ->filterOutLoopExitPoints()->getLoopBackEdgeScope()
* (UNDEF = pending exception) */
inline zv::Val convergedPassBackEdgeScope(zval *nodeScopeResolver, zval *stmt, zval *stmts, zval *entryScope, zval *storage, zval *context)
{
zv::Val storageCopy = pt_expression_result_storage_duplicate(storage);
if (UNEXPECTED(storageCopy.isUndef())) return zv::Val();
zv::Val noop = newNoopNodeCallback();
if (UNEXPECTED(noop.isUndef())) return zv::Val();
zv::Val walkContext = pt_statement_context_without_template_argument_resolution(context);
if (UNEXPECTED(walkContext.isUndef())) return zv::Val();
zv::Val walked = pt_node_scope_resolver_process_stmt_nodes_internal(nodeScopeResolver, stmt, stmts, entryScope, storageCopy.raw(), noop.raw(), walkContext.raw());
if (UNEXPECTED(walked.isUndef())) return zv::Val();
zv::Val result = pt_internal_statement_result_filter_out_loop_exit_points(walked.raw());
if (UNEXPECTED(result.isUndef())) return zv::Val();
return pt_internal_statement_result_loop_back_edge_scope(result.raw());
}

/* $into = array_merge($into, $more): the array itself when $into is empty and
* $more a list without holes (what array_merge() returns then), appended
* otherwise; false = pending exception */
Expand Down
4 changes: 4 additions & 0 deletions turbo-ext/src/WhileHandler.cpp
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Expand Up @@ -193,6 +193,10 @@ class WhileHandler
bodyScopeResult = pt_internal_statement_result_filter_out_loop_exit_points(walked.raw());
if (UNEXPECTED(bodyScopeResult.isUndef())) return;
backEdgeScope = pt_internal_statement_result_loop_back_edge_scope(bodyScopeResult.raw());
if (UNEXPECTED(backEdgeScope.isUndef())) return;
if (backEdgeScope.isNull() && !bodyIsReplayable) {
backEdgeScope = ptlh::convergedPassBackEdgeScope(nodeScopeResolver, stmt, stmtsHold.raw(), bodyScope.raw(), storage.raw(), context);
}
}();
pt_finally([&]() { (void) pt_mutating_scope_pop_expression_result_storage(Z_OBJ_P(scope.raw())); });
if (UNEXPECTED(EG(exception))) return zv::Val();
Expand Down
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