perf(optimizer): lower simple integer min/max calls (#96)

* perf(optimizer): lower simple integer min and max calls

* docs(benchmark): focus min/max results on integer performance

benchmark/min-max/README.md

@@ -0,0 +1,35 @@
+# Integer min/max benchmark
+
+This benchmark repeatedly clamps integer values and accumulates a checksum. It
+isolates two-argument integer `min()` / `max()` calls; it is not representative
+of every PHP workload. It emits one line after the loop, so terminal output is
+not part of the hot path.
+
+From this directory, with PHP 8.5 and a matching PHPX/embed installation:
+
+```sh
+php run.php 10000000
+php ../../bin/tpc.php project.yml --no-progress -o min_max_benchmark
+./min_max_benchmark 10000000
+```
+
+The PHP and AOT checksums must match. Compile baseline and candidate revisions
+into different build directories and binary paths, then alternate their
+execution order. Exclude compilation time, discard a warm-up pair, and compare
+medians over multiple runs. Keep PHPX, PHP, compiler flags, and machine fixed.
+
+## Sample result
+
+Linux ARM64 in Docker, PHP 8.5.10 ZTS, PHPX `6a68f38`, GCC `-O2`;
+baseline TypePHP `72b7ce9b` versus this integer min/max lowering change.
+Nine measured runs per binary after one discarded pair, 10,000,000 iterations:
+
+| Build | Median | Range |
+| --- | ---: | ---: |
+| Baseline | 482.56 ms | 456.41–497.78 ms |
+| Integer lowering | 48.01 ms | 44.10–57.38 ms |
+
+This is a 10.05x speedup for the isolated integer min/max workload. Timings
+come from a shared development machine, not a dedicated benchmark host. Raw
+samples are in `results-arm64.json`; times include process startup and exclude
+compilation.

benchmark/min-max/benchmark.php

@@ -0,0 +1,15 @@
+<?php
+
+function main(int $argc, array $argv): void
+{
+    $iterations = $argc > 1 ? (int) $argv[1] : 10000000;
+    $checksum = 0;
+    for ($i = 0; $i < $iterations; ++$i) {
+        $damage = ($i % 101) - 20;
+        $hp = 100 - ($i % 100);
+        $damage = max(0, $damage);
+        $remaining = min($hp, $damage);
+        $checksum += $remaining;
+    }
+    echo $checksum, "\n";
+}

benchmark/min-max/project.yml

@@ -0,0 +1,5 @@
+name: min-max-benchmark
+build-mode: bin
+optimize: 2
+sources:
+  - benchmark.php

benchmark/min-max/results-arm64.json

@@ -0,0 +1,35 @@
+{
+  "baseline": "72b7ce9b",
+  "candidate": "simple integer min/max lowering",
+  "php": "8.5.10 ZTS",
+  "phpx": "6a68f38",
+  "platform": "Linux ARM64 Docker",
+  "optimization": "O2",
+  "method": "alternate order; one discarded pair; nine measured pairs; wall time including process startup; seconds",
+  "count": 10000000,
+  "checksum": "236310950",
+  "samples": {
+    "candidate": [
+      0.057375312,
+      0.045864502,
+      0.048057849,
+      0.045604484,
+      0.048013895,
+      0.045256348,
+      0.04409891,
+      0.048323617,
+      0.049788737
+    ],
+    "baseline": [
+      0.482051066,
+      0.482560355,
+      0.478532421,
+      0.497780501,
+      0.484743119,
+      0.456406973,
+      0.472020001,
+      0.483321787,
+      0.489281674
+    ]
+  }
+}

benchmark/min-max/run.php

@@ -0,0 +1,5 @@
+<?php
+
+require __DIR__ . '/benchmark.php';
+
+main($argc, $argv);

phpunit/code/min-max-integer.php

@@ -0,0 +1,29 @@
+<?php
+function minMaxIntegers(int $a, int $b): array
+{
+    return [min($a, $b), max($a, $b)];
+}
+function minMaxFallbacks(mixed $a, mixed $b): array
+{
+    return [min($a, $b), max($a, $b), min(1.5, 2.5), max(1, 2.5), min([3, 1]), max(1, 2, 3), min(...[3, 1])];
+}
+function minMaxUnproven(mixed $a): array
+{
+    return [min($a + 1, 2), max($a + 1, 2)];
+}
+class MinMaxNullableProperty
+{
+    public ?int $value = null;
+}
+function minMaxNullable(?int $value, MinMaxNullableProperty $object): array
+{
+    return [min($value, 0), max($value, 0), min($object->value, 0), max($object->value, 0)];
+}
+function minMaxCasts(mixed $a): array
+{
+    return [min((int) $a, 2), max((int) $a, 2)];
+}
+function main(): void
+{
+    minMaxIntegers(3, 1);
+}

phpunit/src/MinMaxIntegerTest.php

@@ -0,0 +1,32 @@
+<?php
+
+use TypePhp\CompilerTest;
+
+final class MinMaxIntegerTest extends BaseTest
+{
+    public function testOnlyTwoProvenIntegerArgumentsBypassZend(): void
+    {
+        global $translator;
+
+        $compiler = CompilerTest::create(TYPEPHP_ROOT_PATH);
+        $translator = $compiler;
+        $source = TYPEPHP_ROOT_PATH . '/phpunit/code/min-max-integer.php';
+        $compiler->addFiles([$source]);
+        $compiler->prepareFile($source);
+        $code = file_get_contents($compiler->convertFile($source));
+
+        self::assertIsString($code);
+        $start = strpos($code, 'php::Array php_minmaxintegers(');
+        self::assertNotFalse($start);
+        $end = strpos($code, 'php::Array php_minmaxfallbacks(', $start);
+        self::assertNotFalse($end);
+        $integerBody = substr($code, $start, $end - $start);
+        self::assertStringNotContainsString('php::call(', $integerBody);
+        self::assertSame(13, substr_count($code, 'php::call('));
+        $castStart = strpos($code, 'php::Array php_minmaxcasts(');
+        self::assertNotFalse($castStart);
+        $castEnd = strpos($code, 'void php_main(', $castStart);
+        self::assertNotFalse($castEnd);
+        self::assertSame(2, substr_count(substr($code, $castStart, $castEnd - $castStart), 'php::toInt(a)'));
+    }
+}

src/Optimizer/FuncCallOptimizer.php

@@ -102,6 +102,9 @@ trait FuncCallOptimizer
         ];
 
         $extra = [
+            'min' => ['handler' => 'genIntegerMinMax'],
+            'max' => ['handler' => 'genIntegerMinMax'],
+
             // Aliases (PHP function name → C++ target name)
             'join'             => 'implode',
             'stristr'          => 'stristr',
@@ -1181,6 +1184,61 @@ trait FuncCallOptimizer
         return $array . '.offsetExists(' . $key . ')';
     }
 
+    protected function genIntegerMinMax(string $name, Node\Expr\FuncCall $expr, array $config): string|false
+    {
+        // PHP also accepts arrays, mixed types and variadic arguments. Only
+        // two proven integers have the same comparison and result semantics
+        // as a native scalar selection; leave every other form to Zend.
+        if (count($expr->args) !== 2) {
+            return false;
+        }
+        foreach ($expr->args as $arg) {
+            if (!$this->isExactIntegerMinMaxOperand($arg->value)) {
+                return false;
+            }
+        }
+
+        // Reuse ordinary call operand lowering: materialize side effects once,
+        // but preserve PHP's deferred reads of simple variable arguments.
+        // Casts may warn or invoke an object conversion even without nested
+        // calls, so snapshot them before repeating operands in the selection.
+        $left = $expr->args[0]->value instanceof Node\Expr\Cast\Int_
+            ? $this->parseOrderedOperand($expr->args[0]->value, false, true)
+            : $this->getArg($expr, 0);
+        $right = $expr->args[1]->value instanceof Node\Expr\Cast\Int_
+            ? $this->parseOrderedOperand($expr->args[1]->value, false, true)
+            : $this->getArg($expr, 1);
+        $operator = $name === 'min' ? '<' : '>';
+        return '(' . $left . ' ' . $operator . ' ' . $right . ' ? ' . $left . ' : ' . $right . ')';
+    }
+
+    protected function isExactIntegerMinMaxOperand(Node\Expr $expr): bool
+    {
+        if (!$this->usesNativeScalarStorage(Type::INT)
+            || $this->detectTypeOfExpr($expr) !== Type::INT
+        ) {
+            return false;
+        }
+        if ($expr instanceof Node\Expr\Variable && is_string($expr->name)) {
+            // Require actual native storage, not a flow-sensitive approximation
+            // of the value held by a mixed/overflow-capable variable.
+            return $this->getVarType($this->parseIdentifier($expr)) === Type::INT;
+        }
+        if ($expr instanceof Node\Expr\PropertyFetch && $expr->name instanceof Node\Identifier) {
+            $class = $this->resolveObjectClassDef($expr->var);
+            if ($class !== null && $class->hasProperty($expr->name->toString())) {
+                $property = $class->getProperty($expr->name->toString());
+                return $property->type === Type::INT && !$property->nullable;
+            }
+            return false;
+        }
+        // Arithmetic inference can report INT for mixed + int, even though
+        // the value may be a float. Keep computations, calls and unresolved
+        // property/constant reads on Zend's path.
+        return $expr instanceof Node\Scalar\Int_
+            || $expr instanceof Node\Expr\Cast\Int_;
+    }
+
     protected function genRound(string $n, Node\Expr\FuncCall $e, array $c): string|false
     {
         // An unpacked or named argument is a single Node\Arg whatever its

tests/compiler/functions/min-max-cast-once.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Integer min/max evaluates integer casts exactly once per argument
+--FILE--
+<?php
+class MinMaxWarnings
+{
+    public int $count = 0;
+}
+function main(): void
+{
+    $warnings = new MinMaxWarnings();
+    set_error_handler(static function (int $severity, string $message, string $file, int $line) use ($warnings): bool {
+        ++$warnings->count;
+        return true;
+    });
+    $object = new stdClass();
+    var_dump(min((int) $object, 2), max((int) $object, 0));
+    restore_error_handler();
+    var_dump($warnings->count);
+}
+?>
+--EXPECT--
+int(1)
+int(1)
+int(2)

tests/compiler/functions/min-max-integer.phpt

@@ -0,0 +1,66 @@
+--TEST--
+Integer min/max optimization preserves values, evaluation order, and dynamic fallback
+--FILE--
+<?php
+function nextMinMaxValue(int &$value): int
+{
+    ++$value;
+    return $value;
+}
+function compareMinMax(int $a, int $b): void
+{
+    var_dump(min($a, $b), max($a, $b));
+}
+function dynamicMinMax(mixed $a, mixed $b): void
+{
+    var_dump(min($a, $b), max($a, $b));
+}
+function main(): void
+{
+    compareMinMax(8, -3);
+    compareMinMax(4, 4);
+    compareMinMax(PHP_INT_MIN, PHP_INT_MAX);
+    $value = 2;
+    var_dump(min($value, (int) nextMinMaxValue($value)), $value);
+    var_dump(max(nextMinMaxValue($value), nextMinMaxValue($value)), $value);
+    var_dump(min(nextMinMaxValue($value), $value), $value);
+    $counter = 0;
+    var_dump(false && min(++$counter, ++$counter), $counter);
+    var_dump(true ? max(++$counter, ++$counter) : min(++$counter, ++$counter), $counter);
+    dynamicMinMax('20', 3);
+    dynamicMinMax(false, 2);
+    var_dump(min(1, 1.5), max(1, 1.5), min(-2.5, -1.0), max(-1.0, -2.5));
+    var_dump(min([4, 2]), max(...[1, 7, 3]), min(3, 2, 1));
+    $callable = min(...);
+    var_dump($callable(4, 2));
+}
+?>
+--EXPECT--
+int(-3)
+int(8)
+int(4)
+int(4)
+int(-9223372036854775808)
+int(9223372036854775807)
+int(3)
+int(3)
+int(5)
+int(5)
+int(6)
+int(6)
+bool(false)
+int(0)
+int(2)
+int(2)
+int(3)
+string(2) "20"
+bool(false)
+int(2)
+int(1)
+float(1.5)
+float(-2.5)
+float(-1)
+int(2)
+int(7)
+int(1)
+int(2)

tests/compiler/functions/min-max-nullable.phpt

@@ -0,0 +1,32 @@
+--TEST--
+min/max preserve null arguments and nullable property values
+--FILE--
+<?php
+class MinMaxNullable
+{
+    public ?int $value = null;
+    public static ?int $staticValue = null;
+}
+function nullableMinMax(?int $value): void
+{
+    var_dump(min($value, 0), max($value, 0));
+}
+function main(): void
+{
+    $object = new MinMaxNullable();
+    nullableMinMax(null);
+    var_dump(min($object->value, 0), max($object->value, 0));
+    var_dump(min(MinMaxNullable::$staticValue, 0), max(MinMaxNullable::$staticValue, 0));
+    $object->value = 3;
+    var_dump(min($object->value, 0), max($object->value, 0));
+}
+?>
+--EXPECT--
+NULL
+NULL
+NULL
+NULL
+NULL
+NULL
+int(0)
+int(3)

tests/compiler/functions/min-max-varint.phpt

@@ -0,0 +1,20 @@
+--TEST--
+min/max keep overflow-capable varint values on the Zend path
+--FILE--
+<?php
+use varint_types;
+function main(): void
+{
+    $value = PHP_INT_MAX;
+    ++$value;
+    var_dump(min($value, 2), is_float(max($value, 2)));
+    $value = 1;
+    $value += 0.5;
+    var_dump(min($value, 2), max($value, 2));
+}
+?>
+--EXPECT--
+int(2)
+bool(true)
+float(1.5)
+int(2)

tests/compiler/namespace/min-max-integer-resolution.phpt

@@ -0,0 +1,28 @@
+--TEST--
+Integer min/max optimization respects local functions and imported builtin aliases
+--FILE--
+<?php
+namespace MinMaxGame {
+    use function min as builtinMin;
+    use function max as builtinMax;
+
+    function min(int $a, int $b): int { return 99; }
+    function max(int $a, int $b): int { return -99; }
+    function compare(int $a, int $b): void
+    {
+        var_dump(min($a, $b), max($a, $b));
+        var_dump(builtinMin($a, $b), builtinMax($a, $b));
+        var_dump(\min($a, $b), \max($a, $b));
+    }
+}
+namespace {
+    function main(): void { \MinMaxGame\compare(3, 7); }
+}
+?>
+--EXPECT--
+int(99)
+int(-99)
+int(3)
+int(7)
+int(3)
+int(7)