JIT: Fix register allocator

Fixes oss-fuzz #44916

Author: dstogov

ext/opcache/jit/zend_jit_trace.c

@@ -6389,6 +6389,22 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 	if (p->stop == ZEND_JIT_TRACE_STOP_LOOP
 	 || p->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_CALL
 	 || p->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET) {
+		if (ra) {
+			zend_ssa_phi *phi = ssa->blocks[1].phis;
+
+			while (phi) {
+				if (ra[phi->ssa_var]
+				 && ra[phi->sources[1]]
+				 && STACK_MEM_TYPE(stack, phi->var) != STACK_TYPE(stack, phi->var)
+				 && (ra[phi->ssa_var]->flags & (ZREG_LOAD|ZREG_STORE)) == 0
+				 && (ra[phi->sources[1]]->flags & (ZREG_LOAD|ZREG_STORE)) == 0) {
+					/* Store actual type to memory to avoid deoptimization mistakes */
+					/* TODO: Alternatively, we may try to update alredy generated deoptimization info */
+					zend_jit_store_var_type(&dasm_state, phi->var, STACK_TYPE(stack, phi->var));
+				}
+				phi = phi->next;
+			}
+		}
 		if (p->stop != ZEND_JIT_TRACE_STOP_RECURSIVE_RET) {
 			if ((t->flags & ZEND_JIT_TRACE_USES_INITIAL_IP)
 			 && !zend_jit_set_ip(&dasm_state, p->opline)) {

ext/opcache/jit/zend_jit_x86.dasc

@@ -3867,6 +3867,14 @@ static int zend_jit_store_var(dasm_State **Dst, uint32_t info, int var, zend_reg
 	return zend_jit_spill_store(Dst, src, dst, info, set_type);
 }
 
+static int zend_jit_store_var_type(dasm_State **Dst, int var, uint8_t type)
+{
+	zend_jit_addr dst = ZEND_ADDR_MEM_ZVAL(ZREG_FP, EX_NUM_TO_VAR(var));
+
+	|	SET_ZVAL_TYPE_INFO dst, type
+	return 1;
+}
+
 static int zend_jit_store_var_if_necessary(dasm_State **Dst, int var, zend_jit_addr src, uint32_t info)
 {
 	if (Z_MODE(src) == IS_REG && Z_STORE(src)) {

ext/opcache/tests/jit/reg_alloc_011.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Register Alloction 011: Missed type store
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+--FILE--
+<?php
+function foo($y) {
+    for ($cnt=0;$cnt<6;$cnt++) {
+        $i = $y;
+        for ($i=0;$i<1;)
+            for(;$i<1;)
+                for(;$i<1;$i++)
+                    for(;$y;);
+                for($i=0;$i< 1;$i++)
+                    for(;$y;);
+    }
+}
+foo(null);
+?>
+DONE
+--EXPECTF--
+DONE