Fixed NAN handling in SCCP

Fixes oss-fuzz #43341

Author: dstogov

ext/opcache/Optimizer/sccp.c

@@ -183,7 +183,8 @@ static void set_value(scdf_ctx *scdf, sccp_ctx *ctx, int var, zval *new) {
 	}
 
 #if ZEND_DEBUG
-	ZEND_ASSERT(zend_is_identical(value, new));
+	ZEND_ASSERT(zend_is_identical(value, new) ||
+		(Z_TYPE_P(value) == IS_DOUBLE && Z_TYPE_P(new) == IS_DOUBLE && isnan(Z_DVAL_P(value)) && isnan(Z_DVAL_P(new))));
 #endif
 }
 

ext/opcache/tests/opt/sccp_036.phpt

@@ -0,0 +1,16 @@
+--TEST--
+SCCP 036: NAN handling
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+--FILE--
+<?php
+function foo() {
+    $y=NAN;
+    for(;x;)for(;$y=1;);
+}
+?>
+DONE
+--EXPECT--
+DONE