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AOT: native double widen for float locals — mandelbrot 248k→121k IR (#36407) #36428

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Merged
PurHur merged 1 commit into from
Sep 2, 2026
Merged

AOT: native double widen for float locals — mandelbrot 248k→121k IR (#36407) #36428

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72 changes: 70 additions & 2 deletions lib/JIT.php
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Original file line number Diff line number Diff line change
Expand Up @@ -20645,6 +20645,70 @@ private function promoteNativeLongLvalueToValueBox(
$this->markScopeVariableAssignedIfTracked($resultOp, $promoted);
}

/**
* Widen `$x = 0; $x = 0.7` locals to a native double alloca instead of a heap
* __value__ box so float loops stay on fadd/fmul (#36407 / #23471).
*/
private function promoteNativeLongLvalueToNativeDouble(
Operand $resultOp,
Variable $result,
Variable $value
): void {
$oldAlloca = null;
if (Variable::KIND_VARIABLE === $result->kind
&& Variable::TYPE_NATIVE_LONG === $result->type
&& null !== $result->value
) {
$oldAlloca = $result->value;
}
if (!$result->includeBinding) {
$result->free();
}
$doubleTy = $this->context->getTypeFromString('double');
$slot = JIT\BasicBlockHelper::entryAlloca($this->context, $doubleTy);
if (Variable::TYPE_NATIVE_DOUBLE === $value->type) {
$fp = $this->context->helper->loadValue($value);
} elseif (Variable::TYPE_VALUE === $value->type && null !== $value->compileTimeFloat) {
$fp = $doubleTy->constReal($value->compileTimeFloat);
} else {
throw new \LogicException('promoteNativeLongLvalueToNativeDouble: unexpected value type '.$value->type);
}
$this->context->builder->store($fp, $slot);
if (null !== $oldAlloca) {
$longVal = $this->context->builder->fpToSi(
$fp,
$this->context->getTypeFromString('int64')
);
$this->context->builder->store($longVal, $oldAlloca);
}
$promoted = new Variable(
$this->context,
Variable::TYPE_NATIVE_DOUBLE,
Variable::KIND_VARIABLE,
$slot
);
$promoted->compileTimeConstantName = $value->compileTimeConstantName;
$promoted->compileTimeEnumCase = $value->compileTimeEnumCase;
$promoted->compileTimeFloat = $value->compileTimeFloat;
$promoted->compileTimeLong = null;
$this->syncCompileTimeString($promoted, $value, false);
$this->context->setVariableOp($resultOp, $promoted);
$resolved = JIT\OperandName::resolve($resultOp);
if (null !== $resolved && '' !== $resolved) {
$this->context->bindVariableByName(
$this->context->resolveRefAliasName($resolved),
$promoted
);
}
$this->markScopeVariableAssignedIfTracked($resultOp, $promoted);
}

private function nativeLongWidenAssignIsNativeDouble(Variable $value): bool
{
return Variable::TYPE_NATIVE_DOUBLE === $value->type
|| (Variable::TYPE_VALUE === $value->type && null !== $value->compileTimeFloat);
}

/**
* First assignment to a script global must populate the heap box (#1492 bootstrap-aot).
*
Expand Down Expand Up @@ -23211,11 +23275,15 @@ function () use ($result, $value): void {
} elseif ($result->type === Variable::TYPE_NATIVE_LONG && Variable::TYPE_VALUE === $value->type) {
// Untyped locals must widen on float (and other) assigns — truncating via
// fpToSi made `$s = 0; $s = 0.028` store 0 and broke mandelbrot AOT (#23471).
$this->promoteNativeLongLvalueToValueBox($resultOp, $result, $value);
if ($this->nativeLongWidenAssignIsNativeDouble($value)) {
$this->promoteNativeLongLvalueToNativeDouble($resultOp, $result, $value);
} else {
$this->promoteNativeLongLvalueToValueBox($resultOp, $result, $value);
}

return;
} elseif ($result->type === Variable::TYPE_NATIVE_LONG && Variable::TYPE_NATIVE_DOUBLE === $value->type) {
$this->promoteNativeLongLvalueToValueBox($resultOp, $result, $value);
$this->promoteNativeLongLvalueToNativeDouble($resultOp, $result, $value);

return;
} elseif ($result->type === Variable::TYPE_NATIVE_LONG && Variable::TYPE_NATIVE_BOOL === $value->type) {
Expand Down
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