diff --git a/lib/JIT/Builtin/Type/Object_.php b/lib/JIT/Builtin/Type/Object_.php
index 426cb847226..ad15d109d80 100755
--- a/lib/JIT/Builtin/Type/Object_.php
+++ b/lib/JIT/Builtin/Type/Object_.php
@@ -5002,7 +5002,7 @@ private function registerExternalClass(string $lcname, string $displayName): voi
             $pubStatic = $pub | \PHPCfg\Func::FLAG_STATIC;
             foreach ([
                 '__construct', 'count', 'getsize', 'setsize', 'toarray', 'getiterator',
-                'offsetget', 'offsetset', 'offsetexists', 'offsetunset',
+                'offsetget', 'offsetset', 'offsetexists', 'offsetunset', '__debuginfo',
                 'jsonserialize',
             ] as $method) {
                 $this->defineMethodVisibility($id, $method, $pub);
diff --git a/lib/JIT/Call/SplFixedArrayMethod.php b/lib/JIT/Call/SplFixedArrayMethod.php
index b96b522e4a9..10013b2b7e4 100644
--- a/lib/JIT/Call/SplFixedArrayMethod.php
+++ b/lib/JIT/Call/SplFixedArrayMethod.php
@@ -130,6 +130,16 @@ public function call(Context $context, Variable ...$args): Value
                     $index
                 )
             ),
+            '__debuginfo' => $this->callExactArg(
+                $context,
+                $args,
+                'SplFixedArray::__debugInfo',
+                0,
+                static fn (Context $ctx, Variable $self): Value => SplFixedArrayJitHelper::compileDebugInfo(
+                    $ctx,
+                    $self
+                )
+            ),
             default => throw new \LogicException(
                 'SplFixedArray JIT lowering is not implemented for '.$this->method.'()'
             ),
diff --git a/lib/JIT/Context.php b/lib/JIT/Context.php
index c954f4cd186..ff40e1bc9bc 100644
--- a/lib/JIT/Context.php
+++ b/lib/JIT/Context.php
@@ -1884,7 +1884,7 @@ private function defineBuiltins(int $loadType): void {
         $this->type->object->lookup('SplFixedArray');
         foreach ([
             '__construct', 'fromArray', 'count', 'getSize', 'setSize', 'toArray',
-            'offsetGet', 'offsetSet', 'offsetExists', 'offsetUnset',
+            'offsetGet', 'offsetSet', 'offsetExists', 'offsetUnset', '__debugInfo',
         ] as $sfaMethod) {
             $this->functionProxies['splfixedarray::'.strtolower($sfaMethod)] = new Call\SplFixedArrayMethod($sfaMethod);
         }
diff --git a/lib/JIT/VarDumpObjectDebugPropertiesLlvm.php b/lib/JIT/VarDumpObjectDebugPropertiesLlvm.php
new file mode 100644
index 00000000000..0b527ff9d1c
--- /dev/null
+++ b/lib/JIT/VarDumpObjectDebugPropertiesLlvm.php
@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler\JIT;
+
+use PHPCompiler\ext\standard\JitGetObjectVars;
+use PHPCompiler\JIT\Variable as JitVariable;
+use PHPCompiler\VM\SplFixedArrayJitHelper;
+use PHPLLVM\Builder;
+use PHPLLVM\Value;
+
+/**
+ * var_dump() object property source — __debugInfo / spl backing ht before get_object_vars (#19783).
+ *
+ * php-src: ext/standard/var.c — zend_std_get_debug_info / spl_fixedarray_object_debug_info
+ */
+final class VarDumpObjectDebugPropertiesLlvm
+{
+    private static int $seq = 0;
+
+    /**
+     * Hashtable of properties to dump for $objVar (may branch on runtime class).
+     */
+    public static function resolveHashtable(Context $context, JitVariable $objVar): Value
+    {
+        $objPtr = self::objectPtr($context, $objVar);
+        $object = $context->type->object;
+        $sfaClassId = $object->lookup('SplFixedArray');
+        $objMap = $context->structFieldMap['__object__'];
+        $runtimeClassId = $context->builder->load(
+            $context->builder->structGep($objPtr, $objMap['class_id'])
+        );
+        $isSplFixedArray = $context->builder->icmp(
+            Builder::INT_EQ,
+            $runtimeClassId,
+            $context->constantFromInteger($sfaClassId)
+        );
+
+        $tag = (string) ++self::$seq;
+        $sfaBb = BasicBlockHelper::append($context, 'vd_dbg_sfa_'.$tag);
+        $govBb = BasicBlockHelper::append($context, 'vd_dbg_gov_'.$tag);
+        $doneBb = BasicBlockHelper::append($context, 'vd_dbg_done_'.$tag);
+        $htTy = $context->getTypeFromString('__hashtable__*');
+        $htSlot = BasicBlockHelper::entryAlloca($context, $htTy);
+        $context->builder->branchIf($isSplFixedArray, $sfaBb, $govBb);
+
+        $context->builder->positionAtEnd($sfaBb);
+        $receiver = new JitVariable(
+            $context,
+            JitVariable::TYPE_OBJECT,
+            JitVariable::KIND_VALUE,
+            $objPtr
+        );
+        $sfaHt = SplFixedArrayJitHelper::copyPackedHashtable($context, $receiver);
+        $context->builder->store($context->helper->loadValue($sfaHt), $htSlot);
+        $context->builder->branch($doneBb);
+
+        $context->builder->positionAtEnd($govBb);
+        $context->builder->store(self::hashtableFromGetObjectVars($context, $objVar), $htSlot);
+        $context->builder->branch($doneBb);
+
+        $context->builder->positionAtEnd($doneBb);
+
+        return $context->builder->load($htSlot);
+    }
+
+    private static function hashtableFromGetObjectVars(Context $context, JitVariable $objVar): Value
+    {
+        $varsBoxed = JitGetObjectVars::invoke($context, $objVar, false);
+
+        return $context->builder->call(
+            $context->lookupFunction('__value__readHashtable'),
+            JitValueBox::normalizeValuePtr($context, $varsBoxed)
+        );
+    }
+
+    private static function objectPtr(Context $context, JitVariable $objVar): Value
+    {
+        if (JitVariable::TYPE_OBJECT === $objVar->type) {
+            return JitVariable::KIND_VALUE === $objVar->kind
+                ? $objVar->value
+                : $context->builder->load($objVar->value);
+        }
+
+        return $context->builder->call(
+            $context->lookupFunction('__value__readObject'),
+            JitValueBox::valuePtrFromVariable($context, $objVar)
+        );
+    }
+}
diff --git a/lib/JIT/VarDumpObjectLlvm.php b/lib/JIT/VarDumpObjectLlvm.php
index 2f958a3490a..ef2aebd218a 100644
--- a/lib/JIT/VarDumpObjectLlvm.php
+++ b/lib/JIT/VarDumpObjectLlvm.php
@@ -4,7 +4,6 @@
 
 namespace PHPCompiler\JIT;
 
-use PHPCompiler\ext\standard\JitGetObjectVars;
 use PHPCompiler\JIT\Call\HashTableExportKeyValuePairs;
 use PHPCompiler\JIT\Variable as JitVariable;
 use PHPLLVM\Builder;
@@ -41,11 +40,7 @@ public static function dump(Context $context, Value $valuePtr, Value $level): vo
             $valuePtr
         );
         $className = ReflectionBuiltinHelper::getDebugTypeClassName($context, $objVar);
-        $varsBoxed = JitGetObjectVars::invoke($context, $objVar, false);
-        $ht = $context->builder->call(
-            $context->lookupFunction('__value__readHashtable'),
-            JitValueBox::normalizeValuePtr($context, $varsBoxed)
-        );
+        $ht = VarDumpObjectDebugPropertiesLlvm::resolveHashtable($context, $objVar);
 
         $pairs = HashTableExportKeyValuePairs::exportPairsForSlice($context, $ht);
         $num = $context->builder->call(
diff --git a/lib/VM/SplFixedArrayJitHelper.php b/lib/VM/SplFixedArrayJitHelper.php
index a53e6d4e672..c69dd5945ec 100644
--- a/lib/VM/SplFixedArrayJitHelper.php
+++ b/lib/VM/SplFixedArrayJitHelper.php
@@ -4,12 +4,14 @@
 
 namespace PHPCompiler\VM;
 
+use PHPCompiler\CompilerVersion;
 use PHPCompiler\ext\standard\JitIntdiv;
 use PHPCompiler\JIT\BasicBlockHelper;
 use PHPCompiler\JIT\Context;
 use PHPCompiler\JIT\ExceptionBridge;
 use PHPCompiler\JIT\HashTableHelper;
 use PHPCompiler\JIT\JitValueBox;
+use PHPCompiler\JIT\TryCatchHelper;
 use PHPCompiler\JIT\Variable as JITVariable;
 use PHPLLVM\Builder;
 use PHPLLVM\Value;
@@ -206,6 +208,29 @@ public static function compileSetSize(Context $context, JITVariable $receiver, J
      * Peer {@see ArrayObjectJitHelper::compileGetArrayCopy}.
      */
     public static function compileToArray(Context $context, JITVariable $receiver): Value
+    {
+        $slot = JitValueBox::alloc($context);
+        $context->builder->call(
+            $context->lookupFunction('__value__writeHashtable'),
+            JitValueBox::pointer($context, $slot),
+            $context->helper->loadValue(self::copyPackedHashtable($context, $receiver))
+        );
+
+        return $slot;
+    }
+
+    /**
+     * SplFixedArray::__debugInfo() — indexed element map (php-src spl_fixedarray_object_debug_info; #19783).
+     */
+    public static function compileDebugInfo(Context $context, JITVariable $receiver): Value
+    {
+        return self::compileToArray($context, $receiver);
+    }
+
+    /**
+     * Copy fixed `__spl_ht` slots for var_dump / __debugInfo (peer compileToArray).
+     */
+    public static function copyPackedHashtable(Context $context, JITVariable $receiver): JITVariable
     {
         $ht = self::htPtr($context, self::loadObject($context, $receiver));
         $copy = new JITVariable(
@@ -219,14 +244,8 @@ public static function compileToArray(Context $context, JITVariable $receiver):
             $copy,
             new JITVariable($context, JITVariable::TYPE_HASHTABLE, JITVariable::KIND_VALUE, $ht)
         );
-        $slot = JitValueBox::alloc($context);
-        $context->builder->call(
-            $context->lookupFunction('__value__writeHashtable'),
-            JitValueBox::pointer($context, $slot),
-            $context->helper->loadValue($copy)
-        );
 
-        return $slot;
+        return $copy;
     }
 
     public static function compileOffsetGet(Context $context, JITVariable $receiver, JITVariable $index): Value
@@ -400,13 +419,14 @@ private static function assertIndexInRange(Context $context, Value $ht, Value $i
         $okBb = BasicBlockHelper::append($context, 'sfa_oob_ok');
         $context->builder->branchIf($ok, $okBb, $badBb);
         $context->builder->positionAtEnd($badBb);
-        $msg = 'Index invalid or out of range';
-        $context->builder->call(
-            $context->lookupFunction('__compiler_jit_raise_logic_exception'),
-            $context->builder->pointerCast($context->constantFromString($msg), $context->getTypeFromString('int8*')),
-            $context->constantFromInteger(\strlen($msg), 'size_t')
+        $exceptionClass = CompilerVersion::supportsSplFixedArrayOutOfBoundsException()
+            ? 'OutOfBoundsException'
+            : 'RuntimeException';
+        TryCatchHelper::emitCatchableClassError(
+            $context,
+            $exceptionClass,
+            'Index invalid or out of range'
         );
-        $context->builder->branch($okBb);
         $context->builder->positionAtEnd($okBb);
     }
 
diff --git a/test/unit/SplFixedArrayDebugInfo19783AotTest.php b/test/unit/SplFixedArrayDebugInfo19783AotTest.php
new file mode 100644
index 00000000000..68fe0b8438f
--- /dev/null
+++ b/test/unit/SplFixedArrayDebugInfo19783AotTest.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * AOT: SplFixedArray __debugInfo var_dump + OOB catchable exceptions (#19783, #21994).
+ *
+ * @see php-src ext/spl/spl_fixedarray.c spl_fixedarray_object_debug_info
+ *
+ * @group llvm
+ * @group aot
+ */
+final class SplFixedArrayDebugInfo19783AotTest extends TestCase
+{
+    private const DEBUG_EXPECTED = <<<'OUT'
+object(SplFixedArray)#1 (2) {
+  [0]=>
+  int(1)
+  [1]=>
+  NULL
+}
+
+OUT;
+
+    private const OOB_EXPECTED = "caught:RuntimeException\nafter\n";
+
+    public function testContextRegistersDebugInfoProxy(): void
+    {
+        $ctx = (string) file_get_contents(__DIR__.'/../../lib/JIT/Context.php');
+        $this->assertStringContainsString("'__debugInfo'", $ctx);
+        $this->assertStringContainsString(
+            "'offsetGet', 'offsetSet', 'offsetExists', 'offsetUnset', '__debugInfo'",
+            $ctx
+        );
+    }
+
+    public function testVmSplFixedArrayDebugInfoRepro(): void
+    {
+        $runtime = new Runtime();
+        $code = file_get_contents(dirname(__DIR__).'/repro/splfixedarray_debug_info.php');
+        $this->assertNotFalse($code);
+        $cwd = getcwd();
+        chdir(dirname(__DIR__, 2));
+        try {
+            ob_start();
+            $runtime->run($runtime->parseAndCompile($code, 'splfixedarray_debug_info.php'));
+            $out = (string) ob_get_clean();
+        } finally {
+            chdir($cwd);
+        }
+        $this->assertMatchesRegularExpression(
+            '/object\(SplFixedArray\)#\d+ \(2\) \{\n  \[0\]=>\n  int\(1\)\n  \[1\]=>\n  NULL\n\}\n/',
+            $out
+        );
+    }
+
+    public function testAotSplFixedArrayDebugInfoRepro(): void
+    {
+        if (!LlvmToolchain::hasLibrary(dirname(__DIR__, 2))) {
+            $this->markTestSkipped('LLVM 9 toolchain not available');
+        }
+        $this->assertSame(self::DEBUG_EXPECTED, $this->runAot(dirname(__DIR__).'/repro/splfixedarray_debug_info.php'));
+    }
+
+    public function testAotSplFixedArrayOobCatchableRepro(): void
+    {
+        if (!LlvmToolchain::hasLibrary(dirname(__DIR__, 2))) {
+            $this->markTestSkipped('LLVM 9 toolchain not available');
+        }
+        $this->assertSame(
+            self::OOB_EXPECTED,
+            $this->runAot(dirname(__DIR__).'/repro/splfixedarray_oob_catchable_21994.php')
+        );
+    }
+
+    private function runAot(string $src): string
+    {
+        $root = dirname(__DIR__, 2);
+        $bin = sys_get_temp_dir().'/phpc_sfa19783_'.getmypid().'.bin';
+        $compile = 'env PHP_COMPILER_HELPER_RUNTIME_O=0 '.escapeshellarg(PHP_BINARY).' '
+            .escapeshellarg($root.'/bin/compile.php')
+            .' -o '.escapeshellarg($bin).' '.escapeshellarg($src).' 2>&1';
+        exec($compile, $compileOut, $compileRc);
+        $this->assertSame(0, $compileRc, implode("\n", $compileOut));
+        $this->assertFileExists($bin);
+        try {
+            $runOut = [];
+            exec(escapeshellarg($bin).' 2>&1', $runOut, $runRc);
+            $this->assertSame(0, $runRc, implode("\n", $runOut));
+
+            return implode("\n", $runOut)."\n";
+        } finally {
+            @unlink($bin);
+        }
+    }
+}